THE EFFECTS OF STRUCTURE ON THE PHYSICAL PROPERTIES OF SOME HIGH MOLECULAR WEIGHT HYDROCARBONS. I. CENTER-CYCLIZED CHAINS. II. METHYL-BRANCHED ISOPARAFFINS. III. THE PERHYDROBENZ(DE)ANTHRACENE GROUP

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DOCTORAL DISSERTATION SERIES

sreoc.tube AHYS/CAL />£OE£ET/ES Of 30M£ H/GH MtCECULM WE/GMT HYAEOCA^BONS I CE/YTEECYCL UED C H AM JT- METHYL- BEAMCHEA /S6At£/)ff//USHE. THE PEEHyAEdBEAZ.6**)___ AA/THAACEHE GEOVA a u th o r rJOffM AEEO£E/CAi M6ELEE____________ u n i v e r s i t y

DEGREE

EEAI/I/. STATE COLL.

PA-0■_______

d a t e

PUBLICATION NO. I|l|l|l[l|l|^|l|»|ip[l|l|^jl|l|l|»[l|l|ljl

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UNIVERSITY MICROFILMS A N N

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The Pennsylvania State College The Graduate School Department of Chemistry

The Effects of Structure on the Physical Properties of Some High Molecular 'Weight Hydrocarbons I.

Center-cyclized Chains

II. Methyl-branched Isoparaffins III. The Perhydrobenz(de)anthracene Group

A Thesis toy J o h n Frederick Hosier Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy June, 1951 Approved: A s s t . Professop^o’f Chemistry H e a d , D/p $ t . of Chemistry

ACKNOWLEDGEMENT

The author expresses his sinoere appreciation to Professor Robert W. Schiessler for his untiring in­ spiration and encouragement and his direction throughout the course of this work.

Many thanks to Dr. J. A. Dixon

and the Research Staff of Project 42 for their assistance, cooperation, and suggestions. The writer is indebted to the American Petroleum Institute and to the American Cyanamid Company for the grants which supported this work.

TABLE OF CONTENTS Page Introduction

......................................

1

...........................................

3

The Hydrocarbons P r e p a r e d .........................

7

Physical Properties of the Hydrocarbons .........

10

History

Influence of Structure on Physical Properties...

19

Center-cyclized C h a i n s .........................

31

Methyl-branched Isoparaffins...... ..........

36

The Perhydrobenz(de)anthracene Croup.........

49

Ring Analysis M e t h o d s .............................. 54 Syntheses General Synthetic M e t h o d s ......................

58

Preparation of the Hydrocarbons 1,4-Di-n-decylbenzene........................

60

Discuss ion ..................................

60

Ex perimental ................................

65

Intermediates Terephthalic a c i d ......................

65

Terephthalyl chloride.................

65

N-Tetraethylterephthalamide..........

66

Nonyl b r o m i d e ..........................

67

p-Didecanoyl b e n z e n e ..................

68

1,4-Di-n-deoylbenzene

74

Page Attempted Syntheses of 1,4-Di-n-alkylbenzenes Di scu ssi on .................................

83

Experimental...............................

87

p-Phenylenedimagnesium b r o m i d e ........

87

Terephthalaldehyde with Octylmagnesium b r o m i d e ...................

88

Intermediates p - X y l e n e ................

88

a,a,a*,a'-Tetrabromo-p-xylene

88

Terephthalaldehyde.................

91

Octyl b r o m i d e .......................

92

The R e a c t i o n ..........................

92

Terephthalyl chloride with Di-n-nonyl ca dmi um ..................................

95

Intermediates Terephthalic a c i d .................

95

Terephthalyl chloride.............

95

Nonyl b r o m i d e ......................

96

The R e a c t i o n .........................

98

Terephthalyl chloride with Nonylmagnesium b r o m i d e .........................

101

Dimethyl terephthalate with Nonylmagnesium b r o m i d e .........................

103

Intermediates Dimethyl terephthalate...........

103

The R e a c t i o n .........................

104

Page

p-Phenylenediacetonitrile with Octylmagnesium b r o m i d e .......................

105

Intermediates p - X y l e n e.............

105

a,a'-Dibromo-p-xylene............

105

p-Phenylenediacetonitrile........

106

The R e a c t i o n .........................

108

p-Phenylenediacetyl chloride with Octylmagnesium b r o m i d e ...................... 109 Intermediates p-Phenylenediacetic a c i d .........

109

p-Phenylenediacetyl chloride

Ill

The R e a c t i o n .........................

114

,2,4,10,12.12-Hexamethyl-7(3,5,5-triethylhexyl56-t r i d e cen e...................

116

Discuss ion ................................

116

Experimental ..............................

117

B

CO

1,4-Di-n-decylcyolohexane

Ill

Intermediates Ethyl c arb onate......................

117

3.5.5-Trimethylhexanol- l ...........

117

3.5.5-Trimethyl-1-bromohexan e ......

118

3,5,5-Trimethylhexanoic a c i d

119

Ethyl-3,5,5-trimethylhexanoate...

119

2,2,4,10,12^.2-Hexamet hyl-7 (3,5,5trimethylhexyl)7-tridecanol........

122

Page 2,2,4,10,12.12-Hexamethyl-7(3,5,5-trimethylhexylJ6-t rid e c e n e.................

126

2,2,4 «10,12,12-Hexamethyl-7(3,5,5-trimethylh e x y l 5tri de c a n e ...............................

128

2,2,4,15,17.17-Hexamethyl-7,12-di(3,5,5-trimethylhexyljoctadecane.......................

132

D isc uss ion.........................

132

Experimental................................

132

Intermediates Diethyladipate.........................

133

2,2,4,15,17,17-Hexamethyl-7,12-di(3,5,5trimethylhexyl)7,12-octadecandiol

133

o l e f i n s ............................

134

2,2,4,15,17,17-Hexamethy1-7,12-di(3,5,5trimethylhexyl)octadecane. ............

134

6-n-0ctylperhydrohenz(de)anthrace ne ......

139

Discussion ...............................

139

Ex per ime nta l..............................

142

Intermediates Benzanthrone .........................

142

6-n-0ctylbenz(d e )anthracen-7-one...

142

Reaction of Benzanthrone with nHe x y l l i t h i u m .........................

148

6-n-0ctylperhydrobenz(de)anthracene.. Synthetic and Purification A p p a r a t u s ......... Summary.

...........................................

Bibliography...................

149 158 165 168'

INTRODUCTION

The research reported herein is a portion of the work being carried out at the Pennsylvania State College by a group of graduate students under the direction of Professor Robert «V. Schiessler.

The efforts of the group are directed

mainly toward the following objectives: 1.

To prepare a large number of pure heavy hydrocar­

bons in the CgQ to O5Q molecular weight range.

Hydrocarbons

to be synthesized are selected so that a great variety of molecular types is included, and so that well defined but small gradations in structure will yield maximum informa­ tion in making physical property comparisons. 2.

To determine precisely a large number of physical

properties on the hydrocarbons prepared, and correlate the physical properties with chemical structure. lations,

Such corre­

it is hoped, will lead to knowledge of the funda­

mental nature and significance of viscosity and to funda­ mental relationships of other properties.

The data will

also be of use in physical-chemical calculations. 3.

To test with compounds of known structure the

various methods of determining additive properties such as molecular refraction, molecular volume,

etc., and also

methods for determining average hydrocarbon type in an oil. 4.

To develop reliable methods of preparation and

purification of high molecular weight hydrocarbons.

5.

To determine the relationships which exist between

the physical properties of hydrocarbon mixtures and their components. In this thesis the details of synthesis and purifi­ cation, the physical properties and their determinations, the influenoe of the structure on the physical properties, and methods of calculating properties and analyzing oils for hydrocarbon type are discussed for six heavy hydrocarbons. The compounds whose names and structures are listed in the third section are of three general structural types: (a)

Dialkyl substituted six membered rings.

(b)

Highly methyl-branched aliphatics.

(c)

Fused ring naphthenes. The synthesis of a p-dialkyl benzene free of posi­

tional isomers was found to be a difficult task.

The failures

of several methods, using bifunctional intermediates whose monofunctional counterparts are known to give good yields of mono substituted benzenes with Grignard reagents, are reported. Cyclization of the center, as opposed to the end, of a long chain hydrocarbon has been shown to result in surprisingly small physical property changes. The three branched aliphatics allow the first phy­ sical prdperty study of such structures at the high molecular weight level. Investigation of the properties of the fused ring naphthene

compound indicates that previous generalizations

regarding properties versus per cent carbon atoms in rings must be modified to incorporate ring positions. The physical properties determined for each com­ pound are tabulated in the fourth section of the thesis.

HISTORY

The detailed investigations of Mabery^S, later workers,

and

concerning the chemical structures of lub­

ricating oil, have led to the study of the properties of synthetic high molecular weight hydrocarbons to obtain more exact knowledge for use in the petroleum field and in the study of fundamental physical-chemical relationships.

The

initial work from this viewpoint was performed by Hugel^® who prepared several aliphatic, aromatic, and hydroaromatic hydrocarbons

in the high molecular weight range and tried

to correlate their physical properties with their chemical structures. Suida and F l a n c k h ^

studied the properties of

isoparaffins prepared by themselves and of those available in the literature at the time.

Similar but more extensive

work was carried out by Schmidt on alkylbenzenes

51

, alkyl-

cyclohexanes5*5, alkylcyclopentanes5 5 , p-alkyltoluenes^4 , normal paraffins and 1-olefins5 5 . Recently, Neyman-Pilat and Pilat5® have published correlations of the physical properties of seven new 23carbon aromatic and hydroaromatic hydrocarbons. Contributions have also been made by Deanesly and Carleton^7 and Francis5® toward correcting the avail­ able data on n-paraffin and isoparaffin hydrocarbons and correlating their physical properties. In a study of the properties of fifty-two synthe­ sized aromatic and hydroaromatic hydrocarbons, Mikeska^®

formulated many generalizations concerning the relation of physical properties to chemical structure.

The work

did much to lay a sound foundation for the field. From a study of the oxidation characteristics of forty pure hydrocarbons of representative types, Larsen and co-workers60 obtained useful information relative to the effects of structural factors upon oxidation stability. In general it was found that pure hydrocarbons are extremely susceptible to oxidation, and that natural oils are stabil­ ized by impurities which are natural inhibitors.

While the

study of this chemical property is of paramount importance to the petroleum and chemical industry,

it affords valuable

information concerning the handling and storing of pure hydrocarbon samples such as those prepared in this work. Boiling points, melting points,

densities, viscosities,

viscosity indices, aniline points, refractive indices, and specific dispersions were determined for the compounds, but no attempt was made to correlate the physical properties with chemical structure. The major contribution to this field has come through the efforts of American Petroleum Institute, Project 42.

To date, over 200 pure hydrocarbons of the following

types have been synthesized: n-paraffins and olefins, branched paraffins and olefins, non-fused aromatics, fused ring aromatios, non-fused naphthenes, thenes.

and fused ring naph-

For each compound 17 physical properties have

been determined experimentally or calculated at several temperatures. Most of the investigations of earlier workers were carried out with compounds of questionable structure and purity, and much of the work of the group has been directed toward the development of reliable methods for preparation and purification of hydrocarbons in the CgQ to C50 range6-*--6 8 . Many tentative generalizations regarding the effect of chemical structure on physical properties have been proposed and some have been published

•

Work

toward the integration of such generalizations into a workable structure-property theory, to viscosity,

is b eing carried out.

especially as pertains

THE HYDROCARBONS PREPARED

Approximately 200 g. each of the six hydrocarbons studied were synthesized.

All have been shown to be better

than 95 mole per cent pure by calorimetric or mass spectral data.

A PSC number is assigned to each completed hydrocarbon

for purposes of easy identification. The effect on physical properties of moving a phenyl or cyclohexyl group along a 20-carbon straight chain 70 71 has been thoroughly studied * (e.g., l-phenyleicosane, 2-phenyleicosane, 3-phenyleicosane,etc.).

PSC 152 and 153

are the first of a Beries to be prepared in order to study the effects of changing the position of the benzene or cyclo— hexane ring in the 20-oarbon chain,

i.e., cyclizing various

portions of a 26-carbon straight chain,

in this case the

center six carbon atoms. PSC~l52 1,4-Di-n-Decylbenz ene ^10

PS0~153 1,4-Di-n-Decylcyclohexane ^io

The effect on physical properties of multiple branching in the isoparaffins has been investigated for such compounds as 5,14-di-n-butyloctadecane, 6 ,11-di-namylhexadecane, and 3-ethyl-5(2-ethylbutyl)octadecane.69 >70

8. PSC 182, 183, and 184 were prepared to observe the effects on physical properties of a high degree of methyl-branching in the larger molecules.

P80 182 2,2,4,15,17,17-Hexamethyl-7,12 -di (3,5,5-trimethylhexyl)octadecane

C

G

C

C-C-C-C-C-C

C-C-C-C-C-C

0

\

/

5

/

\

^

G

t

C-C-C-G-C-C.

C-G-C-G-C-C

t

t

G

C

C

x

G-G-G-C-C-G

i t

C

G

PSG 183 2 ,2,4,10,12,12-Hexamethyl-7(3,5,5-trimethylhexyl)6-txldecene

c

c

C-C-C-C-C-C

t G

-

v \

o »

«

C=C-C-C-C-C-C

0

» t

/

C-C-G-C-G-C

c

-

o i

/

c1

«

c

*!§■

PSG 184 2 , 2 ,4 ,10,12 ,l2-Hexametbyl-7(3,5,5-t rimethy lhexyl) trideoane

c

c

C-C-C-C-C-C i \ o G C \ t t ^ C-G-C-C-G-C-G v

1 t G

/

C-J-C-C-C-C

t G

/

»

r

0

9.

Fused ring naphthenes containing saturated naphtha­ lene, acenaphthene,

anthracene,

fluorene, and naphthacene

nuclei have been prepared and studied at Penn State.

Cycli-

zation of the carbon chains to fused rings produces inter­ esting effects on the physical properties.

The hydrocarbons

containing four condensed rings have amazingly high vis­ cosities.^^

The preparation of the perhydrobenzanthracene

compound, PSC 196,

seemed desirable in order to compare the

physical properties with those of the hydrocarbons mentioned above and because of the interesting chemistry involving the a, £-unsaturated ketone, benzanthrone.

PSC 196 6- n -0 ctylperhydrobenz(d e )anthracene

PHYSICAL PROPERTIES OF THE HYDROCARBONS

The lack of recorded physical properties for organic compounds is undoubtedly not so much the result of disinterestedness as it is of the difficult problem of designing,

constructing, and calibrating the intricate equip­

ment and formulating and standardizing the techniques re­ quired to produce such data.

A great effort has been made

since the inception of API 42 to increase the number of useful physical constants determined,

to devise the necessary

apparatus, and to find or develop reliable standard methods. The physical properties of the six hydrocarbons prepared are presented in Table I. Several properties of three intermediates, 3,3,4,10,12,12-hexamethyl-7(3,5,5-trimethylhexyl)7-tridecanol, ethyl-3,5,5-trimethylhexanoate,

and 3,5,5-trimethylhexanoic

acid, are also included in Table I. The apparatus and the methods uBed to determine the properties are described below.

Where possible, refer­

ences are made to detailed descriptions in available pub­ lications . Calibration constants of the apparatus and data pertinent to the determinations are tabulated for easy reference. Viscosity:

Cannon-Fenske type viscometers as described in

AS TM D445-39T method B were used for kinematic viscosity measurements at 33.0, 68.0, 100.0, 140.0, and 21 0.0°F. 20.0, 37.8, 60.0, and 98.S°C.)

(0.0,

The values are reproducible

Sil-w(■ < ■

' r'"^Wf^rci',w^*,’ i' T"i r i ‘iwjir"r

•?*•" 1.v1 ”*’*'

Table I

Structure;; and Properties of the Compounds Prepared Hydrocarbon

PSC Ho.

1^2

l^Di-n^Decylbenjiene1

153

1,9-Di-n-Decylohexane

C10 -O^:o 610 ’Q^IO C

?

l8j

;• 2,2,t)-,10,12,12-HGxa)nethyl-7-(jj5>5^-C-C-C-Ctrimethylhexyl)-6-trldecene

199

2,2,V }10,12,12-llexylme thyl- 7(3,5,5tr ime thylhexyl)tr idecane

c-cw-c

•C-C-C-C-lf-C

Absolute fiscosity in Centlnolses at0 F_ _ _ _ _ _ _ _

32°'

32°

63°

100° IkD0 210°

63d . 100°

lV0°

C-C-C-C-C-C-C

210°

100° 00,5

358,8

53A

22,0A 12.13 8.D77 3,398

V 5.9a

13.3A 10,25 5.633 2.635

^2^52

j6V,7.

89*

31.5A 16.60 3.929 v .039

71A

26. 2a l j . 69 7.211 3.201

CusHgs

591.1

3030 952.1 123,9 90.9] 10.73

25.22

370.9 109.1+ 32.50 3.233

595.5

C 23% j

392.7

192 91.22 13.25 8,69? 3.558

121.6

33.39 19.55 6,775 2.700

°0,2

C 2SH53

S 25*^3

Cfl

399,7

j9j.6

CjgHjfjO tflG,7

267.2 62.07 2l4.65+ P0.6J 1+.009

213,2

99.92 19.59 q.295 3*02j

117.9

2797 3^7.7 9^.69 29.73 7.938

2629

329.0 39,28 27.31 7.109

937.5

170,joo 3513 9^6.3 65.73 9.310

160,900

2953 361.1 5j .92 7 . j 25

E thyl-j,9(5- tr ime thy Dicxona te

C u H 220

138.9

3.199 2,059 1.522 1,1ft .7262

2.760

1.779 1.289 .9236 .5771

3,5,9-Trtethylhexanolc acid

CoHl8D 2

158.2

29,95 12.?0 7.256 9,206 2.069

26.91

11.9? 6.92? 3.655 1.737

-

Extrapolated value Supercooled Sample Viscosity too low Could not be crystallized

f

I

vo

Xrv

cvj

i * = ? ] I •! 1

o O

co

I

g> 5Z3 -i— 1

cj>

-

O v

C O

X

•«— * c_> a> -*-» co * o CC* -i— I fZj S t=- « — I

p s = * ]

s T-i O

ct3

ctS

co

CO;

c_» o! o

—

i 1 co; cd

C3 D V O CM

cvj

O CO

vo

CISI

cvj CVJ

O co

.

c i

-e O?

OJ vO OJ

V O

Q ■— 1 CO

CO o o

-g -col SI B q> -

< O

O J

CVJ

C V J V O C V J

CVJ

v o

mm

0.50

Boiling Point (°C,)________ mm mm mm mm

1.00

2.00

5.00

Keat of Vap or. Cal./g

10.00

Refractive Index_______ Calc. 20°C

197.0 196.0

211.0

225.0

2^5.5

262.5

61+

1

210.0 22^+. 5

2M-5.5

262.5

62

1.W22

Experimental 20°C

30°C

*+0°C

l.^f82i 1.^7«82""l.lf7lflf

solid

solid

1A 550

Molecular Refraction Found Theor.

Spec. Molecular ReVolume frac-lion Found Calc.

33^3 1+20A

119.9

118.7

solid

120.1

solid ^37.7

•

*+35-7

tr\ • O CVJ 0-

252.5

266.5

286.0

302.0

1+8

l.>+586 1M 7 5 lA5>to 1A505

196 A

196.2

.3323

153.0

166.0

179.5

199.0

215.0

51

1A550 1A513 l.Vv77

131.8

131.1

.3355 1+85.6

156.0

168.5

182.5

202.0

217.5

51

1 A 5 0 2 1.1A 91 l.¥t55 1.^18

131.7

131.6

.3336

19^.0 207.5

222.5

2^3.5

261.0

65

1.5087 1.5081 1.501+5 1.5010

108.6

107.8 3.161

36V.3 36^.3

1A560 1A522 1 A W

133.0

133.1 .3238

W .2

5^.67

216.2

lAl9*+

00 • 0

239.5

715.0

-

W 7.0

to ± 0.3$>. oils;

Viscometers were calibrated using standard

the constants

in sec./stoke appear in Table II.

The constants are referred to water as standard, v i s ­ cosity taken as 1.007 ce. ±.005 cs. at 68 °F. tures wer e maintained to ± 0.05°F.

Tempera­

in the ba t b s used for

the v isc o s i t y and d ensity measurements. In Table II are listed the average efflux times in seconds w i t h the number of the vi sco met er used for each measurement. Calibrated stop watches read to 0.1 second w ere used.

Extrapol ate d values wer e obtained from the ASTM

standard viscosity Chart D. The absolute visco sit y at each t emp era tur e was calculated b y m u l t i p l y i n g the kinematic v i s c os ity by the density at the co rresponding temperature. Density:

Densities w e r e determined at the same tempera­

tures as w e r e the viscosities.

Pycnometers,

standardized

w i t h triple- dis til led water and re qui rin g ap proximately a 5 ml.

sample were used.

buoyancy,

The densities,

corrected for air

are accurat e to ± 0 .0001 g./cc. The weights and volumes of the p ycn ome ter s,c or­

rected weights of the loaded pycnometers, b u oya ncy corrections,

and the air

are listed in Table II.

Table II Viscosity and Density Data PSC No.

Viscometer Viscometer Constant No. sec./stoke

Efflux Time sec.

Pycn. No.

Pycnometer Weight g.

Pycnometer Volume cc.

Loaded Pycnometer We ight g.

Air Buoyancy corr. __g./cc. xlO5

3 2° F 152 153 182 183 18k 196

ma

- _

•

**51 a 375 A 380 A b5l A

■

-

—

•

17*293 367.66 187.77 17.293

-

523.9 5 ^ .2 501.8 ^75.0

_

—

-

27 >+1 -

13.500*+ 1*+. 6393 -

-

-

-

-

.-

-

-

5.1219 5.2832 —

17.7061+ 18.9538 -

21 22 -

68° F 152 153 182 183 l8*f

196

' _

390 236 301 380

A A A A

■

125.58 821.6 1110 188.05

■

-

■

567.3 338.7 689.0 653.9

•

13 27 *fl 36

-

8.888'+

13.5001+ 1>+. 6393 l i+ ^ W

-

- -

^.5123 5.1225 5.2837 5.1652

12.5895 17. 6^23 18.8873 19.2063

21 23 23 6 t

100° F

152 153 182 183 iSb

196

1^1 275 375 280 301 380

A A A A A A

5208 • 26o6i5 368.72 1621. ^ 1111.5 188.29

63H .I ^32.7 U-75.2 295.8 273.9 178.3

27 32

13. 5oo*f l*f.if006 IkM kS

27 25 26

13. 500^ 13.^316 13.8575

5.1231

5.2302 5.0686 5.1231 5.2957 5.0907

17.8100 18.6973 18.9671 17.5850 17.6293 18.6032

18 21 22

23 2l+ 7

Table II - Cont. Viscosity and Density Data PSC No.

Viscometer No.

Viscometer Constant sec./stoke

Efflux Time sec.

Pycn. No.

Pycnometer Weight

Pycnometer Volume ce.

Loaded Pycnometer g.

Air Buoyancy g./cc. xl05

l40° F 152

153 182

183 184

196

175 202 325 252 202 202

A A A A A A

10,71^

8121 776.73 3801.2 8121 1113.3 -

7**3A

724.2 317.2 328.7 864.5 331.0

27 27 13 32 26

13.5004 13.5004

8 .888^14.4007 14.8191 13.8575

5.1238 5.1238 4.5142 5.2309 5.0411 5 .091k

17.7367 17.6371 12.4811 18.4979 18.7^2 18.53^6

19 21 22 24 25 8

5.2322 5.1250 4.51^2 5.2322 5.0426 5.0927

18.5958 17.5110 16.6966 18.3701 18.6204 18.4155

19 21 22 24 25

210° F 152 153 182 I83 184 196

175 A 202 A 275 A 75-:L 202 A 351 A

10,846 8146 • 2618.7 971^.1 8146 472.01

363.1 333.1 281.0 3^5.6 326.6 37^.6

32 27

501 32 38

26

14.4008 13.5004 13.9589 14.4007 14.8191 13.8575

8

12a

Kinematic Viscosity Index:

The K.V.I. was calculated from

the kinematic viscosities at 100°F. and 210°F. using the Dean and Davis Tables, ASTM D567-40T. 210°F.

is less than 2.0 c s . , the K.V.I.

ASTM Slope:

If the-viscosity at cannot be calculated.

The slope values were calculated from the

viscosity-temperature plots on the ASTM Chart D by dividing the vertical distance in millimeters between the kinematic viscosities at 100°F. and 210°F. by the horizontal distance in millimeters between the 100°F. and 210°F. Moleoular Volume:

lines.

The experimental molecular volumes were

calculated from the theoretical moleoular weights and the densities at 20°C. The calculated molecular volumes for the completely hydrogenated compounds were obtained from the atomic values of Kurtz and Lipkin?®. Refractive Index:

The indices of refraction w e r e determined

at 20.0°, 30.0°, and 40.0°C. with a Valentine Abbe-type refractometer,

calibrated with NBS certified hydrocarbons.

The indices were read with a precision of £ 0*00005 index units and reported to four decimal places. The calculated values for the completely hydro­ genated hydrocarbons were obtained b y the method of Lipkin and M a r t i n .?7

Specific and Molecular R e f r a c t i o n :

The specific refraction

was evaluated using the Lorenz-Lorentz equation:

r = specific refraction n = refractive index at 2 0°0 . d = density at 2 0 °C. The molecular refraction is the product of the specific refraction and the molecular weight. The theoretical molecular refract iozs were culated from the atomic values of Auwers*

cal­

and Eia e n l o h r ^ ® .

A value of 2.430 was used for the carbon atom because of the accepted change in atomic weight for this element. Boiling P o i n t ;

The boiling points were determined on 10

ml. samples in an equilibrium apparatus similar to that described b y Fenske^®. stirred.

The samples are mechanically

A modification permits simultaneous boiling

point determinations of two compounds.

Approximately

eight determinations in the 0.50 to 10.00 mm. pressure range were made for each hydrocarbon.

By plotting the

logarithm of the pressure against the reciprocal of the absolute temperature a straight line was obtained. the line,

the boiling points at 0.50,

1.00, 2.00,

10.00 mm. were interpolated and recorded. points are reported to 10*5°C.,

From 5.00,

The boiling

the approximate accuracy.

The experimental points from wh i c h the line was obtained are listed in Table III.

15 TABLE III Boiling Point Data Compound

Temp.(°C.)

Press.(mm. Hg)

Temp.(°C)

Compound

PSO 152

200.6 223.2 245.2 253.1 261.1

0.625 1.88 5.05 6.88 9.40

201.4 223.6 245.5 253.2 261.0

PSO 153

PSC 183

159.0 172.6 182.6 191.5 197.6 205.3 201.1 214.6

0.68 1.40 2.35 3.50 4.70 6.50 7.91 9.38

161.8 175.4 185.3 194.0 199.9 207.5 212.2 216.7

PSO 184

PSC 182

243.7 248.1 251.8 262.6 269.2

0.625 0.80 0.94 1.65 2.30

PSO 196

205.5 209.7 220.0 228.8 238.4 259.8

0.90 1.10 1.80 2.65 4.05 9.30

Heat of Vaporization:

The integrated form of the Clapeyron

equation iob

pa -FT-

=

AH - T i) 2.303R (T3 T1 )

was used to calculate the heat of vaporization from the boiling points at 0*50 and 10.00 mm.

The values are accurate

to 1 2f}0. Aniline Point:

The aniline points were determined according

to the A STM method D611-41T.

However, only 5 ml.

the hydrocarbon and aniline were used.

of bo t h

The miscibility

temperatures are reproducible to i0.1°C. Furfural P o i n t : Furfural points w e r e determined in the same manner as w e r e the aniline points.

The miscibility tem­

peratures are again reproducible to d0.1°0.

The furfural

was carefully dried and purified b y distillation, and then standardized against known hydrocarbons. M e lting Point. Heat of Fusion, and Per Pent Impurity:

These

properties were determined in a constant heat conduction calorimeter described b y Fischl®^.

Several recent re­

visions and additions have been made to physically strengthen and simplify the operation of the machine. change, replacement

The major

of the fragile thermocouples with

heavier copper-constantan duplex couples, necessitated

recalibration of the apparatus.

The new heat transfer

coefficient values, thermocouple calibrations,

and methods

of operation and calculation are included in a report to Professor Schiess ler®2-. The data for PSO 152, 1,4-di-n-deoylbenzene,

the

only compound for which these properties could be obtained are summarized in Table IV. The heat of fusion could not be determined for 1,4-di-n-decylcyclohexane, PSC 153, cis and trans isomers.

since it consists of

The point of complete melt,

deter­

mined in a modified melting curve apparatus, was found to be 38.7°C.

The compound was roughly separated into a

eutectic mixture and the trans isomer by filtration.

The

eutectic melted at 20.9°C and the trans isomer at 45.6°0. The three methyl-branched hydrocarbons, PSC 182, 183, and 184,

could not be crystallized, and the calor-

imetric properties were not obtained. PSC 196, 6-n-octylperhydrobenz(de)anthracene is also a mixture of cis-trans isomers. stallization from ether,

By fractional cry­

two solid geometric isomers

melting 97-98°C. and 69.5-70°C. were separated.

The

melting points were determined in a capillary tube.

No

melting point was determined for the liquid fraction which probably consisted of a mixture of cis-trans isomers

TABLE IV Melting Point.

Heat of Fusion, and Pur i t y Data £SC 152

I

II

Weight of sample (g.)

10.0842

10.0842

A r e a of fusion (mv. min.)

530.97

569.90

Heat transfer coefficient

0.840

0.840

Heat of fusion (cal/g.)

41.62

43.53

Heat of fusion (cal./mole)± 5$

14,925

15,610

T 50— 100$ melt (°0 .)

0.29

0.29

M e l t i n g point

29.0

29.0

2.3

2.3

( ± 0.1°C)

Impurity ( ± 0.2 mole $)

INFLUENCE OF STRUCTURE ON PHYSICAL PROPERTIES

An important aspect of the high molecular weight hydrocarbon research program lies in drawing generalizations regarding the effect of structure on physical properties. The compounds investigated and reported herein have made possible preliminary study of the following effects: 1 . The effect of center-cyclized chains 2.

The effect of methyl-branched isoparaffins

3.

The effect of the perhydrobenz(de)anthracene group on physical properties. Two of the new hydrooarbons permit further study

of the effect of hydrogenation of a phenyl to a cyclohexyl group.

Another in the methyl-branched series allows in­

vestigation of the effect of olefinic unsaturation.

Ob­

servations have been made and compared to those of earlier investigators. The names,

structures,

and a complete tabulation

of the physical properties of the six new hydrocarbons discussed appear in Table I in the preceding section.

Their

structures and properties together w i t h thoBe of previously prepared hydrocarbons used for comparison will also appear at the appropriate place in the discussion. The properties to be discussed are: viscosity at 100° and 2 1 0 ° F . , slope, boiling point at 1.00 mar., melting point,

density at 20°0. , refractive index (n2 0D), aniline

point, and furfural point.

Since the fundamental purpose of this work makes it desirable that a variety of hydrocarbon types be synthe­ sized,

the generalizations relating to structural and

physical changes are based on a minimum of data and should be considered as highly speculative.

OENTER-CYCLIZED CHAINS PSO 152 and 153, Fig.

1, are the second pair

in a C26 series to be prepared for studying the effects of the p o s ition of a benzene and cyclohexane group in a straight chain.

The pair previously synthesized, PSO 99 and 100,

Fig. 1, form the other extreme of the series.

Since the

center-cyclized chainB under discussion do not fit, at present, into a well defined series where structural type is maintained constant, a Ogg molecular weight series in w h i c h the structures are v a r i e d has been substituted in an attempt to point out the physical property characteristics of the center-cyclized chains by their relationships to other molecular types.

The struc­

tural transformations in the series involve cyclization of the end of a 2 6 - o a r b o n chain to phenyl and cyclohexyl groups, transposition of the rings to the center of the chain, a n d br a n c h i n g the chain by hanging the rings from a central car­ b o n atom.

Fig.

1 shows diagjawaatically the structural changes

involved in the series. 106, 99,

The five comparison structures

(No.

100, 82, and 78) were synthesized previously by

members of the group and used in connection with other prop erty-structure studies. The physical property variations accompanying the structural transformations in the series are shown g r a p h i ­ cally in Figures 3 through 10.

Values of the physical con­

stants are plotted against molecular type so that relative proper t y - structure effects are easily observed.

22.

Fig. 1 n-C 2 6 PSC 106 Parent Straight Chain

£ > C 20

End-cyclized

O

PSC 99

Cio-Q

-C 20

PSC 100

-C.o Center-cyclized

C i0- 0

PSC 152

-c >°

PSC 153

Cg-C-Cn

Ring-branched

6

Cg-C-Cxi

o

PSC 82

PSC 78

Fig. 2

PSC 152 and 153

■

10'

■O-c.o

w

„ _ c 26

PSC 82 and 78

Biat-branchla^

ParafflB-J>ra p g M n 6>

c8-?-Cn

o

c^-c-c^ c*

PSC 106

PSC 1

The physical property values for the compounds in the series are listed in Table V. An interesting similarity between ring-branching and paraffin-branching has been observed.

The two types

of branching are shown diagrammatically in Fig. 2.

The

broken lines in Figures 3 through 10 have been inserted for easy comparison of the processes; the isoparaffin appear

in Table V.

property values for

The comparison is

treated at the conclusion of the O26 series discussion. The following pages are devoted to the observa­ tions and tentative generalizations concerning centercyclized chains in respect to the other appropriate, mole­ cular types mentioned above.

Table V

Properties of Cemter Cyclized and Comparison Hydrocarbons PSC No.

Structure

n-C26

106 99

O

C 20

Boiling Absolute Viscosity Point ( centipoises) 1.00 mm 100°F 2io°y (°C)

Melting Point (°C)

Slope

Density 20°C (g./cc)

n

20

Aniline Point (°C)

Furfural Point (°C)

D

9.12

2.1+9

205.0

56.2

.67

.80*4-2

1.1+1+97

116.0

150.3

9.70

2.68

212.0

1+2.3

.66

.85^f

1.1+801

58.9

95.8

152

ClO-^^-CjLO

10.25

2.685

211.0

29.0

.68

.8530

1.1+821

70.2

100.2

100

^ ^ - C 2o

13.5

3.23

212.0

V7.9

.67

.8322

1.1+623

110.8

11+8.2

153

ClO-^^-ClO

13.61+

3.201

210.0

38.7

.67

.8331

622

111.6

11+7.1

82

Cg-C-Cn

11.71

2.56

196.0

17.9

.77

.8532

1.1+790

63.1+

97.8

13.37

2.77

199.0

.76

.8370

1.1+635

106.1+

li+i+.l

2.099

192.5

.75

.801+1

1.1+500

113.8

11+7.9

* 1A

A Cg-C-Cn

78 1

Cio-C-Cii •

8.225

0.0

C* 1

77

♦Calculated by the method of Lipkin and Martin.

VISCOSITY Over the temperature range studied,

end-cyclized

chains and center-cyclized chains have amazingly similar viscosity characteristics.

The aromatic analogues of the

two molecular types^moreover, behave much like the parent straight chain paraffin at 100° and 210°F. chains, however, ships.

Ring-branched

show varying relative viscosity relation­

Hydrogenation of a benzene ring incorporated in

the chain causes a much greater increase in viscosity t h a n does hydrogenation of a phenyl group hanging from a chain. The above generalizations are based on the follow­ ing observations based on the data in Table V and Fig. 3: 1.

Cyclization to benzene rings at the end and in

the center of a chain (W, X, and Y, Fig.3) results in only 6

and 12$> viscosity increases,respectively, at 100° F . At 210oF . such cyclization causes a similar 8$

increase in viscosity for both end- and center-cyclized chains. 2.

(PSC 106, 99, and 152, Table V.) The &fo increase in viscosity at 100°F.

resulting

from the shift of the benzene group from the end to the center of the chain (X and Y, Fig.3) is in agreement with 59 the observation of Mikeska who concluded that the vis­ cosity increases with the number of side chains if the number of paraffinic carbon atoms attached to a given nucleus remains unchanged.

However,

consideration of the

increased rigidity introduced by the benzene ring in the center of the chain, thus lowering the probability that the molecules could assume an optimum configuration for flow, would lead one to predict a larger increase in viscosity for this structural change.

Some justification for the reasoning lies

in the

facts that at the lower thermal energy level, 3 2 ° F . , the shift causes a 15$ increase in viscosity and at the higher energy level, 2 1 0 ° F . , the viscosities of the end- and center-cyclized chains are identical. 3.

If the benzene ring is suspended from the center of

the chain (Z, Fig.3), the viscosity is increased 14$ at 1 0 Q ° F . The same transformation results in a 5$ decrease in viscosity at 2 1 0 ° F . (PSC 152 and 82, Table V.) The phenomenon is an illustration of the hazards involved in making generalizations based on observations at o constant temperature. At some temperature between 100 and 210°F.

the viscosities of all three aromatic hydrocarbons

will be nearly identical, and one might conclude that the position of a benzene ring in a molecule has no effect on viscosity.

Indeed, the cyclohexane analogues of the series

illustrate precisely this effect. 4.

Inspection of the cyclohexane values (X, Y, and Z,

Fig. 3) show that at 1 Q 0 ° F . the viscosities for the end- and center-cyclized and the ring-branched chains are nearly iden­ tical.

At 210°F.

the relative viscosity relationship of the

end- and center-cyclized chains remains unchanged, but ring-

Fig. 3

27.

w 13 •H (j-itH WO o 00 p, 11 O O •H V)1—I-P

■H

G

^

£

9

Fig. !(■ » • 4JOO •Ho O G c\i . CD

txO

.8100 Fig.

6

CM c

n-paraffin

W

Cn (n-paraffin-isoparaffin) Y Z

branching causes a 13$ decrease in viscosity. 153, and 78, Table V.)

(PSC 100,

Such temperature effects on vis­

cosity are measured as ASTM slope and will be the next property discussed. 5.

The usual large increase in viscosity attending

hydrogenation of a benzene to a cyclohexane group may be observed in Fig. 3.

It is interesting to note that the

increase for the end- and center-cyclized chains is over three times that for the ring-branched chain, increases, respectively.

50$ and 15$

Inspection of the data in Table

V shows that the relationship is unchanged at 210°F. A S T M SLOPE j. A S T M slope

has replaced kinematic viscosity

index to a considerable extent as a measure of the viscosity-temperature characteristics of oils.

It has been

shown mathematically®® that the dependence of viscosity index on viscosity makes its meaning very uncertain where a large variation in viscosity is concerned.

Since the

A S T M slope is approximately the first derivative of log viscosity with respect to temperature,

it follows that an

increase in slope denotes a greater rate of change of vis cosity with temperature. -*■ The actual slope of the viscosity-temperature curve as plotted on the AST M Chart D. ASTM Slooe = vertical distance between viscosity at 100°and 310° horizontal distance between lQOO and 310°

The slight variations in slope for the parent straight chain and the four ring-in-chain compounds (W, X, and Y, Fig.4) have already been indicated in the pre­ ceding discussion of viscosity where it was observed that the relative effects for these hydrocarbons remained pr a c ­ tically unchanged over the temperature range studied. Ring-branching, however, leads to a much higher rate of change of viscosity with temperature for both the benzene and cyclohexane analogues. As observed by previous inveetigators, hydrogena­ tion of the benzene group has little effect on slope.

■-

DENSITY AMD REFRACTIVE INDEX Because of the fundamental relationship linking density, refractive index, and atomic constitution, namely, molecular refraction,

the properties are discussed to­

gether. The usual large increases in density attending cyclization and aromatization are shown by all of the cyclic oompounds in the series (Fig.5).

As would be expected,

the same trend is followed by the refractive shown in Fig.

index as

6.

Apparently the "p a c k i n g '1 abilities of all three aromatic structures (X, Y, and Z, Fig. 5) are nearly identi­ cal since only very slight density variations are observed. In the naphthene series, transfer of the ring from the end

to the center of the chain causes no change in density, while ring-branching leads to a .0039/g./cc. Again, as shown in Fig.

increase.

6 , the refractive index follows

the same general pattern as the density. data in Table V are examined closely,

However,

if the

it may be seen that

transposition of a benzene ring from the end to the center in the chain results in a .0014 g./cc. decrease in density and an inorease in refractive index of .0020 index units. The anomaly is particularly interesting since the same effect has been observed for the para substituted phenyl group in 72 8-p-tolylnonadecane and l,l-di-p-tdy3dodecane . Apparently, para-substituted benzene rings show an exaltation of the refractive index. Since 1 ,4-di-n-decylcyclohexane is solid at 20° and 3Q°C,

the experimental refractive index at 20°C could

not be obtained.

The value, 1.4622, used in the discussion

was calculated by the method of Lipkin and M a r t i n .77

This

method has been shown in previous studies to give values in good agreement with experimental. 20°0,

The refractive index at 73 calculated by the method of Ward and Kurtz , 1.4626,

is also in good agreement with the value used. MOLECULAR VOLUME AND MOLEOULAR REFRACTION Using the method of Kurtz and Lipkin7®,

it was

possible to calculate the iaolecular volume of 1,4-di-ndeoylcyclohexane.

^he value obtained (435.7)

is in good

agreement with experimental (437.7),

a deviation of 0,45$,

The molecular refraction of 1,4-di-decylbenzene, calculated from the atomic values of Auwers' (118.7),

and Eisenlohr

78

is also in good agreement with that found experi­

mentally (119.9).

The small exaltation has been shown to

be characteristic of conjugated double bond systems. BO ILING POINT In accordance with the general rule that cyclization raises the boiling

point, the center-cyclized aromatic

and naphthenic compounds show boiling point increases over the parent straight chain 7).

of 6° and 5 ° 0 , respectively (Fig.

It is interesting to note also that the deorease in

boiling point caused by branching overshadows the increase due to cyclization. Transposition of either benzene or cyclohexane rings from the end to the center in the chain causes only slight lowering of the boiling point. Boiling point variations attending hydrogenation of the benzene ring are small and variant in direction. M E L T I N G POINT The factors governing the changes in melting point with

changes in molecular structure are very elusive.

Even

the well lsnown rule associating higher melting point with * Carbon value of 2.420 used.

*

32

Fig. 7 -P

c O

215

■H CL,

(O o •o

205

O PQ Fig. 8 -P

G

•H O a, •SHP o «H 0) X -P

1CG =phenyl A =cyclohexyl

Fig. 9 -p 5 Co L, a) £

10Co O

80-

G

60

■

Fig. 10 -P

•GH o CL, o

o

115£ P*H

95n-paraffin

^ ^ - C 2o

C 10- ^ y c 10

(n-paraffin-isoparaffin)

w

Y

Z

increased symmetry appears to be violated here since the melting point of the more symmetrical, aromatic,

center-

cyclized chain is lower than that of the end-cyclized isomer as shown in Fig.

8.

Cyclization to both aromatic and naphthenic center-cyclized chains lowers the melting point in accord­ ance with the general rule for cyclization to non-fused rings. Since the cyclohexane analogue of the centercyclized chain is a mixture of cis and trans isomers, and the point of the last melt reported is probably a solution phenomenon rather than true melting, any discussion of the melting point would be unsound. A N I L I N E POINT In general,

it has been found that cyclization

results in a decrease in aniline point, as w o u l d be ex­ pected,

the decrease is much greater for the aromatic

series than for the naphthenes.

Inspection of Fig, 9

shows that the center-cyclized compounds bear out the generalization. The high aniline point of the aromatic centercyclized chain as compared to the end-cyclized isomer i-s not surprising since the anilinophilic benzene ring on the end of the ohain has better access to the solvent

than the phenylene group in the center.

It is interesting

to note that the cyclohexane analogues follow the same pattern,

but, as would be expected,

to a much less degree.

Ring-branching results in lower miscibility tem­ peratures with aniline, a phenomenon which has been shown to accompany branching of other types of molecules. FURFURAL POINT Previous studies have shown that the furfural point behaves much as the aniline point for compounds with a low percentage of aromatic or naphthenic carbon atoms, except that the miscibility temperature is displaced u p ­ ward 32° to 38°0.

Comparison of Fig. 10 with Fig. 9 shows

that the center-cyclized chains are normal in this respect. R INQ-B RANCHINQ vs. PARAFFIN-BRANCHING The two new hydrocarbons containing rings incor­ porated in a straight chain furnish parent

compounds for

the tentative evaluation of a new clustering effect,

i.e.,

branching of the chain by suspending a ring taken from the chain.

Comparison of the effects of ring-branching with

those of ordinary paraffin branching (Fig. 2) show that they are strikingly similar. In Figures 3 through 10 the property values of the C26 parent straight chain have been re-plotted a’ i point Y, and those of the branched paraffin (isoparaffin) at Z so that the effects attending paraffin-branching

could be compared directly with those caused by ring-branching A broken line connects the points representing the paraffin hydrocarbons bo that the slopes of the lines rather than the relative positions of the points can be compared; closer correspondence of the slopes of the broken and solid lines denotes greater similarity between ring-and paraffin-branching The apparent anomaly for the viscosity effects (Fig. 3) is due to the greatly increased rate of change of viscosity for the ring-branched compound over that of the parent center-cyclized chain (Fig. 4).

Inspection of the

data in Tsble V shows that at 210°F.the effects of ringand paraffin-branching are similar.

36 HE THY L -BR a Int0 HEP ISOPARAFFINS The two hydrocarbons,

2 ,2 ,4,10,12,12-hexamethyl-

7-(3,5,5-trimethylhexyl)tridecane (P30 184), and 3,2,4,15, 1 7 , 17-hexamethyl-7,12-di(3,5,5-trimethylhexyl)octadecane, (PSO 182) have made possible the study of multiple methylbranching at the high molecular weight level.

A third

methyl-branched compound, 2,2,4,10,l2,12-hexamethyl-7(3,5,5trimethylhexyl)6-tridecene (PSO 183), allows further study of the effect of olefinic unsaturation.

Since the three

hydrocarbons fall into two different molecular weight and symmetry classifications,

they have been associated with

two distinct comparison groups, series.

a 033 series and a 0^3

(Figures 11 and 12). In the O33 series (Fig. 11), a simple two step

branching process is shown in which the molecular weight and symmetry of the molecules have been maintained essen­ tially constant.

To do this it was necessary to estimate

the properties of a 033 isoparaffin.

Rather accurate es­

timations were possible (Table VI) by means of interpola­ tions in the property-structure curves for the tri-n-butyl, -hexyl, -octyl, by Project 42.74

and -decyl methanes reported previously The branched olefin is included in the

series so that the amazingly large property effects attend­ ing the-removal of two hydrogen atoms, an apparently small

Fig.

c9-c-c9

n-C 28

11

C2g Series C C c c c-9-c-c-c -C-C-C-G-C-G-C-C

I

Co

C-C

c c-c-c

‘

c c c c ->c-c-c-c-c-c-c=c-c-c-c-c1 A 1 c g c C-C C C-C-C

t

t

t

6

PSC 188

PSC 18k

PSC 176

multiple branched paraffin

isoparaffin

n-paraffin

multiple branched olefin

Fig. 12 C^.2 Series C

c

c

c

C-Ci C-C-C-C-C-C~C-C-C-C-C-C-C-C-C-C ------- > A

A

C-C

C-C

s

Q-(J-C

c

t See Table VII

c9-c-cu-c-c9* i

»

*

C-C-C

6

PSC 182 multiple branched paraffin * See Tab^e VI

1

isoparaffin

structural alteration, may be compared directly with the property effeots accompanying methyl-branching, a drastic structural change. Property-structure curves for the Cgg series have been plotted (Figures 13 through 19) so that the relative effects may be better visualized.

The numerical values

of the properties for the hydrocarbons in the series are listed in Table VI.

The melting point values of the com­

pounds have been omitted since none of the methyl-branched hydrocarbons could be crystallized. For the C4 2 series shown in Fig. 1 2 , the pro­ perties of an isoparaffin of comparable symmetry and mole­ cular weight to PSO 182 were estimated by adjusting the properties of the PSO to the

O5 Q isoparaffin, (Ci0“ /2 C-O 3-O (-C^q

molecular weight level.

Data for calculating

molecular weight effects are scarce at this level, and the values are not accurate.

However, they are believed

to be quite satisfactory for qualitative comparisons.

The

estimated values with the probable error of estimation are listed in Table VII. The property structure effects characteristic of the methyl-branched hydrocarbons at both the Cgg ancl C42 molecular weight levels and the effect of olefinic unsaturation are discussed in the following pages.

Table VI

Methvl-branched and Comparison Hydrocarbons Ct)p Series PSC No.

Structure

176

n-C 28

+

-

(Cg )3- c *

18if

rc c | t cccccc t c 3

183

c c \ c c c cc cc c = c c c c c c c 2 6

c

Absolute Viscosity (centinoises) 100°F 210°F

Density Aniline Furfural Point Point 20°C (g./cc.) C°c) (°C)

ASTM Slope

Boiling Point 1.00mm. (°C0

2.888

.6V

220.5

l.t+515

.8068

120.8

15^.7

10.5 2.30 *0.2 +0.02

.73 +.01

208.0 + 1.0

1A518 +.0003

.8068 +.0005

116.5 ± 0.5

151.0 + 0.5

11.1

20

n ■D

19.5^

3.023

.80

168.5

1.^91

.801+3

119.6

l*+6.6

lif. 55

2.700

.79

166.0

1.if550

.8088

110.7

137.9

'

•

+ Cx denotes a straight chain of x carbon atoms

-62

*This compound has never been synthesized. The properties listed have been estimated by interpolation of values of PSC hydrocarbons of the same symmetry

Table VII

Methyl-branched and Comparison Hydrocarbon Ci+2 Series PSC No.

Structure

5I

182

cc c c cccccc- C 6 -cccccc c c z z

(C9-)2 Cl

(-C,)2 t

Absolute Viscosity (centinoises) 100°F 210°F 10k.k

33 *2

8.288

k.6

± 0.3

ASTM Slope

Boiling Point 1.00 mm.

.76

252.5

.68

1 .0 2

277

±5

n

20 D

1.^75

1A591

± . 000?

Density Aniline Furfural 20°C Point Point (s./cc) (°c) (°c) .820*f

.3217

-.0 0 1 0

135.0

J35 - 5

* Cx denotes a straight chain with x carbon atoms ++

This compound has never been synthesized. The properties listed are those obtained by connecting the values for PSC 59 to the Ci*.2 molecular weight level.

above 160

Above

160

VI300SITY Although "branching of a straight chain to a symmetrical isoparaffin of the same molecular weight re­ sults in a slight decrease in viscosity (Fig. 13), it has been shown that simple branching of any segment of the isoparaffin invariably increases the viscosity to a slight extent .70

For example, the structural transformation from C- 0-^2 resulted in a 12 $ in-

Op-C-C1

°2

2

crease in absolute viscosity at 100°F.

In comparison,

effects of multiple methyl-branching are exceedingly large. As shown in Fig. 13, methyl-branching of the isoparaffin causes an 86 $ increase in viscosity at 100°F; at 210° the increase is 31$. At the O42 molecular weight level where four lege of an isoparaffin have been branched,the viscosity increase is 215$ at 100°F, and 80$ at 210°F. (Table VII). The effect of the olefinic bond is amazing. The minor alteration of removing two hydrogen atoms from the branched isoparaffin causes over one-half as much physical property change as the very drastic structural change involved in methyl branching.

Inspection of Table VI

reveals that the effect is about the same at 210°F. A possible explanation for the large effect is that the interactions among specific parts of the molecule

(in this case, let

us say, the neopentyl groups)

hibited when a double

bond isintroduced.

structural changes of the type X - C - X

X-C-Y

Y-C-Y

Y

Y

i

i

are in­

Forprogressive > X-C-Y ----- *

*

i

X

X

where X is, for example, a straight

8 -carbon chain and Y is a cyclopentylpropyl group, the

increase in viscosity has been shown to be exponential 91 and not linear with respect to structural change. If the divergence from linearity is attributed to interactions of' the groups attached to the central carbon, it is plaus­ ible that the ability of the groups to get together and form a more rigid (hence more viscous) molecule would be hampered when a double bond links one of the groups to the central carbon. The viscosity-temperature coefficients of the olefin and the branched paraffin are nearly equal (Fig. 14), indicating that over the temperature range studied the viscosity relationships of the two compounds remain about the same. ASTM SLOPE As has been found in previous studies, the rate of change of viscosity with temperature increases sharply with increased branching (Fig. 14).

The slope of the

methyl-branched compound is somewhat lower than might be predicted from a consideration of the increase attending

43 . Fig. 13 o

* m 18 «rt pti ^rl mo o 4t -> >»

OOP,

O O *rt m r-t +»

£ >

c

• .8060 « ho

S

n-paraffin

isoparaffin

multiple branched paraffin

multiple branched olefin

the transition from the straight chain to the isoparaffin. It is possible that the neopentyl groups tend to behave like cyclopentyl groups which are known to produce hydrocarbons with a low rate of change of viscosity with temperature. The relative change in slope from isoparaffin to methylbranched paraffin is the same at the 033 anc* C42 levels. The slightly lower slope of the olefin appears plausible in view of the interaction discussion concerning viscosity.

Since there are 'fewer interactions in force ....

in the olefin than in the paraffin, less are affected by changes in thermal energy, and the rate of change of vis­ cosity with temperature is lower. DENSITY AND R E F R A CTIVE INDEX Because of the fundamental relationship of these two properties pointed out in the preceding section, the density and refractive index are discussed together. It has been intimated in the discussions on vis­ cosity and slope that the neopentyl groups in the methylbranched hydrocarbons tend to behave like cyclopentyl groups. If this is so, the transformation from the isoparaffin to the methyl-branched paraffin might be considered as a com­ bination of multiple branching and pseudo-cyclization. multiple branching is known to increase density slightly

Since

and progressive cyclization markedly,

one might expect

the methyl-branched compound to be much more dense than the isoparaffin.

As may be seen in Fig.

16, the density

of the branched paraffin is actually about less than that of the isoparaffin.

.0025 g./co.

Apparently the mole­

cule approximates a "fuzzy" ball and adjoining molecules are unable to pack closely due to the essentially spherical symmetry.

Multiple branching at the C42 level, as shown in

Fig. VI, also causes decrease in density relative to the isoparaffin. When the ba ll is distorted by linking one of the groups with a rigid double bond, projections and indenta­ tions are formed by means of which the molecules oan approach more closely (a jig saw puzzle effect) and the density is greatly increased as seen in Fig. 16. Inspection of Fig. 15 and Table VII showsthat the relative changes in refractive indices accompanying the structural changes in the O28 series follow closely those observed for the density. MOLECULAR VOLUME AND MOLECULAR REFRACTION The molecular volumes of the two saturated methylbranched hydrocarbons, 2,2,4,10,12,l3-hexamethyl-7(3,5,5trimethylhexyl)tridecoane (PSC 184) and 2,2,4,15,17,17-hexamethyl-?,13-di(3,5,5-rtrimethylhexyl)octadecane,

(PSC 182)

were calculated by the method of Kurtz and Lipkin.7®

The

values are listed in Table VIII with those determined experimentally.

The calculated and experimental values

are in good agreement. The experimental molecular refractions for the two hydrocarbons above and FSC 183, the olefin correspond­ ing to PSC 184, were calculated from the atomic values* of Auwere*

and Eisenlohr7 8 .

The calculated and experimental

values listed in Table VIII, are In excellent agreement.

Table VIII _______ Molecular Volume_________Molecular Refraction E x p t 11 C a l c . Deviation E x p t 11 C a l c . Deviation

184

490.8

487.0

183

485.6

—

182

720.5

715.0

-3.8 — -5.5

131.7

131.6

- 0.1

131.8

131.1

-0.7

196.4

196.2

1 0 • 10

PSC N o .

BOILING POINT Branching of all types has been found to decrease the boiling point.

As would be expeoted multiple methyl-

branching causes a marked decrease in boiling p o i n t . ' As shown in Fig. 17, the methyl-branched paraffin boils 52° lower than the straight chain and 40° lower than the paraffin Although experimental data is unavailable at the high molecular weight level the C42 methyl-branched com­ pound is estimated to boil about 75° lower than the C42 ♦Carbon value of 2.420 used.

47

220

(°C)

Boiling Point 1,00mm.

Fig. 17

200 < 180

160

118 (°c)

Aniline Point

Fig. 18

lib

110

155 (°c)

Furfural Point

Fig. 19

n-paraffin

isoparaffin

multiple branched paraffin

multiple branched olefin

straight chain and 25° lower than the corresponding iso­ paraffin.

(Table VII) The boiling point of the C4g olefin is 2.5a

lower than that of the branched paraffin (Fig. 17). ANILINE POINT The decrease in aniline point attending branch­ ing to the isoparaffin in Fig. 18 is typical for most types of branching studied by Project 42.

In view of

this, the increase in aniline point caused by methylbranching is rather surprising.

Apparently the neopentyl

group is highly anilinophobic since 11-neopentylheneicosane has been found to exhibit the same effect.

Methyl-branching

appears to produce little or no effect on the aniline at the C42 level (Table VII) As would be expected the olefinic group lowers the aniline point. FURFURAL POINT In the Cgg series all of the structural trans­ formations give property changes in accordance with previous generalizations that branching and olefinic bonds decrease the furfural point

(Fig. 19).

The furfural points for bo th of the compounds in the 04:2 series were above 160° and could not be determined. (Table VII).

THE FERHYDROBENZfDli) ANTHRACENE GROUP In its study of fused-ring aromatic and naphthenic hydrocarbons,

the research group in this laboratory has

investigated the hydrogen-saturated forms of molecules containing the following ring systems: octane,

(3.0 ,0 )bicyclo-

indene, naphthalene, acenaphthene,

rene, phenanthrene,

anthracene,

indacene,

and naphthacene

A new hydrocarbon reported herein, PSO 196,

fluo-

4-0 72 » *

.

(Table VIII)

permits the study of an additional structure in the series, the perhydrobenz(de)anthracene group. It has been found that property-structure cor­ relations are best made on a "per cent carbon atoms in 72 40 rings" basis ' , hence a C25"‘°26 seri-es of hydrocarbons having increasing per cent carbon atoms in rings was sel­ ected to contrast the effects of the perhydrobenzanthracene compound.

The structures and properties of the com­

parison hydrocarbons and of the new compound are listed in Table VIII. Close inspection of Table VIII reveals the following facts concerning the property behavior of the perhydrobenz(de)anthracene nucleus:

On a per cent carbon

atom in rings b a s i s .the density, refractive index, boil­ ing point, aniline point, and furfural point of the perhydrobenzanthracene compound have values that would be predicted by interpolation in the appropriate columns

Table VIII

PerhydrobenzCde)anthracene and Comparison Fused-Ring Nuclei PSC No.

106

100

Structure

£Carl)on Atoms in Rings

Absolute Viscosity (centinoises) 100°F- 210°F

ASTM Slone

n-C26

0

9.12

2.k9

.67

( 3 “C20

23

13.5

3.23

.67

ko

17.30

3.5^7

lfl.1^

88.28

175

Density 20°C) fg./cc)

,80h2

20 n

D

Boiling Aniline Furfural Point Point Point 1.00mm (°C) (°C) (°C)

1M97

205.0

116.0

150.3

.8322

1A623

212.0

110.8

1*48.2

.70

.8681

I.V767

20^. 5

5.1^7

.78

.901^+

7.10^

.82

.9^32

101.0

1^2.5

95.7

l*t0.1

C15 125

196

166

e g o Ci2 a f tt Cfi 0 0 0 0 1 C8

68

69

312.5

11.23

.90

.9^50

1A 911 211+.5

1.5081

207.5

87.7

136.3

1.5123

211.5

86.6

132

FIG 21

PSC 166

of the table.

Since these properties of the perhydro-

benzanthracene hydrocarbon do not deviate from the pattern for the other fused-ring structures found by McLaughlin‘S , no further discussion of these properties is given here. The viscosity at 100°F and 210°F and the rate of change of viscosity with temperature,

on the other hand, are much

lower than might be expected from a consideration of the properties of the other compounds in the series. An explanation of the anomalous viscosity be­ havior may be derived from a comparison of the two hydro­ carbons 6— n-octylperhydrobenz(de)anthracene 9_n-octylperhydronaphthacene (pSC 160).

(PSC 196) and

The two molecules

are similar with respect to number of fused rings per mole­ cule, per cent carbon atoms in rings, tions,

and general symmetry (Fig. 21).

considerably, however,

intermolecular attrac­ They do differ

in their molecular dimensions.

Since

viscosity is a dynamic property and is a measure of the resistance to the passage of molecules through the liquid structure,

it appears logical that under a given stress

the molecule presenting a smaller dimension would offer less resistance,

i.e., have a lower viscosity, than a molecule

presenting a larger dimension. Measurements of the Fisher* Hirschfelder models show that in all possible configurations the low viscosity perhydrobenzanthracene compound presents a smaller dimension than the perhydronaphthacene compound. The measurements in millimeters for two extreme configurations ♦Fisher Scientific Company, Pittsburgh, Fa.

extended, (as shown in Fig. 21) and compacted .i.e. , rolled into the tightest ball possible, are listed below: Perhydrobenzanthra c ene Extended

124

x 200

Compacted

123

x 146

mm.

Perhvdronaohthacene 146

x 181 mm.

152

x 132

The lower rate of change of viscosity with tem­ perature for the perhydrobenzanthracene compound may also be attributed to its relatively smaller dimensions in con­ trast to the perhydronaphthacene molecule, by an extension of the speculation outlined above. The calculated molecular volume of 6-n-octylperhydrobenz(de)anthracene

(method of Kurtz and Lipkin7^)

is identical with that determined experimentally (364.3) The molecular refraction calculated from the atomic values of A u w e r s 1 and Eisenlohr

78

(107.8) is also

in excellent agreement with that found experimentally (108.6).

R I N G ANALYSIS METHODS

54.

NAPHTHENIO RINGS Several methods for estimating the naphthenio ftA ft*7 content of a completely saturated oil have been suggested0 0 * * 8 8 ,89 ^

^v nU «nen Wu6X6 u • 861 —

PA.

0.593d - 0.249 A

1 Qq 2 .8d - 142.8 1 ^ 0*^ 'T " 1

"h

A - - 10 5 x temperature coefficient of density derived from the molecular weight.

The values

of A are interpolated from a table listing molecular weight versus A. Values for weight per cent carbon atoms irr naphthene rings,

calculated by the two empirical methods,

are tabulated below wit h the per cent deviations from the theoretioal values.

The refractive index - molecular

weight m ethod is in much better agreement wi th theory than the density coefficient-density method for the.com­ pounds tested. Weight Per Cent Carbon Atoms in Naphthene R i n g s Compound

Theo.

n^D-M

23.1

22.8

68.0

65.8

Error

A - d

rfo Error

-1.3

19.2

-16.9

— 3.2

74.8

♦-10.0

1,4-Di-n-decylcyclohexane 6- n - 0 ctylperhydrobenz(de)anthracene

Three other methods for expressing naphthenio ring content, proposed by Fenske,

et . a l .,®9 were tested.

The calculated and theoretical values are tabulated below. 1 ,4-Di-n-decylcyclohexane

6- n - 0 ctylperhydrobenz(de)anthracene____

Calculated

Theory

Calculated

Theory

Wt.$ of naphthene rings fiq (equation 4 )

23,3

22.5

65.8

68.0

Number of rings pe r molecule ( equation 12 ® )

0.974

1.00

3.23

... 4.00

Number of carbon atoms occurring in ring structure (equation 7 ® )

5.93

6.00

16.2

17.0

With the exception of the number of rings per molecule calculated for the tetracyclio compound, the values are in good agreement w i t h theoretical. AROMATI C RINGS Both the refractive index-molecular weight method® 9 qrj

and the density coefficient-density method

have been

adapted to caloulate aromatic ring content of oils. The weight per cent carbon atoms in aromatic rings has been calculated for 1,4-di-n-decylbenzene. calculated and theoretical values are listed below. -

The

57.

1 ,4-Di-n-decylbenzen6 Calculated Wt. fo of aromatic rings (equation 43®9 )

20.0

Theory

21.2

Number of rings per molecule (equation 4499 )

1.00

1.00

Number of carbon atomB occurring in aromatic rings (equation 4589)

6.00

6.00

All values are in good agreement with theoretical

SYNTHESES

GENERAL SYNTHETIC METHODS

In this work the synthetic methods used have been governed not only by the type but also by the quality and quantity of the product desired.

The preparation of two to four hundred

grains of a hydrocarbon in the C25 to G5 q range, with a purity of 95 mole percent or better,

required the use of chemical

reactions that gave good yields and did not produce isomers or other materials of comparable molecular weight and struc­ ture through rearrangement or side reactions.

It is extremely

difficult to separate such mixtures at the high molecular weight level. The versatile Grignard synthesis, which gives un ­ ambiguous reactions in many cases, proved a useful tool. Preparation of halogen intermediates from which the Grignard reagents were derived, and of carbonyl compounds with which they were reacted,

constitute the bulk ox the work.

Con­

version of the Grignard product to the hydrocarbon was accomplished by dehydration in the case of alcohols,

and

by the Wolff-Kishner reduction or catalytic hydrogenation in the case of ketones. Careful purification of all intermediates by chem­ ical means, where possible,

and by distillation through all

glass fractionating columns of 35-40 theoretical plates

59. was carried out in order to simplify the purification of the final product. The hydrocarbons were purified by fractionation and selective adsorption of polar impurities on silica gel. The purity of successive fractions in each case was estimated by viscosity measurements.

All fractions whose viscosities

varied less than 0.25$ from the mean of the viscosity plateau were combined as pure hydrocarbon. The per cent purity of the hydrocarbons was estimated from mass spectral data and calculated from thermophysical data where possible. Descriptions and constants of any apparatus used for determining physical or chemical properties, and descrip­ tions of fractionating columns,

silica gel columns,

catalysts

and other synthetic and purification apparatus appear under SYNTHETIC AND PURIFICATION APPARATUS at the end of this section.

preparation

of

the

hydrocarbons

1 .4-DI-n-DECYLBENZENE DISCUSSION The p-di-n-alky lbe nze nes , reported in the litera­ ture, have been prepared mainly through Friedel-Orafts acylation or the Wurtz-Fittig synthesis. benzene,

The acylation of

followed by Wolff-Kishner reduction,

benzenes in good y i e l d .1

However,

gives monoalkyl

the acylation of the alkyl-

benzene does not always yield the para isomer alone.^

Many

side reactions capable of producing high molecular weight material are known to occur in the Yv'urtz-Fittig synthesis.^ The isolation of the desired para product from ortho and meta isomers,

or the separation of a mixture of hydrocarbons

at the Csg level would be a difficult problem. this,

In view of

it seemed advisable to avoid the more direct but am­

biguous methods,

and to employ a p-disubstituted benzene

with which an organometallic reagent could be reacted to produce an intermediate readily converted to the hydrocar­ bon. After several unsuccessful attempts employing various p-phenylene intermediates,

the synthesis of 1,4-di-

n-decylbenzene was accomplished by adding nonylmagnesium bromide to N-tetraethylterephthalamide, then converting the diketone to the hydrocarbon by means of the Wolff-Kishner reduction. The action of organoraagnesium compounds on

N-

diethyl amides has been studied by Maxim18 and Montagne2 2 ,

but the facts have not been correlated nor a mechanism pro­ posed. M e u n i e r ^ proposed a mechanism for the reaction of Grignard reagents with trimethylacetamide,

the intermediate

compound b eing a complex combination of trimethylacetonitrile, magnesium oxide,

and anhydrous magnesium halide.

He also

found that an excess of more than two mols of Grignard re­ agent is necessary for ketone synthesis, and that both .active hydrogens are replaced before the addition of the Grignard takes place. The use of over three moles of difficultly obtain­ able nonyl Grignard per amide group was unsatisfactory.

Some

consideration was given a procedure whereby substitution of the active hydrogen would be accomplished with ethyl Grignard, followed by the addition of nonyl Grignard to form the ketone. The method was not explored, however,

since the dialkyl

amide was found to give satisfactory yields of the diketone. Maxim-*-® obtained a 3 0 yield of p-dipropionyl b en­ zene by the action of ethyl Grignard on N-tetraethylterephthalamide.

From an intensive study of the reactions of

Grignards with N-dialkylamides he observed the following features of the reaction which make it particularly useful for the synthesis of p-diacyl benzenes: 1.

Tertiary amines,

formed from aliphatic N-dialkylamides

are not produced with the aromatic N-substituted compounds.

62

2.

Unsubstituted

N-dialkyl amides,

but

amides give better yields

from the

by r a ising the r eaction temperature, boiling

3.

ketone yields

latter i.e.,

ca n b e

than

increased

employing a higher

Bolvent.

Tertiary alcohols are formed, but only where an acid

or amide group occupies the ortho position to facilitate lac­ tone formation,

for example, N-d iet hyl pht hal ami de,

cr ~C6H5 ethanol-80^o ether mixture.

A total of 547 g. (2.0 moles)" of

N-tetraethylterephthalamide, m.p. 127-127.5°, was obtained, representing a yield of 83$ based on the terephthalic acid. The melting point reported by Maxim^-S j_s 127°. Two more identical preparations were made to synthesize sufficient N-tetraethylterephthalamide for the preparation of the diketone. 4.

Nonyl Bromide C9OH

-----—

---- ►

CgBr

To a 5 liter, 3 necked flask, equipped with a bubbling tube, thermometer, and condenser, was charged 2011 g. (14 moles) of 1-nonanol, n ^ D 1.4388, (Columbia Organic Chemicals Company).

The alcohol was heated to 120°,

and anhydrous hydrogen bromide (Dow) added through the bubbling tube until the flask showed no gain in weight after one hour of slow addition. After separating the aqueous layer, the bromide was washed twice with half its volume of cold concentrated sulfurio acid, once with an equal valume of 50$ methanol solution containing 2 $ ammonia, and once with an equal volume of 50$ methanol solution.

After drying over anhydrous

potassium carbonate, 2 6 2 6 g. of the crude bromide was ob­ tained.

On fractionation of this material the first five

fractions fumed badly.

The remaining bromide was rapidly

distilled through the column and again treated with sulfuric acid and the ammonical and plain water-methanol washes.

After

drying over anhydrous potassium carbonate, 2526 g. of the bromide was charged to column A— 5 and fractionated as follows: Fctn.

Still

Ool. 133°

139°

1

138-140

2-10

128-138 131

145

11

140-145

12-22

128-132

B.p.

Press.

105°

38 mm.

105-106 121

121-124

38-40 40 34-40

T.fft. 13 g. 148

n20D pink 1.4525-30

164

1.4534

2436

1.4541

23

155

140

118

32

2456

1.4570

24

160

120

91

6

2493

1.4565

Fractions 12 through 22 were combined yielding 2269 g (10,96 moles), 78.6% of nonyl bromide, n ^ D 1.4541. Fractions 1 through 11 were combined yielding 164.5 g of octyl bromide, indicating about 6 % of octyl alcohol in the original alcohol. 5.

p-Dideoanoyl Benzene

r!0 NEt8 0

Co:;Ets

G0 C9 c ^ gB r^

0 C0 C9

First Preparation Nonyl Grignard was prepared in the usual manner from 24.3 g. (1.0 mole) of magnesium and 207 g. (1.0 mole) of nonyl bromide in 400 ml. of dry ether at 35°.

A distillation

69 head was fitted to the flask, and the ether distilled and re­ placed by dry toluene until the flask temperature reached 109°. When the Grignard solution cooled to 100°, N-tetraethylterephthalamide, 110 g., (.4 mole), partially dissolved in 800 ml. of warm dry toluene, was added in five hours.

The

reaction mixture cooled slowly to 45° during the first half of the addition and became heterogeneous.

Heating to 75°

did not cause solution, and the remainder of the amide was added at this temperature.

The flask was transferred to the

steam bath and heated for 2 8 hours at 92° with stirring, then left undisturbed at room temperature for five days. Decomposition of the complex was carried out by cooling to 1 0 ° in an ice bath and slowly adding 20 $ sulfuric acid while stirring.

When the mixture became acid, the

flask was transferred to the steam bath and heated to 50°, with stirring, for 30 minutes.

All of the solid material

went into solution, and the layers separated cleanly.

The

organic layer was washed with 500 ml. of 10$ potassium car­ bonate to neutralize the excess acid.

The white solid separ­

ating from the toluene solution on cooling was filtered and recrystallized from ethanol. About 39 g. of diketone, m.p. o 107-108 , was obtained. The 2,4-dinitrophenylhydrazone melted 207.5-2-08°.

By further concentrating the liquor_to

one half volume, 7 g. more of the diketone was obtained. Concentration of the liquor to 200 ml. yielded 30 g. of the

original amide m.p. 127-128°.

Distillation of the remaining

liquor under reduced pressure (.3 mm.) gave 15 g. of a liquid boiling 130-150°, 5 g. liquid boiling 160-175°, and 16 g. of tarry residue. The diketone obtained represents 30$, and the re­ covered amide 28$, of the original amide. Second Preparation In a second preparation, 0.4 mole of N-tetraethylterephthalamide was reacted with 1.7 mole of nonyl Grignard, 100$ excess.

Other conditions were maintained identical to

those of the first preparation. The yield of diketone, 84 g . , melting 107-108°, increased to 55$ of theoretical. Third Preparation A toluene solution of 6.0 moles, 100$ excess, of nonylmagnesium bromide was prepared by the method described in the first preparation, and 414 g. (1.5 moles) of N-tetraethylterephthalamide was added in 4 liters of hot toluene at 95°.

When the addition was complete, the mixture was

stirred at 90° for 28 hours, then allowed to stand at room temperature for 24 hours. Michler's ketone tests were positive at the time 80$ of, the amide had been added, but were negative at the end of the addition. The complex was poured onto 5 kilograms of ice,

acidified with 2 0 % sulfuric for 90 mimites at 60°.

acid, and stirred vigorously

The layers were

separatedwhile warm

and set aside to cool. From the organic layer 280 g. of crude diketone was obtained.

Recrystallization from ethyl acetate yielded

260 g. of p-didecanoyl benzene, melting 107-107.5°. A 1 liter portion of the 4.5 liter aqueous layer, from the decomposition of the reaction mixture, was made strongly alkaline with potassium hydroxide.

Distillation

through a 14 inch Vigreaux column yielded 33 g. of diethyl­ amine, boiling 54-55°,

n20D 1.3870.

At

least 150g. of'di­

ethylamine can thus beaccounted for in the water

layer.

The organic liquor, 7.5 liters, was concentrated to 1300 ml. by distillation, and on cooling, 60 g. of di­ ethylamine salts separated.

After filtering, the salts

were neutralized, and 26 g. of diethylamine was obtained by distillation. The concentrated liquor was charged to column A-4 and fractionated at about 730 mm. Fctn.

Still.

B.p«

1-3

120-140°

4-7

163

147

19

8-12 ;

180

148

227

75-109°

Y/t. 592 g.

n2QP 1.41381.4090 1.4062

Remarks toluene mixture of 1-nonene and nonane nonane

Sgloff*50 reports 1-nonene, b.p. 146°, n20D 1.4161; nonane, b.p. 151, n2(^D 1.4056. The mixture of Cg hydrocarbons, 2 moles, represents 33 ^> of the nonyl bromide used.

The residue from the above distillation, 250 g . , was flash distilled from a retort up to a still temperature of 320° at 0.5 mm. mained.

A residue of 23 g. of viscous tar re­

The 194 g. of distillate was charged to the four

foot Hy-Vacuum column and fractionated. Fctn.

Still,

Ool.

B.P.

1-3

266°

248°

4-11

292

282

225

.45

86.0

12-17

294

285

266

.50

153.0

1.5015

18

320

303

280

.60

166.0

1.5016

180-204°

Press.

T .W t.

.7 mm.18.5 g.

n2Q P

1.5120 mixture of liquid and solid.

Residue about 25 g. A brief attempt to identify the various compon­ ents of the distillate was carried out as follows: Fractions 4-11, 65 g . , partly solid, were combined and filtered yielding 20 g. of a solid and 44 g. of liquid# On recrystallization from ethyl acetate the solid gave 2 g. of p-aidecanoyl benzene and 14 g. of a mixture melting 6080°.

Fractional crystallization of the mixture from acetone

yielded a ketone, melting 60-60.5°, 2,4-dinitrophenylhydrazone, m.p.82.5-83°, believed to be the keto amide resulting from Orignard addition to only one amide group.

Fractions 12-18, 80 g., did not give a solid 2,4dinitrophenylhydrazone.

The molecular weight, determined

cryoscopically in benzene was 500 and agrees well with that of a product resulting from the addition of three nonyl groups to the amide, possibly the olefin formed by the de­ hydration of the keto-tertiary alcohol.

The identity of

this product has not been ascertained. No unreacted N-tetraethylterephthalamide was re­ covered. The products isolated from the reaction are "tabulated below • Product

Wt.

Moles

diketone

261 g.

.68

nonane and nonene

240

.20

CO

176

45

1° based

23 33

H •

diethyla­ mine

80

O

olefin?

based on amide

11

2.4

81

10

Fourth Preparation Using the same method as outlined in the third preparation, 336 g. (1.2 moles) of N-tetraethylterephthalaraide was reacted with nonylmagnesium bromide, prepared from 114.5 g. (4.9 moles) of magnesium and 1012 g.(4.S moles) of nonyl bromide.

The flask was heated at 95° on

the steam bath, with intermittent stirring, for 50 hours. After decomposing, acidifying, and separating the aqueous layer, the organic layer was washed well with 3 liters of

74

1°jo HOI to remove the diethylamine. By cooling the organic layer to room temperature, 151,5 g, of crude diketone was obtained.

On cooling the

liquor in the refrigerator 57 g. more of the crude diketone separated.

Recrystallization of the material from ethyl

acetate yielded 190 g. of diketone, melting 107-108°, 41$ based on amide. Further working of the liquor gave no diketone.

1.4-Di-n-aecylbenzene C

0

9

c =o

A

K K gif fl s -H gO

C

9

g=i-::h3

A

;-TaOOHa

9

oh-:i=nh

A

y -----^ v1 --- * u 6=0 1

Go

o =i : - : . k 3

c h - g =h h

t

»

Co

i:aOCH3

c10

A

. ..

ry + C xo

Go

Autoclave Wolff-Kishner Reduction p-Didecanoyl benzene, 137 g. (.329 mole), 99 g, (1,97 moles) of 100$ hydrazine hydrate, 336 g. (6 moles) of sodium methylate, and 1800 ml. of triethylene glycol was charged to bomb 2-B, capacity 4392 ml.

The bomb was sealed,

and, while rocking, heated to 195-200° and maintained at this temperature for 21 hours.

After cooling to room tem­

perature, the bomb was vented carefully and the contents removed.

The vessel was washed with alternate portions of

water and hexane, the washings being added to the main

reaction mixture.

After diluting the reaction mixture

with an equal volume of water to render the hydrocarbon insoluble, it was extracted with four 1 liter portions of hexane.

The major part of the aqueous ana hexane layers

separated cleanly, but a stubborn emulsion persisted which was finally broken by acidifying with hydrochloric acid. Kexane extractions of the acidified material were added to the main hexane solution, about 5 liters total.

The hexane

solution was acidified with 800 ml. of 1:1 hydrochloride acid, and stirred while warming on the steam bath overnight. After washing twice with 500 ml. portions of water, the hexane solution was dried over anhydrous potassium carbonate, and passed through a 40 cm. column of silica gel.

It-was

then concentrated to 500 ml. and treated with 0.6 mole of freshly prepared phenyl Grignard to convert any remaining ketone to the tertiary alcohol, more easily separated from the hydrocarbon by fractionation and chromatographic ab­ sorption.

After two days of refluxing, a positive Michler’s

ketone test was obtained.

After decomposing the mixture

with water, and acidifying, the organic layer was separated, washed with 500 ml. of water, and dried over anhydrous potassium carbonate.

The hexane and benzene were dis­

tilled, and the residue charged to a Olaisen flask for farther distillation.

76. B. ID,

Still.

Fctn.

Press.

Wt.

a4 Uliu.

32 g.

Remarks biphenyl shown by mixed m.p.

120-300°

95-115(

235

218

.7

5

partly solid

300

250

.7

80

n20D 1.49301.5020

Residue 7 g. Fraction 3 was charged to the two-foot, open-tube Hy-Vacuum column and fractionated as follows: Col.

Fctn.

Still.

1

250-70°

2

268

237

3

260

4

B.p_. .

Press.

T.Wt.

n20D

.15 mm.

3 g.

200

.9

6

235

196

.3

9

264

236

195

.13

18

5

260

254

204

.13

27

1.4903

6

260

254

204

.13

43

1.4917

7

261

255

205

.13

58

1.4930

8

275

260

210

.13

67

1.4960

9

300

267

310

.13

70

1.4982

10

350

277

210

.13

74

1.5053

220-32° 175-98°

part sol

Residue about 5 g • On passing fractions 2 through 10 through a 20 column of silica gel, 65 g. of a liquid, n20D 1.490B,was obtained.

Considering this to be p-di-n-decylbenzene the

yield was .182 moles, 52$ based on the starting ketone. hydrocarbon was set aside for further purification with material from subsequent preparations.

The

Atmospheric wolff-Kishner Reduction A mixture of 193 g. (0.5 mole) of 1,4-didecanoyl benzene, 100 g. (2.0 moles) of 1005* hydrazine hydrate, 5 ml. of glacial acetic acid, and 200 ml. of triethylene glycol was charged to the two-foot, open-tube Hy-Vacuum column. The mixture was slowly heatedto 180° while the excess hydrazi. hydrate and the water}formed in the reaction, distilled.

The

temperature at the head of the column was not allowed to ex­ ceed 120°.

The flask; was cooled to 145°, and another 50 g.

(1.0 mole) of hydrazine hydrate was added through the top of the column.

Distillation was again continued to the same

temperature as above.

About 119 g. of the theoretical 136 g.

of excess hydrazine hydrate and water was recovered.

The

hydrazone solution, which solidified below 100°, was trans­ ferred hot to an electrically heated dropping funnel and added slowly to a mixture of 27 g. of sodium methylate and 200 ml. of triethylene glycol, heated to 200° in a 1 liter

flask under the column used in the preparation of the hy­ drazone.

The hydrazone was dropped directly into the flask

which was equipped with an extra neck for this purpose.

The

exit from the column led through a dry ice trap to a 12 liter gas collecting flask.

During the 3 hour addition

period and 12 hours of heating at 200°, over 27 liters of nitrogen’ was collected.

The exact amount is not known.

The theoretical amount of nitrogen corrected for temperature and pressure was 25.4 liters.

79. When cool, the reaction mixture separated into two clear layers.

After separation, the glycol layer was acidified

with HOI, diluted with 1.5 times its volume of water and ex­ tracted three times with 200 ml. of hexane.

The hydrocarbon

layer was washed twice with an equal volume of water, and the wash water then extracted with 200 ml. of hexane.

The hydro­

carbon and hexane washes were combined, concentrated to 500 m l . , and stirred vigorously for three hours at 70° with 300 ml. of 1:2 hydrochloric acid.

After separation, the organic

layer was washed and the combined water layers extracted- with hexane.

The hexane solutions of hydrocarbon were combined,

dried over anhydrous calcium chloride, then passed through a column of potassium carbonate.

The dry solution was again

concentrated to 400 ml. and reacted with about .75 mole of fresh phenylmagnesium bromide in 400 ml. of ether at 65° for 4 hours.

A positive Michler’s ketone test was obtained after

the heating period.

The Grignard was hydrolyzed with 250

ml. of 1:1 hydrochloric acid, washed with 200 ml. of water, and dried by passing through anhydrouB potassium carbonate, .after removing the solvent, the hydrocarbon was Claisen distilled as follows: ;tn. 1

Eress.

Still.

B.p.

100-190°

60-150°

.15 mm.

T.Wt. 2 g.

n20D biphenyl

2

230

202

.20

10

3-7

235

205

•10

157

8

255

245

.05

171

1.5060

9

265

250

.05

175

1.5162

Residue negligible •

m .p .ab ov e

Fractions 2 through 7, 155 g., represent an 86.5fo yield based on the diketone. Fractions 6 and 9 taken as the mono-tertiary alcohol from the addition of phenyl Grignard, l(4-n-decylphenyl)-l-phenyl-l-decanol, represents Qfy of the diketone. In a second reaction, 261 g. (.675 mole) of the diketone, 203 g. (4.0 moles) of 1006jo hydrazine hydrate, 7 ml. of glacial acetic acid, 36.5 g. of sodium methylate, and 600 ml. of triethylene glycol was used. the same as described above.

The method was

A total of 157 g. of the

theoretical 184 g. of water and excess hydrazine hydrate was recovered.

The theoretical corrected nitrogen volume

was 34.5 liters; 48 liters were collected.

No explanation

can be offered for the excess gas collected.

The total

heating time at 200° was 20 hours. After working up the product as described above, and reacting with phenylmagnesium bromide, the product was Claisen distilled as follows: Fctn.

Still.

1

200

CO I CQ

240

7

280

B.p,. 170 217-222 250

Press.

T. Wt.

.5

2

.4

210

.35

220

Residue 19 g. brown oil. The yield of crude hydrocarbon was 208 g., repre­ senting an 82.5‘jo yield based on the diketone.

81

The 418 g. of crude 1,4-dideca.noyl benzene from the three reductions was charged to the six-foot Hy-Vacuum column and fractionated as follows: Fctn.

Still.

Col.

B.p._

Press.

T. Wt.

1

212 °

210 °

194°

.63 mm.

2 g

2

231

208

194

.57

8-

3

226

204

193

.55

4-24

229

203

193

.50

359 ..

25

257

217

202

.45

376"

26

300

223

206

.45

390

14

Efflux times of the various fractions, determined with viscometer 141-A at 140°F, appear below.

The center

column lists the efflux times in seconds of the material as fractionated.

The right hand column lists the efflux times

after treatment with silica gel, in a 10" x 1/4" column, to remove polar impurities. Fctn.

As Fractionated

2—3

Gel Treated 359.5

4

358.1

)

5

359.1

) )combined

6

358.6

7

358.4

8

359.4

9

359.4

13

359.9

17

360.8

20

360.8

359.2

82 . Fctn.

as

Fractionated

21

361.3

22

362.2

23

365.3

24

366.5

Gel Treated

) )combined )

360.2

) )combined )

361.8

Fractions 8 through 16 plus one half of 17 were combined, passed through a 12" x 1/2" column of silica gel topped with a 3" column of activated alumina into a glass ampoule, and sealed in a nitrogen atmosphere.

The weight

of pure hydrocarbon was 149.5 g. The remaining 1,4-di-n-decylbenzene, 153 g. fractions

2 through

7, 18through 22 and a

half of 17 were

combined,

passedthrough thealumina-gel column

and hydrogenated to 1,4-di-n-decyloyclohexane.

(used above)

ATTEMPTED SYNTHESES OF 1.4-PI-n-ALKYLBENZKNSS DI8GUSSIQU Preceding the successful preparation of 1,4-Di-ndecylbenzene through the addition of nonylmagnesium bromide to N-tetraethylterephthalamide, the action of organometallic derivatives on several likely addends was investigated. The preparation of several hundred grams of a pure high molecular weight p-dialkylbenzene appeared, at the out­ set, to he a simple and straightforward task.

Even with the

exclusion of more direct methods such as Friedel-Crafts acylation and the Wurtz-Fittig synthesis, the difficulties of which are mentioned in the discussion of the preceding section, the addition of organometallics to properly substi­ tuted p-phenylene compounds afforded a highly probable path. The various addends investigated are discussed briefly.

All

gave unsatisfactory yields of the expected high molecular weight intermediate. Terephthalaldehyde The high relative reactivity of benzaldehyde toward organomagnesium compounds2 2 , together with the fact that Kauffmann27 prepared diphenyl-p-xyleneglycol in good yields through the addition of benzylmagnesium chloride to tere­ phthalaldehyde, indicated that the latter would be a likely intermediate. Addition of octylmagnesium bromide to terephthalyladehyde, however,

gave only a small yield of an inseparable

mixture in the expected molecular weight range. The synthesis of the aldehyde through the hydrolysis of a,a,a1,a ’-tetrabromo-p-xylene, following the procedure of Snell and v/eissberger-^, could not be accomplished sat­ isfactorily.

Yields of the tetrabromoxylene, from the six

direct brominations of p-xylene attempted, were less than half of that reported by Snell and Weissberger. Terephthalyl Chloride The addition of G-rignard reagents to acid halides may produce tertiary alcohols or ketones depending on the conditions employed

OQ

.

The use of organocadmiums for the

preparation of ketones from acid chlorides, introduced by Gilman‘S

and investigated thoroughly by C ason^»^2 , is de­

sirable because of the reluctance of the cadmium compound to react with the mono-addition complex to produce tertiary alcohols.

Although Oason found that the addition of aryl

cadmiumB to alkyl acid halides was superior, the addition of alkyl cadmiums to aryl acid halides has produced good ketone yields^2 Terephthalyl chloride, however, when reacted with di-n-nonyl cadmium yielded a small amount of p-didecanoyl benzene, 3$, a larger amount of p-decanoyl benzoic acid, 10$, and polymeric material.

In so far as the normal re­

action is concerned, addition to either of the acid chloride groups is slow, and there appears to be a tendency for the

mono addition complex to inhibit reaction with the remaining acid chloride group. The decreased activity of the acid chloride groups toward the addition of dinonyl cadmium suggested the possi­ bility that the Grignard reagent might add more rea-dily but stop at the ketone stage.

Unfortunately, even at 80°, the

reaction of nonylmagnesium bromide with terephthalyl chloride produced no p-didecanoyl benzene, and a high percentage of the acid chloride was recovered as terephthalic acid. Dimethyl Terephthalate The addition products from the reaction of Grignard reagents with esters are nearly always tertiary alcohols. The formation of ketones has been observed rarely34*33. Excellent yields of tertiary alcohols have resulted from the action of alkyl Grignards on methyl benzoate37*38*39, and tetraphenyl-p-xyleneglycol has been prepared by adding 36 phenyl Grignard to dimethyl terephthalate The amazing inertness of terephthalyl chloride to­ ward the action of nonyl Grignard, however, suggested the use of the more reactive addend, dimethyl terephthalate. It seemed possible that the activity of the diester might be sufficiently lowered that the addition would not pass the ketone stage. The reaction of nonylmagnesium bromide with di­ methyl terephthalate produced no p-didecanoyl benzene or

tetranonyi-p-xyleneglycol.

The product isolated is believed

to be the keto-tertiarv alcohol resulting from the addition of three nonyl groups to the diester. p-Phenylenediacetonitrile The addition of octylmagnesium bromide to p-phenylenediacetonitrile yielded only inorganic complexes and high boiling resinous material.

This is not surprising since the

action of Grignard reagents on benzyl cyanides is known to produce pyrimidine type compounds through condensation® and to form stable magnesium complexes7 of the type p-Phenylenediacetyl Chloride p-Phenylenediacetyl chloride with di-n-octyl cad­ mium produced an 18$ yield of 1,4-di(n-decanone-2)benzene. Although the yield could have been improved, the difficulty in preparing the acid chloride made the method impractical for this synthesis.

It is interesting to note, however, the

large increase in the yield of diketone as the acid chloride group is moved one carbon away from the benzene ring. (See the reaction of dioctyl cadmium with terephthalyl chloride.) p-Phenylenedimagnesium Bromide The use of p-phenylenedimagnesium bromide as an intermediate was also investigated.

In conformity with

the results of Gilman®, Pink®, and Houben^O, no evidence of the formation of the diGrignard was found.

EXPERIMENTAL p-Phenylenedimagnesium Bromide

Eastman Kodak p-dibromobenzene, 118 g.,(0.5 mole) in 300 ml. of dry ether was dropped slowly onto 24,3 g. (1.0 mole) of magnesium turnings and 200 ml. of ether, at 35°, in a graduated 2 liter, 3-necked flask equipped with a condenser, stirrer, thermometer and dropping funnel.

After

stirring the waxy brown-yellow reaction mixture for twenty minutes, titration of a 5 ml. aliquot revealed that 39% of the possible Grignard reagent had formed. An additional 200 ml. of ether was added and the mixture stirred for one hour.

After standing overnight, a

second titration showed 58% of Grignard reagent.

Because

of the large amount of waxy material present, it was im­ possible to remove a homogeneous sample, even though vig­ orous stirring was used while the aliquot was taken. In an effort to dissolve the resinous material, 300 ml. of ether was distilled from the reaction flask, and 250 ml, of dry distilled toluene added.

Much of the waxy

material dissolved, and another titration indicated 64% Grignard reagent.

The temperature of the flask was raised

to 75°, causing most of the ether to distill, and 400 ml.

more toluene vms added.

The mixture was cooled to room tem­

perature overnight, and the titration of an aliquot taken with vigorous stirring showed 60$ Grignard reagent.

After letting

the mixture settle, a titration of the clear upper layer in­ dicated 41°jo. Since the titrations showed varying percentages of Grignard reagent, and a literature survey indicated the forma­ tion of many complex c o m p o u n d s ® t h e

addition of pelar-

gononitrile was not carried out as planned.

The Grignard

mixture was carbonated, and an attempt was made to qualitatively identify any terephthalic acid formed.

None of the acid could

be isolated or identified. Terephthalaldehyde with Octvlmagnesium Bromide

GHOH G H O II

Intermediates: 1. p-Xylene Carefully fractionated Eastman Kodak (W.L.) p-xylene, n20D 1.4957, was used. 2. a.a.a1.a^Tetrabromo-p-xylene Following the procedure of Snell and .YeiBsberger^, a low yield, 22$, of a,a,a1,a'-tetrabromo-p-xylene was ob­ tained.

Although five subsequent preparations were made in

which several factors were varied in an attempt to raise the yield to 50-55$ obtained by Snell and Weissberger, the maximum yield obtained was 35$. All preparations were carried out in 3-necked flasks, of suitable size, equipped with stirrer, condenser, thermometer, and dropping funnel. iated boiling xylene.

Bromine was added slowly to the irrad­ After the reaction mixture cooled, the

tetrabromo-p-xylene was separated from the other bromination products by crystallization from chloroform, Quantities of reactants and conditions pertinent to the reaction given by Snell and Weissberger and those used for the six preparations reported are summarized in Table A.

Table

A.

Prep.

Moles Xylene

Moles Bromine

S & W

0.94

4.38B

1

0.94

4.38a

15

2

0.94

4.38a

6

3

0.94

4.38s

7.5

4

0.94

4.38°

8.5

5

0.32

1.45°

5.5

6

4.70

21.90A

A B0DEFG—

6-lQhrs

13

Light Type

Moles Tetrabromide

Yield Tetrabromid'

H H Ort* o o ol

Addn. Temp. •

Addn. Time

G

0.52

55%

140-150

D

0.21

22

155-165

D

0.00

0

D

0.19

20

145-155

D

0.24

25

145-165

E

0.06

20

140-158

F

1.03

22

150

Baker's technical Baker's technical shaken twice with 200 m l . of concentrated sulfuric acid. Baker's O.P. Two 200 watt tungsten lamps One ultraviolet lamp with reflector One 200 watt tungsten and one ultraviolet lamp One 300 watt tungsten lamp Baker's C.P. bromine was used in preparation 4

and 5 to eliminate the possibility of ring bromination due to iron contamination in the technical grade.

It is be­

lieved that the principle product from preparations 5 and 6 was hexabromo-p-xylene, since hydrolysis of the low melting residues yielded mainly terephthalic acid. No further investigation of the reaction was made because the six preparations produced sufficient a,a,a',a tetrabromo-p-xylene, 702 g. , for the following preparations.

3.

Terephthalaldehyde The aldehyde was prepared by the procedure of

Snell and Weissberger1 ' 1-. First Preparation To a 3 liter, 2-necked flask, modified Claisen. head,

fraction cutter,

equipped with a thermometer, and

ebullition tube, was charged 84.3 g. (0.2 mole)

of finely

powdered a , a , a ’,a’-tetrabromo-p-xylene (M.p. 169-170°) and 200 ml. of 85% sulfuric acid.

Vacuum from a water pump

was applied through the fraction cutter and the flask heated to 80° and maintained at that temperature until frothing subsided.

The temperature was then raised to 110° and main­

tained until the evolution of hydrogen bromide ceased. After cooling the flask to room temperature,

the

clB ar brow n reaction mixture was poured onto 600 g. of crushed ice. 100 ml.

The yellow solid was filtered, washed with

of cold water, and dissolved in 800 ml. of hot 10%

methanol.

After treating with 1 g. of Nuchar and cooling ,

a yield of 19.5 g. of white plates, m.p. 114— 115°, 73% of theoretical was obtained. Second Preparation The preparation of 38 g. (.28 mole)

of terephthal-

aldehyde, melting 114-115°, by the hydrolysis of 168 g.

(.4

mole) of a , a , a ’,a*-tetrabromo-p-xylene was carried out in the manner described above.

The yield was 71$ of theoretical. 4.

Octyl Bromide Octyl b romide was prepared from 3905 g.

(30.0 moles)

of DuPont octanol-1 b y the procedure described for nonyl bromide, page

67 •

The clear w ate r white product, was divided into two portions,

5433 g . , n

30

D 1.4530,

charged to columns A-5 and

A - 6 , and fractionated as follows: Column A-5 Fctn.

Still.

B.p.

1

122°

80-103°

Wt,

Press. 35 mm.

n2 QP

3 g.

1,4523

2- 14

127

107

40

1594

1.4527

15

130

-

10

1611

1.4503

4

1.4525

40

3822

1.4527

1

3838

1.4511

Column A-6 1

127

94-107

2-18

123

107

19

130

-

40

The 5375 g.(27.8 moles) 1.4527,

b.p. 107°/40 mm.,

of octyl bromide, n20D

represents a yield of 93$ based

on the octanol. The Reaction O c t y l mag nes ium bromide was prepared in the usual manner from 14.6 g. g.(.62 mole)

(.6 mole)

of mag nes ium turnings 119.7

of n-o cty l bromide in 350 ml. of dry ether.

93

The Grignard was stirred for one hour, and 33.5 g. (.25 mole)

of terephthalaldehyde was added in two and one

half hours at 35°.

The aldehyde was only slightly soluble

in ether or toluene at room temperature and was added in the solid state by was hin g it through the d rop pin g funnel stop­ cock wi th d;her.

Near the end of the addition the reaction

mixture bec ame very viscous, added to effect better overnight,

and 500 ml. of dry toluene was

stirring.

The mixture was stirred

then hea ted to 45° for one hour.

to r oom ternperature,

After cooling

the complex w as decomposed by pouring

it onto 800 g. of ice and 130 g. of ammonium sulfate. separation,

After

most of the ether and toluene was re moved from

the organic layer by distillation, to a 250 ml.

and the res idue charged

Glaisen flask for distillation. B.p.

Press.

Wt.

1

25-98°

30-2 mm.

-

2

190-200

4

7

3

20 0-220

4

38

Fctn.

g,

At a still temperature of 3 0 0 v , distil lat ion ceased.

All of the high boi l i n g material was a mixture

of liquid and solid material. erial charged,

About one third of the m at­

re mained in the still.

to distill the residue from a 100 ml. distillate was obtained.

An attempt was made Olaisen flask, but no

94

Du rin g the distillation, in the dry ice trap, dration.

4 ml. of water was collected

indicating the possibility of some dehy­

Fractions 3, 4, and 5 added bromine in carbon tetra­

chloride without the evolution of hydrogen bromide. The partial dehydration together w i t h the fact that the alcohol molecule

contains two asymmetric carbon atoms,

and is able to exist as a racemic mixture and a meso form, could explain the nonhomogerious nature of the product. D e h y d rat ion of the mixture was carried out in the following manner: To a 500 ml., stirrer,

thermometer,

3-necked flask,

equipped with a

.

and inlet and exit tubes w i t h openings

above the surface of the liquid for sweeping the flask with dry gas, w as

charged 43 g.

nonyl)benzene,

(.12 mole)

of the p-di-(l-hydroxy-

and 5 g. of finely powdered p ota ssium bi-

sulfate (Bakers C.P.fused).

S tirring and sweeping with

dry ni trogen w e r e mai nta ine d throughout the 21 hour de­ hydration period at 170-180°. The product,

37 g . , was filtered through a small

layer of silica gel to remove the potassium bisulfate, charged to the two-foot,

open-tube Hy-Vacuum column,

and

fractionated as follows: Fctn. 1

Still. 287-310°

Ool. 145-220°

B.p. 111-157°

Press. .2 mm.

T.Wt. 2 g.

2

316

230

195

8

8

3

330

270

165

1.0

15

A tarry residue w e i g h i n g 10 g. remained in the flask

95

All fractions were slightly yellow viscous liquids containing some high me lti ng white solid material. No attempt was made to separate the heterogenous mixture or identify the products.

Terephthalyl Chloride with Di-n-nonyl Cadmium

( C 9 ) s Gd

GOOH

G0C1

0GOOH

C0C1

Int ermediat e s : 1.

Terephthalic acid See page 65.

2.

Terephthalyl chloride The terephthalyl chloride was p repared as

described on page 65.

After removing the benzene,

acid chloride w a s flash distilled under vacuum.

the

In a

typical pr eparation the di stilled material was recry­ stallized fro m l igr oin yielding a total of 78 g. mole) of acid chloride melting 78.5— 79.5°.

(.38

This repre­

sents a 77l j> yield based on the acid. Cohen a n d P e r r i n g t o n ^ of 78°

report a melting point

96

3. HOHO +

Nonyl bromide CH3OH + HOI

a.

--->-

> OICH2OCH3

g9 00 H3

CgBr

Chloromethyl ether The chloro ether was prepared according to the

procedure outlined by Marvel and Po r t e r 1*3. To a 3 liter, 3-necked flask, flux condenser, thermometer,

and gas

equipped with a re­

inlet tube reaching to

the bottom, w a s charged 1000 g. of formaldehyde nical,

37 $ formaldehyde,

(12.3 moles) anol.

10$ methanol)

(Kerk,

corresponding to 370 g.

of formaldehyde and 100 g. (3.1 moles)

Ano the r 390 g.

(12.2 moles)

tech­

of m e t h ­

of methanol w a s added.

H y d r o g e n chloride was generated by dropping con­ centrated hydrochloric acid into concentrated sulfuric acid and passed into the formaldehyde-methanol solution.

The

addition w a s continued until no more HOI was absorbed.

A

drop in the temperature, which was maintained at about 30° by means of a wa ter bath,

also served to indicate when the

reaction w a s nearly complete.

About 4000 ml.

hy drochloric acid wa s required. arated,

of concentrated

The organic layer was sep­

dried with anhydrous calcium chloride,

charged to

column A — 7, and fractionated. Fotn.

Still.

Ool.

B.p. 55°

Press.

1

62°

62°

2

67

60

60

736

3

80

62

60

735

T.Wt.

729 mm.

n20P

9 g. 368 543

1.3972

The fractionated ether w e i g h e d 533 g. and represents a 54$ yield based on formaldehyde. b.

Nonyl me thy l ether Octyl Grignard was pre par ed in the usual manner from

177 g.

(7.3 moles)

octyl bromide,

of m agn esium and 1280 g.

page 92

, at 35°.

(6.62 moles)

of

The Grignard solution was

filtered from the excess magnesium,

used to minimize the

amount of octyl b r o m i d e in the product. The 533 g.

(6.62 moles)

of chloromethyl ether, pre­

pared above, was d ilu ted to one liter with dry ether and added to the Grignard at 40-45°. m i xture onto 2 kilograms of ice, separated,

After po uri ng the reaction the organic layer was

dried over anhydrous potassium carbonate,

filtered into a 5 liter flask.

and

The ethyl ether was dis­

tilled from the mixture on the steam bath up to a tempera­ ture of 80° at 300 mm. pressure leaving 926 g. of crude nonyl m eth yl ether,

a yield of 89$, based on the chloro—

ether. Nonyl Bromide After equipping the flask with a bu bbl i n g tube, thermometer,

condenser, and he ating mantle,

h e a t e d to 120°, and HBr

(Dow anhydrous) was passed into

the liquid for a total of 27 hours. evolved throughout

the ether was

Methyl b rom i d e was

the addition a nd passed up the hood.

A total of 1135 g. of HBr w a s used and the flask showed a gain in weight of 451 g.

The water layer was

separated,

and the nonyl

bromide purified as described for octyl bromide on page 9 3 . After d rying over anhydrous pota ssium carbonate,

it was

charged to column A-7 and fractionated. i ’ctn.

Still.

Ool.

B_.p •_

Press.

R.R.

T.Wt.

1

140°

1270

82-110°

40 mm.

15/1

12 g.

2

144

130

121

38

15/1

19

1.4530

3

146

131

125

39

15/1

26

1.4539

4-9

155

132

127

39

5/1

892

1.4541

10

185

130

124

36

T.T.

914

.1.4541

11

185

138

110

21

T.T.

928

1.4541

Fractions 3 through 11 w e r e combined.

n 20D

The pure

bromide weighed 900 g. and represented a. 66$ yield based on the octyl bromide. The Reaction To a 1 liter Grignard apparatus was charged 24.3 g.

(1.0 mole)

ether.

of m a g n e s i u m turnings and 250 ml.

A solution of 207 g.

in 100 ml.

of dry

(1.0 mole) of nonyl bromide

of dry ether was added at 35-45° in 5 hours. After sitting overnight,

the Grignard solution

was filtered into a 3 liter Grignard apparatus and 110 g. (.6 mole)

of powdered cadmium chloride (E and A Anhydrous,

O.P.) was added in two hours at 45°.

During the addition,

the reaction mixture became very viscous,

and 300 ml.

of

dry

ether and 600 ml.

of dry benzene were added to keep

the mixture fluid enough to maintain good the ad dition was completed,

stirring.

After

the reaction was stirred for

one hour and left set overnight. The terephthalyl chloride, dissolved in 300 ml. cadmium at 25°.

82 g.

(.404 mole) wa s

of dry benzene and added to the nonyl

A rise in temperature was observed at 'the

be gin nin g of the addition,

and the temperature was then

lowered by means of a toluene bath.

During the addition

the reaction w a s br ick -re d in color, but while for 20 hours at room temperature,

stirring

the color changed slowly

to deep yellow. The oomplex was decomp ose d by pouring onto ice and stirred for one hour.

The organic layer was separated,

washed three times v/ith 1000 ml. and twice with 1000 ml.

of 5fo pota ssium hydroxide,

of water to remove acidic material.

The last water wash gave no precip ita te when acidified with hydrochloric acid. The benzene-ether solution was evaporated to 20 0 ml.,

and,

on cooling,

a solid separated.

The solid

was twice rec rystallized from ethanol, and 5.5 g. of p-didecanoylbenzene, m e l t i n g 107-108°, was obtained. The b en z e n e was distilled from the liquor up to a still te mperature of 80° at 50 mm.,

and the residue distilled

through a heated Claisen head as follows:

Fctn.

Still,

1

150°

2

170

3

175

B.p,

Press.

1.

25 mm.

9 g.

1.4065

nonane

105

25

5

1.4505

nonyl bromide

145

1

3

45— 55°

n 2QP

Remarks

solidified at 15° probably ootadecane

The flask was equipped with a retort head and the remaining material flash distilled at 270-320°/.3. mm. About 5 g. of material melting 50-150° was obtained in the first attempt,

and 10 g. m elt ing 125-135°,

after re­

crystallization from ethanol, w as obtained in a second attempt.

A high bo i l i n g tarry residue, w e i g h i n g 48 g . ,

remained in the flask. The m ate ria l mel ting 125-135° was found to be an acid.

A 1.0 g.

sample was rec rystallized from 50 ml.

of benzene yi elding .5 g. of white plates me lti ng 144-145°. The material was dried well, and the neutral equivalent determined. I

II

Vft. Sample

.1064 g.

.1883 g.

Ml.

5.85

6.85

.100 N Base

Equivalents

.000585

.000685

Ne utr al Equivalent

274

275

The neu tra l equivalent obtained from this purified sample is in exoellent agreement with the keto acid p r o ­ duct, p- dec an oyl ben zoi c acid, molecular weight 276, resulting

from the reaction of only one of the acid chloride groups with the cadmium compound. The material balance of the reaction is poor and no explanation of the large amount of high boiling residue has been found.

A large amount of unreacted t e r e ­

phthalyl chloride m a y have been discarded as a cadmium or ma gne s i u m complex in the decomposition water. No other products w e r e

isolated or identified,

and no further research on the reaction was carried out*

Terephthalyl Chloride with Nonylm agn esi um Bromide

Int ermediates 1.

Terephthalyl chloride See page 65.

First Reaction No nyl m a g n e s i u m bromide was prepared in the usual manner from 12 g. g.

(.5 mole)

40°.

(.5 mole)

of magne siu m and 104

of nonyl bro mid e in 400 ml. of ether at 35-

The Grignard solution was transferred to a dropping

funnel and a dd ed to a solution of 103 g. (.5 mole) terephthalyl chloride in 400 ml.

of

of benzene at 30-35°

After stirring overnight at room temperature, the r eac tio n mixture was decomposed with ice,

neutralized

w i t h dilute hydroch lor ic acid, at 50° on the steam bath. a separatory funnel,

and stirred for 30 minutes

The mixture was transferred to

the clear aqueous layer drawn off,

and the milky organic layer w a s h e d with 500 ml.

of water.

The thick white aqueous layer was drawn from the organic layer and filtered yielding 40 g. of terephthalic acid (dimethylester m.p.

133-140°).

The benzene was distilled from the organic layer and the residue charged to a retort for distillation. About 10 g. of terephthalic acid sublimed at 3 0 0 ° , leaving 25 g. of tarry residue. The terephthalic acid recovered represents 6.0$> of the acid chloride used.

No attempt was made to recover

nonane or other low bo ili ng material from the benzene. No p- didecanoyl benzene or p-decanoyl benzoic acid was

isolated.

Second and Third Reactions Reactions similar to that described above were carried out at 40° a n d 80° using dibutyl ether as the solvent.

Again,

only terephthalic acid and high boiling

residues were obtained.

Dimethyl

Terephthalate

with

Nonylmagnesium

Bromide

Intermediates 1.

Terephthalic acid See page 65.

2.

Dimethyl terephthalate GOOH lJ 6ooh

Fifty grams

+

Hg304

c h 3oh

(0.3 mole)

f ^

t f 00 CH.

of terephthalic acid, 250 g.

of methanol (stock, ace tone free),

and 50 g. of concentrated

sulfuric acid were refluxed on th e steam bath at 70° for 24 hours.

In an attempt to b r i n g all of the ester into

solution, 250 ml. more methanol was added, but very little of the solid appeared to dissolve in the extra solvent. The reaction was then continued at 70° for another 24 hours. The hot methanol liquor v/as decanted from the solid and allowed to cool. by filtration,

The ester was separated from the solvent

the crystals were washed with water,

w i t h b'Jc potassium carbonate solution, mo re water.

then

and finally with

The liquor was returned to the r eaction flask

in order to extract more of the solid. By repeating the extraction six times,

then evap­

orating the liquor to one half its original volume, (.3 mole) of the ester,

58 g.

melting 138-138.5° was obtained.

The mel t i n g point of the ester reported by Cohen and IP o P e r r i n g t o n 115 is 140 .

Three recrystallizations

from a

mixture of methanol and water did not raise the melting point of the ester. The 58 g. of ester obtained represents a theo­ retical yield based on the acid. The Rea ction Nonyl Grignard was pr epared in the usual apparatus of 1 liter capacity, by dropping 106.5 g. nonyl bromide, mole)

in 100 ml.

of magnesium,

of dry ether,

(.51 mole) of

onto 12.5 g.(.51

in 250 ml. of ether at 40°.

The Grignard solution was dropped slowly into a solution of 50 g. in 600 ml.

(.26 mole)

of di m e t h y l t e r e p h t h a l a t e ,

of ether and 600 ml.

of dry benzene at 35-40°.

After stirring overnight at room temperature,

the reaction

mixture was decomposed with ice and neutralized with h y ­ drochloric acid.

The organic layer was separated and

dried w i t h anhydrous p ota ssiu m carbonate. Most of the

solvent was distilled at 110°/20 mm.

The residue was transferred to a retort and distilled at 0.3 mm. pressure as follows: Fctn. 1

Still. 120-140°

Wt. 15 g.

Remarks dimethylterephthalate

2

225

30

solid

3

250

20

liquid

No residue remained in the still.

The

from ethanol,

solid

fraction,

No.

2,

after

recrystallization

melted 84.5-85.5° and gave a 2,4-dinitro-

phenylhydrazone m el t i n g 150-131°. p - didecanoyl ben zen e m.p.

107-108°,

The product was not and no further work

t oward the identification of either the solid fraction, N o . 2,nor the liquid fraction, N o . 3, was carried out.

p-Phenylenedi ace to nit r il e with Qctylmagnesium Bromide Intermediates: 1. p-Xylene See page

88.

2 . a,a-Dibromo- p-x yle ne

Following the method of Adkinson and Th orp e-1-4 1500 g.

(14 moles)

of p-xylene was heated to 130° in a

5 liter, 3 -necked flask,

equipped with a stirrer,

denser,

thermometer,

and dropping funnel.

3000 g.

(18.8 moles)

of bromine

con­

7/hile stirring,

(Baker's C.P.) was added

b e neath the surface in twelve hours at 129-131°.

The

re act ion was then stirred for ten hours at 125°. The hot react ion mixture was transferred to a 3 liter di stillation flask, fractionated as follows:

charged to column A-5 and

Fctn.

Still.

B.p.

Press.

Wt.

Remarks

31-87°

13 mm.

322 g

p-xylene n 20D 1.4955

1

99-140°

2

144

100

13

1225

3

171

120

13

54

a-bromo-p-xylene unidentified liquid

A residue weigh ing 965 g. remained in the still The 1225 g. m.p.

(6.63 moles)

of a-bromo-p-xylene,

34.5-35.5°, represen ts 4 8 of the original p-xylene.

The 322 g. of recovered p-xylene represents 2 2% of the original charge. Recryst all iza tio n of the fractionation residue from 1500 ml.

of b e n z e n e yielded 354 g. of a,a'-dibromo-p-

xylene me lti ng 143-144.5°. a me lti ng point mother liquor,

(Atkinson and Th o r p e ^-4 report

of 143.5°).

Later crops, 350 g . , from the

probably tri and tetra brominated p-xylenes,

were found to be soluble in hot ligroin, while the symmet­ rical dibromide

is not.

The yield of a,a'-dibromo-p-xylene was 10$> based on p-xylene. 3.

p - P h enylenediacetonitrile

KG 2 ■Following the method described b y T i t l e y ^ , g.

(.77 mole)

of pot ass ium cyanide

(Baker's Analyzed)

150 v/as

dissolved in 110 ml. of water equipr;>ed with a stirrer,

condenser,

adding 350 ml. of ethanol, 80°, and 88 g.

in a 1 liter,

(.33 mole)

and thermometer.

and 285 ml. cooling,

After

the solution w as heated to reflux, of a , a 1-dibromo-p-xylene was added

at such a rate that reflux was iaaintained. xainute addition was

3-necked flask

completed,

After the 25

the condenser was inverted

of ethanol was distilled from the reaction.

a mass of white crystals,

On

together wit h a small

amount of yellow amorphous material,

separated.

The mix­

ture was twice extracted with 300 ml. portions of ether. On evaporating the ether, from 9 5 ethanol,

and recrystallizing the residue

13.5 g. of white crystals,

m .p. 95-96° was

obtained. The aqueous layer from the ether extraction con­ tained a large amount of white crystals.

About 300 ml.

of 95$> ethanol was added and the mixture heated to 76° while stirring.

On cooling,

96.5-97° was obtained.

13.5 g. of long needles,

The filtrate was evaporated under

v aouum to 350 ml. a nd a second crop, m.p.

96.5-97° was obtained.

point of 96°.

m.p.

3 g. of the dinitrile,.

T i t l e y 15 reports a melting

Further evaporation yielded only the yellow

amorphous material and inorganic salts. The total yield was 30 g. representing 57.5aJo of theoretical, based on the d i b r o m o - p - x y l e n e .

The

Reaction

Octylma gne siu m bromide was prepared in the usual manner b y the addition of 97 g. (See page92), 270 ml.

to 12 g.

(.5 mole)

of dry ether.

(.5 mole)

of octyl bromide,

of magnesium turnings

in

No magnesium remained at the end of

the reaction. To the Grrignard solution was added 30 g. of p-phenylenediacetonitrile, benzene. 35-57°.

dissolved in 350 ml.

(.19 mole) of w arm

Heat was applied to m ain tai n reflux temperature, The color of the reaction changed from a brick red

near the start to a cocoa-brown near the end. addition wa e completed,

After the

the condenser was inverted and

the ether distilled until the temperature reached 71°. condenser was returned to the reflux position, dry benzene w as added, 74°, with stirring, was 23 hours.

The

175 ml.

of

and the reaction was refluxed at

overnight.

The total rea ction time

The re act i o n mixture was cooled and poured

onto 500 g. of ice.

after stirring for one hour,

the

yellow emulsion was acidifi ed w i t h hydrochloric acid.

The

emulsion persi ste d and was finally br oke n by the addition of 1 liter

of ether.

with an amorphous

Clear aqueous and organic layers,

insoluble layer between, were obtained.

; The amorphous material w as dried and found to be largely inorganic.

The aqueous layer was discarded.

organic layer was distilled,

yielding,

The

in add ition to the

ether and benzene, about 10 ml.

of a liquid,

boiling 100-

110°/l5 mm. , and about 15 g. of a dark red resinous material w h ich remained as a residue in the distilling flask.

p-Phenylen edi ac ety l Chloride with Di-«n— octyl Cadmium.,

Intermediates; 1. p-phenylenedi ace ton itr il e One mole of the dinitrile,

164 g . , me lti ng 95.5-

96.5° was pre pared in five separate runs, by the method outlined on page 106 . 2.

p- Phe ny lenediacetic Acid To a 1 liter £rlenmeyer equipped wit h a condenser

was charged 375 ml.

of water,

375 ml.

of 98^ sulfuric acid,

and 10 g. of p-phenylenediacetonitrile.

The mixture

was b oiled for 4 hours over a B unsen burner.

About 12 g.

of small needles separated from the acid solution on cooling.

R e c r y sta lli zat ion from 1200 ml.

of b o i l i n g

water yielded 11 g. of long, slightly colored needles, m e lti ng 251.5-252.5°.

Melting points reported in the

literat ure are 240-241° by K i p p i n g 1 6 , and 244° by Zincke a n d K l i p p e r t 17,

The neutral equivalent

of the acid was determined

by titrating an accurately weighed sample, dissolved in 50 ml.

of ethanol,

Ml. EtGH g. Ml.

Sample of .498N NaOH

N e utral equivalent

with

standard sodium hydroxide.

I

II

50

50

Blank 50

.2298

.1974

0000

4.80

4.12

02

96.6

96.4

The theoretical ne ut ral equivalent

is 97.0

It has been found that a minimum of 750 ml. of 1:1 sulfuric acid is needed for the hydrolysis of 10 g. of the acid.

The nitrile will go into solution on heating

if less is used,

but on b oil ing a short time,

amount of m aterial comes out of solution, is not complete after four hours. zation,

a large

and the hydrolysis

Also, for recrystalli­

it has be en found that 100 ml.

of boJLing water is

needed to dissolve one gram of the acid. By the procedure described in the first paragraph, a total of fourteen runs were made converting 140 g.(.90 mole)

of p— p h e n yle ned iac eto nit ril e into 157 g.

of p-phen yle ned iac eti c acid, m.p. 251.5-252.5°.

(.81 mole) The yields

average 90$>. Further purifi cat ion of the acid,

such as bone-

bl ack ing in alcohol and repeated recrystallizations from water,

did give colorless crystals, but did not raise the

me lti ng point.

3.

p-Phenylenediacetyl Chloride To a 2 liter distillation flask,

equipped with a

Friedrick and two large bulb condensers in series with an ice trap, was charged 110 g. acetic acid, and 1520 g.

(.567 mole)

dried by heating to 90° at .5 mm. (12.8 moles)

was

to reflux,

in solution,

78°.

for two hours,

of thionyl chloride (Firaer and

A m ^ e n d , C .P . , not fractionated). brought

of p-phenylenedi-

The reaction mixture was

After three hours,

all of the aoid

and refluxing was maintained for 26 hours.

The ice trap connected to the exit from the condensers showed that only 5 ml.

of thionyl chloride was lost by entrainment

with the hydrogen chloride.

The reaction mixture was cooled,

and the thionyl chloride removed under vacuum, The acid chloride was then dissolved

70° at 20 mm.

in 500 ml.

of dry b e n ­

zene (dried by distillation and stored over sodium) and used in the following reaction. The Reaction Octyl Gri gnard was prepared in the usual manner from 43.6 g. moles) mole)

(1.8 moles)

of octyl bromide.

of magnesium and 347 g. Cadmium chloride,

(1.8

183 g.

(1.0

was added slowly at 45° and the reaction stirred over­

night.

It was necessa ry to add 500 ml. of dry benzene during

the addition to mai nta in proper

stirring.

The benzene solution of p-phenylenediacetyl chloride

(3 abotfe) was added to the solution of dioctyl

cadmium in two hours at 25°.

After stirring overnight,

the

complex was dec omp ose d by pouring onto three kilograms ofice, acidified with hydrochloric acid, hours.

and stirred for three

The cloudy yellow organic layer was separated and

concentrated by distillation from a Claisen flask under reduced pressure.

Aft er the benzene was removed,

17 g. of

octane distilled at 60-100° at 49 m m . , and 21 g. of octyl bromide distilled at 100-107° at 42 mm. pressure.

The d is­

tillation was disconti nue d and the residue cooled to room temperature.

The r esidue was dissolved in 1500 ml. of

ether and extracted twice with 100 ml. portions of 5$ potassium hydroxide.

After each alkaline extraction,

ether layer was washed with 1000 ml.

of water.

the

The water

washes were made alkaline by the addition of a few grams of potassium h ydr oxide and extracted with 500 ml.

of ether.

The two alkaline extracts were also extracted with 500 ml. of ether,

the ether

ether solution.

in each case being added to the original

The ether solution w a s evaporated by dis­

tillation on the s tea m b a t h to about 400 m l . , then simple distilled through a heated Glaisen head at A liquid fraction boi l i n g from 75-180°,

.5 mm.

pressure.

40 g . , was obtained

after w h i c h the bo i l i n g point rose very rapidly to 2500, w h ere a white solid fraction weighing 37 g.

distilled.

A

black t arr y residue,weighing 52 g . ,remained in the still. A sample of the solid fraction was recrystallized from acetone yielding a white solid m elting 69-70°.

Re­

crystallization from 95$ ethanol yielded n eedles melting

73-72.5°.

The identity of the material as 1,4-di(decanone-

2 ) benzene was established from the following facts: molecular weight of the compound, in benzene, was 379.

The

determined cryoscopically

It was insoluble in base and readily

formed a 2 , 4 - d i n i t r o p h e n y l h y d r a z o n e , m.p. other ketonic products are possible;

115-116°.

Two

the keto-acid, mol e­

cular weight 290, and the keto-tertiary alcohol,

molecular

weight 500. The 38 g.

(.1 mole)

of diketone isolated represents

a 17.5$ yield based on the p— phenylenediacetic acid, and, as a matter of interest, originally used.

a 0.7 $ yield based on the p-xylene

1. 4-D I-n-DECYL CYCLOHEXANE

;-:s

Vi'j i o

A 10

*

u ^ ;1 0

1,4— D i - n - d e c y l b e n s e n e , IBS g. , (.427 mole) was charged to the liner of bomb 1-B and hydrogenated over 10 g. of UQ P nickel at 2590 to 1880 psi at 153° in 30 minutes. The theoretical pre ssure drop at 153° was calculated from the perfect gas law

as follows:

Volume of

Bomb

1342 ml.

Volume of

Liner

219 ml.

Volume of

H ydrocarbon

190 ml.

V olume of

Free Space

933 ml.

Moles of Hyd rog en N eeded

3 X .427 = 1.281

Theoretical Pressure Drop = 1.28 X .082 X 426 X 14.7 .933

_

7Q 6 pei

The total hyd rogen absorbed was 710 psi at 153°. The liner was w a s h e d well wi th hexane and the nickel filtered from the solution in a 3" column of silica gel,

topped with a small amount

of gooch asbestos.

The

solution was charged to the six-foot Hy-Vacuum column,

the

hexane removed b y he a t i n g to 120° at 20 m m . , and the hydro­ carbon fractionated as follows:

115.

Press.

Fctn.

Still.

M.C.

B .p .

T. Wt.

1

228°

202°

178°

.25 mm.

1.5 g

2-6

226

197

179

.25

103

7

237

192

179

.25

123

8

256

194

179

.25

145

9

280

199

179

.25

153

Viscosities at 140°F. vari ed from 8.896 centietokes for fraction 2 to 8.962 centistokes for fraction 8 . Treatment wi th silica gel did not alter the v isc osi ty values. Such a var iat ion would he expected because of the geometric isomers possible. Fractions 2 through 8 , 124 g . , were combined and sealed in a glass ampoule under an atmosphere of pure nitro­ gen.

2 , 3 , 4 , 1 0 . 1 3 , 1 3 - H S X A M E T H Y L - 7 (3,5,5 - T R I M E T H Y L H E X Y L )6-TRIDECENE DISCUSSION The tedious preparation of highly b ranched inter­ mediates and the possib ili ty of skeletal rearrangements during the course of their subsequent reactions have dis­ couraged the synthesis of compounds such as the olefin prepared.

However,

the recently commercially available

3 , 5,5-trimethylhexaldehyde derivatives, prepared by the re­ action of diisobutylene with carbon monoxide and hydrogen, an 0X0 reaction,

has simplified the problem.

The alcohol, advantageous

3,5, 5-trimethylhexanol,

is especially

since the unbranched a and p carbon atoms

permit the formation of the bromide, using hydrogen bromide, without rearrangement. tertiary alcohols,

And, by the same token,

large

prepared from the Grignard and an

ester, m a y be dehydrated without

changing the carbon skeleton.

The olefin was prepared by adding 3,5,5-trimethylhe xyl mag nes ium b romide to ethyl carbonate and dehydrating the tertiary alcohol formed. The purity of the b ran c h e d bromide, prepared from DuPont alcohol, wa s established by comparison of the bo iling point, refractive index, and viscosi ty with those of a sample prepared by unambiguous reactions from Rohm and Haas 3,5,5-trimethylhexanoi c acid of greater than 98fa purity.

The sample w as prepared by reducing the ethyl ester

of the acid with lithium aluminum hydride,

and converting

the alcohol obtained to the bromide with anhydrous hydro­ gen bromide.

All of the constants were identical with

those of the bromide

from the DuPont alcohol.

A portion of the olefin was catalytically h y d r o ­ genated to the saturated hydrocarbon,

2,2,4,10,12,13—

h e x a m e t h y l - 7 (3,5,5-trimethylhexyl)tridecane. experimental

C C

G C

G C

CC C C G G h p B r

CCCCCCBr G

( S t O ) 3 GO

c c c c c c -COK

> t

»

>

C

0 G CuS04 .

pccccc -c=occccc t

0

I G

Intermediates: 1. Ethyl Carbonate U . S.I ndustrial Chemicals,Inc. carbonate,

(Refined)

ethyl

fractionated by D.Shellenberger of this lab­

oratory, w a s used. 2. 3 .5.5-Trimethylhexanol-l DuPont 3 ,5 ,5-t'rimethylhexanol,

PO 306 g. , n* jD

1.4320 was used without further purification.

Claisen

d i stillation of a sample revealed no high or low boiling impurities.

118

3.

3, 5,5— Trimethyl— 1— bromohexane Anhydrous hydrogen b rom ide was passed into 327 g.

(2.27 moles)

of 3 ,5, 5-trimethylhexanol,

further gain in weight was noted.

at 120°,

until no

The water layer was

separated and the br omide given the usual cold acid and methanol-water washes (page

67).

sulfuric

The crude bromide,

438 g . , was dried over calcium chloride and fractionated through the column A —2 as follows: Col.

B.p.

Press.

T.Wt.

n 20D

104-50

91-4°

28-9 mm.

4.6 g.

1.5426

30

8.8

1.4527

95

30

20.6

1.452-9

105

95

30

409.0

1.4530

160

100

88

18

425.5

1.4531

180

95

80

10

433.0

1.4559

ctn.

Still.

1

110°

2

110

105

95

3

111

105

4-8

110

9 10

Fractions 3 through 9, 417 g . , represent an 89$ yield of the bro mide based on the alcohol.

The viscosity

of the bromide at 20° was 1.731 centistokes. In a larger similar preparation,

4150 g.

of the pure bromide was prepared from 3167 g. of alcohol.

(20 moles)

(22 moles)

The yield was 91$ b ase d on the alcohol.

To

establish the purity of the bromide a sample wa s prepared from Rohn and Haas 3 , 5 , 5-trimethylhexanoic acid of high purity.

a " 3,5,5-trimethylhexanoi c acid A 652 g.

charge of the acid was fractionated at

20 mm. pressure in column A-2 as follows: Still.

Ool.

B.p.

1

152°

136°

130-2°

&0 CO

Efflux time 140° 141—A

Fctn.

2

152

136

132

19

1.4291

211.5

3

154

137

132

29

1.4288

217.0

4-11

159

136

133

562

1.4290

218.4-218.8

12

168

134

132

595

1.4290

219.1

n20D

T.Wt.

—

—

Unfortun ate ly the fractionation w as stopped prematurely,

and a residue of 43 g. remained in the still.

Oonstant viscosity fractions 4 thr oug h 12, 566 g . , were combined re pre sen tin g 85$ of the original charge. b. E t h y l - 3 ,5,5-trimethylhexanoate

CO

C O

II

1 1

OCOCOOOOH I 0

*--Et.3,S24..->

KQH

CCCCCCOOEt i C

Following the procedure outlined by M c L a u g h l i n ^ for the general prepa rat ion of esters with ethyl sulfate, 2 liters of absolute hydroxide,

and 474 g.

ethanol, 224 g. (3.0 moles)

acid was brought to reflux, 80°, flask,

A mmend (Pure)

of potassium

of 3 ,5,5-trimethylhexanoic in a 5 liter,

equipped with a thermometer,

and dro ppi ng funnel.

(4.0 moles)

condenser,

Then 924 g. (6.0 moles)

3-necked stirrer, of Eimer and

ethyl sulfate was added at such a rate as to

ma intain the temperature at 80° without external heating. The reaction was stirred for 70 hours at r ef l u x temperature, 80°.

The flask was then cooled to room temperature and the

mixture diluted with three times its volume of water. separating the layers,

After

506 g. of the crude ester was dried

over anhydrous potassium carbonate and charged to column A-2 «

for fractionation as follows: Fctn.

Still.

Col.

B.p.

Press.

T. Wt.

1

126°

121°

119°

60 mm.

10 g.

1.4200

2-3

203

202

199

735

28

1.4195

4-6

203

203

200

735

331

1.4195

7

250

203

200

735

397

1.4195

n20D

About 100 g. was lost w h e n the manostat failed, an d no yield of the pure ester cou ld be calculated

However,

the crude product represented a 91$ yield. c. 3 ,5,5-Trim.ethylhexanol-l

0 0

C C

i i

•

OOCOOCOOEt_________ ____v. 1

-Jls2

CCCCCCOH I C

c

About 1500 ml.

of stock anhydrous

tilled from calcium hydride

into a

equipped wi th an air stirrer, denser, an d a dropping funnel.

3

*

ether was

dis­

liter, 3-necked flask,

thermometer,

Fr iedric con­

When the distillation was

completed, all exits to the apparatus were connected to a sulfuric ac id and pyrogallol trap in series.

The ether gave negative

iodide tests for per­

oxides bef ore and after distillation. Li thium a lum i n u m hydride, H y d r i d e s , I n c . , was crushed 23.8 g.

(0.75 mole,

The m ixture wa s then solution. mole)

obtained from Metal

in a nit rog en atmosphere,

5 0% excess)

and

was added to the ether.

refluxed for 23 hours at 3 5 ° to effect

The h e a t i n g was discontinued,

and 186 g-

(1-0

of e t h y l - 3 ,5,5 - t r i m e t h y l h e x a n o a t e , diluted wi th an

equal v olume of dry ether, w a s a d d e d in one hour at a tempera tur e of 35°. After s t i r r i n g a short time, of 95% ethanol in 100 ml.

70 ml.

(1.0 mole)

of ether w a s ad ded slowly to

de compose the excess 0.25 mole of lithium alu mi n u m hydride. The complex w a s decomposed and ne u t r a l i z e d with dilute h y d r o c h l o r i c acid. white layers w ere obtained.

After sti rri ng for 3 hours, wat er The ether layer w a s separated,

dr ied over anhydrous pot ass ium carbonate,

and the ether re­

moved b y d i s t ill ati on on the ste am bath.

The alcohol wa s

fractio nal ly dis til led through a mod ifi ed Glaisen head as follows: Fctn.

Still.

B.p.

T.Wt.

n 3 QP

1

185

150-74

2

193

175

7.

1 .4311

3-6

193

182

105.

1.4320

7

198

182

117.

1.4320

8

210

175

125.

1.4320

9

230

165

141.

1.4320

2.

Fractions 3 through 9, 131 g. (.91 mole) represent a 91 °/o yield of the alcohol based on the ester. 3, 5,5-Trimethylhexyl-l-bromohexane Using, the procedure described above, 1- bromohexane was prepared from 130.8 g.

3,5,5-trimethyi

(.91 mole)

of the

alcohol. The crude bromide,

174 g . , was fractionated through

column A — 2 as follows: Fctn.

Still.

Col.

5.p.

Press.

T.Wt.

1

109°

105°

95°

30 mm.

3 g.

105

95

30

161

1.4530

90

82

14

173

1.4530

2-5

109-200

6

200

n 1.4530

Fractions 1 through 6, 173 g., represent a 92$ yield based on the alcohol.

The viscosity of the bromide,

1.731 centistokes at 20°, was identical wi th that prepared from the DuPont alcohol. 4.

2 ,2 , 4 , 1 0 , 1 2 , 1 2 - H e x a m e t h y l - 7 (3,5,5-tr imethylhexy1)7-tridecanol

First Prepara tio n A total of 589 g.

(2.84 moles)

1-bromohexane was added to 69 g. in 1 liter of ether at 35-45°.

of 3 ,5,5-trimethyl-

(2.84 moles)

in a conventional Grignard apparatus

After stirring for thirty minutes,

of a 5 ml. aliquot

of magnesium

titration

showed lOO/o Grignard reagent.

j£thyl carbonate, volume of ether w as

109 g. , (.925 mole)

in an equal

then added to the Grignard reagent at

40-45° in 1.5 hours.

The reaction mixture was refluxed at

40° for 14 hours, decompos ed by pouring onto

ice, and care­

fully neutra liz ed with 1:1 hydrochloric acid while vigorously stirring with a H irs hberg stirrer. separated,

the water layer

The clear layers were

extracted with 200 ml.

of ether,

and the combined ether layers stirred for 30 minutes with 50 g. of anhydrous po tassium carbonate to dry the solution and neutralize any acid present. tion, bath.

After filtering the solu­

the ether was removed by distillation on the steam The crude al cohol was charged to a one liter distilla­

tion flask and distilled through a Glaisen head as follows: Fctn. 1

Still. 100-35°

B.p. 40-75°

Press. .8-.5 mm.

Wt.

n 20D

14

colored

2

155

105

.35

29

it

3

170

135

.35

48

1.4452

4

172

152

.30

64

1.4524

5

173

154

.30

96

1.4550

6

172

155

.15

129

1.4558

7-11

175

337

1.4560

12

185

359

1.4560

155-65 158

.30-.50 .20

Fractions 4 through 12 wer e charged to the sixfoot Hy- Va c u u m column and fractionated as follows:

Fctn. 1

Still.

Qol.

B.p.

Press.

187-88° 161-84°'93-119® 1.1 m m

T.Wt. 7 g.

n3 Q P

Efflux Time 3 4 0 —A 140°F.

—

—

2

198

183

154

1.0

10

1.4540

-

3

199

183

171

1.0

14

1.4550

—

4

200

183

176

1.0

19

1.4552

—

5

196

183

176

.95

38

1.4557

307.3

6

199

182

177

.95

55

1.4555

316.1

7

199

182

177

.95

73

1.4560

326.5

8

199

182

177

.95

91

1.4560

328.3

9-13

197

182

176

.90

261

1.4560

14

193

180

173

.75

291

1.4558

327.2

15

234

210

173

.75

302

1.4560

—

330.3-.7

Fractions 5 through 15 represent a 75% yield based on ethyl carbonate.

Fra ction 12, 35 g . , was sealed in a glass

am p o u l e under n i t r o g e n for physic al pro perty determinations. Se cond P r e p a r a t i o n A Grignard solution was prepar ed in the usual mariner from 170 g. moles)

of m a g n e s i u m and 1449 g.

(7.0

of 3,5,5-trimethyl-l-broinohexane in 2 liters of ether

at 40-50°. b onate

(7.0 moles)

A solution of 236 g.

in 500 ml.

(2.0 moles)

of ethyl car­

of ether was then a dde d at 40-45°,

and

the r e a c t i o n m ixture w a s r e f l u x e d at 40-45° for 48 hours. i After d e c o m p o s i n g the complex by po uri ng onto ice, ne u t r a l ­ izing w i t h 1:1 h y d r o c h l o r i c acid, the ether layer w a s

and s tirring for one hour,

separated a n d dr i e d with anhydrous

sec.

p o t a s s i u m carbonate.

The ether was removed by distillation,

and the crude alcohol wa s rapidly Olaisen distilled at 1.0 mm.

pressure. The 784 g. of distilled alcohol ' w as charged to th
of the molecules contained an active hydrogen, and about 20 ^ contained a functional group which added the Grignard reagent, probably ketone.

148 Fractions 3, 4 and 5, 137 g. , were dissolved in acetone and cooled strongly, yielding 43 g. of crude octylbenzanthrone containing some of the oil.

Recrystallization

from acetone gave 30 g. of pure ketone. The 72-72.5°,

overall yield of octylbenzanthrone, melting

was 221 g . ,42$ based on benzanthrone. The

residue was again distilled through a Claisen

head as follows: Fctn.

Still.

B.p.,

Press.

T.V/t.

1

240

220

0.3

4

2

245

228

0.3

15

3

250

240

0.3

33

4

270

245

0.3

42

Active hydrogen determinations showed that fraction 3 contained about 48$ active hydrogen and 6$ ketone.

The material was undoubtedly a mixture, and the

separation of the components and their identification was not attempted. Reaction of Benzanthrone with n-Hexyllithium

066 14

0

As a matter of interest, 69 g. (0.3 mole) of benzanthrone was reacted with approximately 0.4 mole of

n-hexyl lithium in pentane at 30-35°.

The oroauct was

distilled yielding about 40 g. of benzanthrone, probably unreacted because of solubility conditions, and 20 g. of a viscous red liquid, boiling 250° at 0.1 mm.

Recrystall­

ization of the oil from acetone yielded 8 g. of a yellow solid melting 79-79.5°.

The material was found to contain

0.15 ±.03 atom of active hydrogen and to add 0.95 ±.05 mole of Grignard per mole. Since the alcohol that would be formed from a 1 ,2 -addition of the hexyl lithium would show a high per­

centage of active hydrogen, and the values correspond with those of 6 -n-octylbenzanthrone, the material was assumed to be 6-n-hexylbenzanthrone, resulting from a 1,4addition. 6 -n- 0 ctvlperhydrobenz(de)anthracene

First Preparation To the liner of bomb 1-A was charged 68.4 g. (0.2 mole) of octylbenzanthrone, 90 ml. of decalin (treated with U0F nickel at 2200 psi at 195° to insure complete saturation) 7 g. of U0P nickel, and 7 g. of W-6 Raney nickel.

The Raney nickel was prepared by N.R.Eldred of

this laboratory, and had been stored in the refrigerator under ethanol for several months. A total of 1810 psi of hydrogen, calculated at 155°, was taken up at 150 to 250° and 1900 psi.

It was

necessary to charge hydrogen to the bomb from time to time to maintain high pressure.

The hydrogen absorbed corres­

ponded to 1.33 moles of the 2.00 theoretically required. Calculations of the moles of hydrogen adsorbed are shorn below: Volume of sample

80

Volume of solvent

90

Volume of catalysts

ml.

5

Volume of liner

159

Volume of bomb

710

Volume of free space

380

1810 x 0.380 ._.. 14.7 x .082 x 428

- 1.33 moles of hydrogen absorbed

On removing the product, the ca.talyst was found to be agglomerated and was removed by filtration.

The

decalin solution was dried with calcium hydride, filtered, and returned to the bomb with fresh catalyst.

An additional

690 psi, (0.75 mole) of hydrogen, calculated at 20°, was taken up at 2600 psi.

Most of the absorption occurred at

2 0 ° with the shaker off, and the hydrogenation was com­

pleted at 2 0 0 °. The bomb was cooled and the contents filtered through one inch of silica gel to remove the catalyst. The solution was Claisen distilled as follows:

'ctn. -

Still. 80°

B.p.

Press.

60°

T. Yft.

3 mm.

decalin

1

210

200

0.2

12

2

216

204

0.25

29

3

216

208

0.25

43

4

230

205

0.25

58

All fractions partially solidified on cooling. Fractional crystallization from ether yielded three com­ ponents, two colorless solids melting 97-98° and 69.5-70°, and a colorless liquid. In order to obtain a quantitative measure of the benzenoid structure in the molecule, the ultraviolet spectra of the three components were determined.

A Beckmann spec­

trophotometer calibrated against the hydrogen spectrum by Carl Pitha* was used.

A slit width of 0.5 mm. and a cell

length of 1 .000 era. were used throughout the determina­ tions.

Solutions were prepared by weighing the sample

into a volumetric flask and making up to volume with silica gel treated Rohm and Haas isooctane at 20°. Solid - 69.5 - 70° Concentration —

0.0476 molar

This component showed no absorption maximum from 4000 £ to 2140 £ and was nearly transparent over the whole range at this concentration. *AEC Fellow - The Pennsylvania State College

Solid -

97.5

- 9 8°

Concentration —

0.0500 molar

The absorption maxima with their corresponding molar extinction coefficients are listed below.

b

£

2900

0.28

ft

2604

0.88

2544

1.10

2490

1.04

2430

1.08

The maxima for tetralin in hexane reported byMorton4® lie at 2670 and 2740 for benzene lies at 2700 &;

£ = 630.

The maximum

€ = 500. - Jones4'**.

The ratio of the molar extinction coefficients indicates that about 0 .2 $ benzenoid structure is present. Liquid Residue Concentration —

0.0S53 molar

The extinction coefficients of the observed max­ ima are listed below;

h

t

2980 X

0.47

2790

0.75

2592

1.68

2576

1.70

2480

1.56

About 0.3$ benzenoid structure is indicated.

Mass spectra of the parent octylbenzanthrone and of the hydrogenated fractions revealed that the three com­ ponents consisted of geometric isomers, and that no isolated double bonds were present .m Second Preparation Hydrogenation of a second 0.20 mole of octylbenz­ anthrone with a mixture of UOP nickel and Raney nickel, prepared by the Raney Catalyst Company, absorbed 0.80 mole of a theoretical 1.99 molesat 200°.

After drying

and introducing fresh catalyst, another 0.78 mole was absorbed. 200°.

Only 0.22 mole was absorbed in a third pass at

The total hydrogen absorbed was 1,85 moles of a

theoretical 2.0 moles, leaving about 9^ of the original double bonds.

This is in good agreement with ultraviolet

spectrum data which indicate that 3°jo benzenoid structure or Scjo of the double bonds remain. The partially hydrogenated material was again hydrogenated using a mixture of UOP and .V- 6 Raney nickel catalysts.

Hydrogen corresponding to 10$ of the original

double bonds was absorbed.

The total hydrogen absorbed

was 101 $ of theoretical. The catalyst was removed by filtering through silica gel, and 56 g. of the hydrocarbon was obtained by simple distillation at 192° at 0.3 mm. * The mass spectra were determined and interpreted at the Shell Oil Company, Houston, Texas.

154,

Third

Preparation

A 175 g. charge of octylbenzanthrone, in 150 ml, of decalin, was hydrogenated in the liner of bomb 1-B over 9 g, of UOP nickel and 9 g, of //-6 Raney nickel. At 300°and 1600 psi, 56% of the theoretical hydro­ gen was absorbed. The catalyst was removed by filtering through silica gel.

After removing the wash hexane, the material

was dried by distillation of about 50 ml. of decalin up to a temperature of 85° at 20 mm. The partially hydrogenated material was recharged to the liner of bomb 1-B with 9 g. of UOP and 9 g. of W-6 Raney nickel.

The bomb was rocked for two hours at 150°

and 1600 psi and four hours at 200° and 1600 psi.

Evidently

the hydrogen inlet valve leaked through to the tank and no reliable data were obtained on the hydrogen absorbed.

It

is estimated that an additional23% of the theoretical hydro­ gen was taken up. The catalyst was again removed by gel and the wash hexane distilled.

The residue was combined with the hydro­

carbon obtained from the second preparation and Claisen distilled, Fctn. 1

Still. *■ ■

B.p.

■

Press.

T.Wt.

'

" •

'

1 ’

225°

210°

0.7 mm.

2

230

216

0.5

188

3

235

218

0.5

229

”

’

94 g.

All three fractions were sligntly yellow in color.

The ultraviolet spectrum of fraction 2 indicated

the presence of a large amount of benzenoid structure in the compound. The distillate was charged to the liner of bomb 1-B with 15 g. of V/-6 Raney nickel and rocked at 200° and 2500 psi for 20 hours. at 20° was absorbed.

About 500 psi of hydrogen measured This corresponds to another 20°jo of

theoretical hydrogen necessary to saturate the original charge. On removing the material from the bomb the cat­ alyst was found to settle rapidly.

Probably the yellow

color noted in the charge was due to residual ketone, and water, formed during the hydrogenation, affected the catalyst. The catalyst was removed in the usual manner and the hydrocarbon charged to the six-foot Hy-Vacuum column for fractionation. T •i/ift.

n20D

Fctn.

Still.

Col.

B.p.

Press.

1

214°

181°

171°

0.18 mm.

6.5 g-

2-8

204

185

172

0.16

135

1.5081-90

9

224

185

173

0.16

155

1.5095

10

232

190

175

0.16

166

1.5100

11

241

196

178

0.16

178

1.5115

12

252

212

194

0.20

206

1.5150

13

300

219

192

0.20

219

1.5184

Ultraviolet spectra snowed that fraction 2 contained less than Ify benzenoid structure while fraction 12 contained a high concentration of unsaturated rings.

Fractions 2 through 13 were charged to the liner of bomb 1-B with about 10 g. of VI-6 Raney nickel and again hydrogenated at 200° and 2400 psi for 8 hours.

A total

of 90 psi of hydrogen was absorbed (measured at 20°). The catalyst was removed as usual and the hydrocarbon again charged to the Hy-Vacuum column for fractionat ion. n n2 0 D

Still

Col.

B.p.

Press.

216°

190°

178°

0.24 mm.

2-8

226

192

175

0.20

164

1.5073-88

9

247

189

177

0.20

181

1.5091

10

250

189

174

0.20

185

Fctn. 1

T.Y/t. 5 g.

—

-

Since per cent benzenoid structure increased with boiling point and refractive index in the previoiis fractionat ion, it was assumed that the phenomenon would hold in this case, and fraction 9 was assumed to have the highest percent of benzenoid structure.

Ultraviolet spectra of

both .05 and 0.1 molar solutions of fraction 9 in isooctane show molar extinction coefficients of .28 and .30 at 2820 £ and 2740 it, respectively. 0.1