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P U R D U E U NIV ER SITY
T H IS IS TO CERTIFY THAT TH E T H E S IS P R E P A R E D U N D E R MY SU P E R V IS IO N
b y _______________________
De ri v at iv e s
COM PLIES W ITH TH E U NIV ERSITY R E G U L A T IO N S O N GRA DU ATIO N T H E S E S
A N D IS A PPR O V ED BY ME A S F U L F IL L IN G T H IS PA R T O F TH E R EQ U IR EM EN TS
FO R THE DEGREE OF
Doctor of Philosophy
TO T H E LIBR A R IA N :---T H IS T H E S IS IS N O T TO B E R EG A R D E D A S C O N FIDENTIA L.
PR O V E S S O B
GRAD. SCHOOL FORM e—3-49—IM
CH A R G E
DERIVATIVES OF HEXAOHLOROCYCLOPENTADIENE A Thesis Submitted, to the Faculty of Purdue University by Henry Rakoff In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy June, 1950
ProQuest Number: 27714152
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uest ProQuest 27714152 Published by ProQuest LLC (2019). C opyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C o d e M icroform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346
ACKNOWLEDGEMENT The author is deeply grateful to Dr. E. T. McBee who was in direct charge of this investigation.
ment is made to Mr. J . Sconce and to Dr.'s H. C. Brown, 0. R. Pierce, and Z. D. Welch for helpful advice.
suggestions and criticisms, thanks are due to R. K. Meyers, to E. Rapkin, and to all the research fellows with whom the author has been associated. This investigation was financed by a grant from the Hooker Electrochemical Company administered by the Purdue Research Foundation.
TABLE OF CONTENTS Page
ABSTRACT Part 1#
The Preparation of ^-(Dichloromethylene)-l,?,4,4,5,5-hexachlorocyclopentene ...........
Part 2 . Diene Reactions of Hexachlorocyd o pent adiene with Halogenated Olefins .. Part 3#
Attempted Preparation of 5»5“Difluorotetrachlorocyclopentadiene .......... xviii
PREFACE ......................................... PART I.
THE PREPARATION AND PROOF OF STRUCTURE OF 3-(DICHLOROMETHYLENE)-l,2,4,4,5,5-HEXÀCHL0R0CYCLOPENTENE
Preparation of 3-(dichloromethylene)-!,2,4,4,5,5hexachlorocyclopentene by the reaction of hexachloropropene with hexachlorocyclopentadiene: With continuous removal of tetrachloroethylene ..........................
By repeated filtration of the solid product ..........................
In a sealed tube .......
In a sealed tube in the presence of diphenylamine ....................
At the reflux temperature at atmospheric pressure .............. «..........
préparation of 5-(dichloromethylene)-2 ,3dichloro-2-cyclopentene-l,4-dione ..........
Action of potassium hydroxide solution on 5“ (dichloromethylene)-2 ,3-dichloro-2-cyclopentene-1,4-dione ...................
Preparation of hexachlorobenzene by prolonged heating of a mixture of hexachloropropene and hexachlorocyclopentadiene .........
Reaction between hexachloropropene, hexachloro cyclopentadiene , and tetralin .....
Reaction between hexachlorocyclopentadiene and tetralin .............................
Reaction between hexachloropropene and tetralin ..
DIENE REACTIONS OF HEXACHLOROCYCLOPENTA DIENE WITH HALOGENATED OLEFINS
Preparation of 1,2,3,4,5 ,6 ,7 >7-octachlorobicyclo(2 .2 .1 .)-2 -heptene .......
Preparation of 5 >6-dibromo-1,2,3>^ >7>l ^ h e x a . ^ chlorobicyclo(2 .2 .1 .)-2-heptene .......
Preparation of 5-methyl-l,2,3,4,6,7,7-heptachlorobicyclo(2 .2 .1 .)-2-heptene ......
Preparation of 5-chloromethyl-l,2,3,4,7,7hexachlorobicyclo(2 .2 .1 .)-2-heptene ......
Preparation of 5-Ghloromethyl-l,2,3,4,6,7,7heptachlorobicyclo(2 .2 .1 .)-2-heptene ........
Attempted diene reactions of hexachlorocyclo pentadiene with: Vinylidene chloride .....................
220.127.116.11 .3-Pentachloropropene .............
ATTEMPTED PREPARATION OF 5 ,5-DIFLUOROTETRAOHLOROCYOLOPENTADIENE
FluorinatIon of hexachlorocyclopentadiene with: Antimony trifluoride at atmospheric pressure ••.
Antimony trifluoride in an autoclave ..........
Hydrogen fluoride at 0°C.
Hydrogen fluoride at SO°C*
Hydrogen fluoride and mercuric chloride .....
Potassium fluoride .........................
Antimony trifluoride and catalytic amounts of antimony pentachloride ...................
Antimony trifluoride and antimony penta chloride ..........
Hydrogen fluoride and antimony pentachloride •••
BIBLIOGRAPHY .... VITA ............... ............................
LIST OF TABLES Table 1. 2#
Page Diene Reactions of Hexachlorocyclopenta diene with Halogenated Olefins ♦•••••••••• Action of Various Fluorinating Agents on Hexachlorocyclopentadiene ...........
(Contribution from the Department of Chemistry, Purdue University and Purdue Research Foundation) THE CHEMICAL BEHAVIOR OF HEXACHLOROCYCLOPENTADIENE , III. THE PREPARATION OF 3-(DICHLOROMETHYLENE)-1,2,4,4,5,5-HEXACHLOROCYCLOPENTENE2 By Earl T. McBee and Henry Rakoff
(1) Newcomer and McBee, J. Am. Cham. Soc.. 71. 946, 952 (1949) (2) Contains material from Mr. Rakoff*a doctoral thesis. AN ABSTRACT During the course of investigations on the chemical behavior of hexachlorocyclopentadiene, it was found that the reaction of hexachloropropene with hexachlorocyclopentadiene affords a convenient and novel method for the preparation of 3-(dichloromethylene)-!,2,4,4,5,5-hexaehlorocyclopentene (I). Prins
reported the preparation of a compound C^Clg,
(3 ) Prins, J. Prakt. Chem.. (2) j$2., 422 (1914) (4) Prins, Reo. trav. chim., 65., 455 (1946) (5 ) Prins, Reo. trav. chim., 6 8 . 419 (1949 ) m.p. IS30, by the action of copper powder or copper bronze on hexachloropropene for which he suggested^ three possible
(6 ) Prins, van Brederode, Gerding, Rec. trav. chim., 6 5 . 184 (1946) --- --- --structures, I, la, or lb.
Cl Cl 2
h z :c c i 2 c i - = = _ J c i
Clg i i
No yields were reported but it appears that they were low. Carbon tetrachloride, tetrachloroethylene, 3“ (dichloromethylene)-l,2,4,4,5 -hexachlorocyclopentene (I), and a small amount of hexachlorobenzene are obtained when a mixture of hexachloropropene and hexachlorocyclopentadiene is heated at 218°. 64$ and
Yields and conversions of I as high as
respectively, based upon the hexachlorocyclo
pentadiene utilized, are obtained if the tetrachloroethylene is removed as it is formed.
If the tetrachloroethylene
is permitted to accumulate in the reaction mixture, the reflux temperature decreases, resulting in a much slower rate of reaction.
A considerable amount of hexachlorobenzene is
obtained, with a decrease in the yield of I, if the reactants are heated above 240° for several hours• The conversion of CôClg, m.p. 153°, to hexachlorobenzene at 500° has been re ported.^
(7) Krynitsky and Carhart, J. Am. Chem. Soc., 71, 816 (1949) A simple equation, (a), for the preparation of I involves the formation of an equimolar amount of tetra chloroethylene.
However, greater than equimolar amounts of
tetrachloroethylene are obtained.
The additional tetra
chloroethylene and the presence of carbon tetrachloride 3 7
may result from chlorinolysis of hexachloropropene. 9
The following proposed sequence accounts for the observed results. (a) C5 C16 (b)
--- > C6CXg _|_ 02 014
C6016 _J_ oig
---- > CC14 _J_C2 C14
that CgClg, m.p. 183°, has
structure I hasbeen obtained.
C^Cl^Og, m.p. 215°, by the action of sulfuric acid on C^Clg, m.p. I830 • Other investigators^ reported the melting point of this diketone as 226-228°.
On treatment with
aqueous potassium hydroxide, it liberated monochloroacetylene• Sulfuric acid hydrolysis of la or Ib could not yield a diketone with the empirical formula indicated.
is therefore favored. Hydrolysis of I could yield two diketones, II and Ila.
Compound lia could be formed by direct hydrolysis
while II could be formed by addition of sulfuric acid to the double bond of I, followed by elimination of hydrogen chloride and subsequent hydrolysis.
Cl Cl II
A compound which is believed to be ^-(dichloromethylene)-2,3-dichloro-2-cyelopentene-1,4-dione (II), m.p. 232°, was obtained by sulfuric acid hydrolysis of I.
hydrolysis product, on treatment with aqueous potassium hydroxide, liberated monochloroacetylene. Dichloromaleic acid was isolated from the basic solution and characterized g by its derivative with anthracene.
Diels and Thiele, Ber., %1, 1173 (193*) The following reaction sequence is proposed.
p 01 CJ1 Ç. 3 1 2 = 0 5 - 0 - 0 = 0 — COK
_ — 08 010 18 IrCOlr— 0 —0. C— 0 —OK1 I
KOH — >
0C 1 = CH +
The overall reaction has an analogy
(9) Jackson and Flint, Am. Chem. J.,
?, K 0 0 -0 Z 3 3 — 0 -0 K
in the cleavage of
2,3,5,5-tetrabromo-2-cyclopentene-l,4—dione by weakly basic reagents into dibromomaleic acid and methylene bromide.
last step is analogous to the basic cleavage^ of propynal
(10) Claisen, Ber., ]1, 1023 (189*) into acetylene and sodium formate. From this evidence, it would appear that G^Cl^Og,
m.p. 232°, has the structure II since, of the two formulas II and lia, it is the only one which could yield the observed reaction products.
Since structures la and Ib would not be
expected to yield compound II, C^Clg» m.p. 183°, must have structure I. EXPERIMENTAL Materials. Hexachlorocyclopentadiene was obtained through the courtesy of the Hooker Electrochemical Company• Hexa chloropropene was obtained from Halogen Chemicals, Inc. and from Columbia Organic Chemicals Co., Inc. 3-(Dichloromethylene)-1.2.4.^.5.5-hexachlorocyclopentene (I). Hexachloropropene (3 H
g., 1.25 mole) and hexachloro
cyclopentadiene (3^2 g., I .25 mole) were placed in the one liter two necked pot of a two foot rectifying column packed with glass helices.
Reactant temperatures were measured by
a thermometer immersed in the liquid.
The column temperature
was maintained at about l4o° throughout the entire run.
reactants were heated and the liquid temperature was 218° when boiling commenced.
Within two to three hours, tetra
chloroethylene refluxed in the column head.
As the tetrachloro
ethylene was removed, the temperature in the pot increased. To avoid the formation of excessive amounts of hexachloro benzene, heating was discontinued when the temperature of the reactants reached 240°. distilled.
During the run, 206 g. of liquid
The reaction mixture was cooled and filtered and
the precipitate was washed with ice cold petroleum ether. The solid (230 g.), which was pink in color, was recrystallized
from petroleum ether (90 -100°) to give 3-(dichloromethylene)1 .2 .18.104.22.168 -hexachlorocyclopentene> m.p. 183°•
Analysis: Calc*d.for C^Olg: Found:
Cl, 79*7%; G, 20.2^ Cl, 30.6#; C, 20.38#, 20.$0#
The material which distilled through the column was rectified to yield 1 5 «5 g* (0 .1 mole) of carbon tetra chloride and 164.5 g. (0.93 mole) of tetrachloroethylene. From the liquid pot residue, 11.5 g. (0.046 mole) of hexa chloropropene and 67 g • (0.245 mole) of hexachlorocyclopenta diene were recovered.
The conversion to 3-(dichloromethylene)-
1 .2 .4.4.5 .5 -hexachlorocyclopentene was 51 # while the yield,
based upon hexachlorocyclopentadiene utilized, was 64#. R-(Dichloromethylene)-2.3-dichloro-2-cvclopentene-l«4-dione (II). A mixture of I (40 g., 0.11 mole) and concentrated sulfuric acid (250 ml.), in a one liter three-necked flask, was heated on a chloride was
steam bath, with stirring, for two hours. evolved.
As the solution cooled
perature, a yellow solid precipitated.
The cooled mixture
was poured onto ice and the solid which was obtained by fil tration was recrystallized from petroleum ether (90 -100 °) to yield 13 g* (47# conversion) of 5-(&ichloromethylene)-2,3dichloro-2-cyclopentene-l,4-dione, shiny white plates, m.p. 2 32°.
In one experiment, which could not be duplicated, a conversion to II of 67# was realized. Analysis: Calc'd. for C^Cl^Og:
57*3#; 0, 29*0#, 29 .3#
Action of Potassium Hydroxide Solution on 5-(dichloromethylene)-2,3-dichloro-2-cyclonentene-l.^-dione (II). Three grams of II was added, slowly and cautiously, to a solution of 5 §>• of potassium hydroxide in 50 ml* of water• Small flames were observed and a black soot formed due to the explosions of the liberated monochloroacetylene After the reaction had ceased, the liquid was filtered, acidified, and extracted with ether for sixteen hours♦ On evaporation of the ether, a red oil remained which crystallized on boiling with petroleum ether (30-60°)*
The crude material
was sublimed under reduced pressure to yield a white solid, m.p. 119-120 °, the melting point of dichloromaleic acid (or its anhydride) . 11
(11) Zincke, Fuchs, Ann.. 267. 20 (1892) The product melting at 119-120° was treated with anthracene according to the method of Diels and Thiele.
Petroleum ether (90-100°) was employed as the recrystalliza tion solvent rather than the recommended mixture of acetic anhydride and acetonitrile.
The white solid obtained melted
at 233“23^0, the reported melting point of anthracene-9 ,10 endodichloromaleic anhydride. Acknowledgement: The authors express their indebtedness to the Hooker Electrochemical Company for defraying the expenses of this investigation. are greatly appreciated.
The helpful suggestions of Mr. J. Sconce
A new synthetic method for the preparation of 3”(di
chloromethylene )-l,2 ,4,4,3 ,3-hexachlorocyclopentene based on the reaction of hexachloropropene with hexachlorocyclo pentadiene is described* 2*
Sulfuric acid hydrolysis of 3"(dichloromethylene)-!,2,
4,4,5 ,5 -hexachlorocyclopentene yields 5 -(dichloromethylene)2 ,3~dichloro-2-cydopentene~l,4-dione, m.p. 232°. 3.
Chemical evidence for the assignment of structures is
presented. 5 ~(Dichloromethylene)-2 ,3-dichloro-2-cyclopentene1 ,4-dione is cleaved by aqueous potassium hydroxide to yield
dichloromaleic acid and monochloroacetylene.
(Contribution from the Department of Chemistry, Purdue University and Purdue Research Foundation) DIENE REACTIONS OF HEXACHLOROCYCLOPENTADIENE WITH HALOGENATED OLEFINS
By Earl T. McBee and Henry Rakoff
(1) Contains material from Mr. Rakoff's doctoral thesis.
AN ABSTRACT Coffman and Carothers
studied the Diels-Alder
(2) Coffman and Carothers, J. Am* Chem. Soc.. 99. P04o (1933) reaction with halogenated dienes and found that dienes of the structure CIC-C-C-C or C=C(Cl)C(Cl)-C do not add dienophiles# Nevertheless, Prill^ was able to effect the diene synthesis
(3) Prill, J. Am. Chem. Soc.. 6%, 62 (194?) between hexachlorocyclopentadiene and such dienophiles as maleic anhydride and acrylonitrile. In addition, 1,2,3>4tetrachloro-5 ,5“ûialkoxycyclopentadiene^ and 1,2,3,4-tetra-
(4) Newcomer and McBee, J. Am. Chem. Soc♦. 71. 9^6 (1949) chlorocyclopentadiene^ have been observed to undergo this
(5) Meyers, Ph.D. Thesis, Purdue University, 1930
The diene synthesis with hexachlorocyclopenta
diene has now been extended to include reactions with halo genated olefins.
The adducts obtained are listed in Table 1.
Halogenated olefins will undergo the diene synthesis if vigorous conditions are employed.
The reactions between
hexachlorocyclopentadiene and halogenated olefins were con ducted, in most instances, in sealed tubes at about 200°• Of the nineteen olefins studied, only five yielded adducts. Those olefins which do undergo the diene synthesis all possess one feature which is lacking in the olefins which do not undergo the reaction.
These former olefins, 1,2-di-
chloroethylene, 1 ,2-dibromoethylene, 1-chloropropene, 3“ chloropropene, and 1 ,3-dichloropropene all have at least one hydrogen atom on each doubly bonded carbon atom.
olefins which do not react have, at most, a hydrogen atom on only one doubly bonded carbon atom. The non-reactivity of fourteen of the olefins studied may be due to steric considerations.
reaction is believed to involve, first, a polarization of the double bonds.^
The reaction is then postulated to be
(6 ) Bergmann, Eschinazi, and Neeman, J . Org. Chem., (19Ï3)
initiated by an ionic reaction involving electron transfer from the diene to the dienophile.
This step results in a
complex that is held together by ionic forces.
ically, this complex may be visualized as two charged parallel
xi Table 1 DIENE REACTIONS OF HEXACHLOROPENTADIENE WITH HALOGENATED OLEFINS
m.p. 170 -190°
m.p. 210 °
m.p. 197 -198°
surfaces, oriented in such a manner as to take maximum 7
advantage of electrostatic attractive forces•'
(7) Woodward, J.. Chem. Soc.. 64, J0 5 S (1942) step is then a rearrangement of the ionic complex to the stabilized adduct. For a reaction to take place between two charged surfaces, it must be possible for the two surfaces to come within close proximity of each other.
It is believed, in
the case of the fourteen olefins which do not react, that this requirement cannot be fulfilled.
A consideration of
the Van der Waals radii of the various atoms lends credence g
to this suggestion.
The pertinent Van der Waals radii are:
(g) Pauling, The Nature of the Chemical Bond* p. 189, Cornell University Press, Ithaca, New York, 19^8 CH-j
I .35 Î .
1,2-Dichloroethylene reacts with hexachlorocyclo pentadiene probably because this molecule can, in its cis form, approach sufficiently close to the hexachlorocyclo pentadiene molecule for the electrostatic effect to become operative.
The fact that trans 1,2-dichloroethylene will
also undergo this reaction may be accounted for by the obser vation that trans 1 ,2-dichloroethylene isomerizes to the cis isomer under the influence of heat.
(9) Olson and Maroney, J. Am. Chem. Soc,., 56* 1320 (193^)
trichloroethylene, and tetrachloroethylene, on the other hand, are prevented from approaching close to the hexa chlorocyclopentadiene molecule by the bulky chlorine atoms» When heated with hexachlorocyclopentadiene at 200°, they do not yield adducts. The Van der Waals radius of the fluorine atom is only a little larger than that of the hydrogen atom and it might be possible for the tetrafluoroethylene molecule to approach sufficiently close to the hexachlorocyclopentadiene molecule to react with it.
However, under the experimental
conditions employed, tetrafluoroethylene dimerizes to form 10 octafluorocyclobutane. Since asym-dichlorodifluoroethylene
(10) Coffman et al., J. Am. Chem. Soc., 71. 490 (1949) which, according to this proposal, would not be expected to react with hexachlorocyclopentadiene also dimerizes^1, little
(11) Henne and Ruh, J. Am. Chem. Soc.. 69. 279 (1947) can be said of the effect of the size of the fluorine atom. In the chloropropenes, the methyl group as well as the chlorine atom could prevent close approach of the diene and dienophile.
Thus, attempted reactions between
hexachlorocyclopentadiene as the diene and 1 ,1-dichloropropene, 1 ,2-dichloropropene, 2 ,3-diehloropropene, 1 ,1 ,2-trichloro-
propene, 1 ,2 ,3 ,3-tetrachloropropene, 1 ,1 ,2 ,3 ,3-pentachloropropene, l,l,2-trichloro~3 ,3 ,3~trifluoropropene, y.,2 ,3-
tetrachloro-3 ,3-clifluoropropene, or hexafluoro-2 ,3”diohloro2 -butene as the dienophile did not yield adducts.
chloropropenes which did react have a hydrogen atom on each doubly bonded carbon atom. EXPERIMENTAL 1 .2 .3 ,
5 .6 ,7 ,7-0 ct achlorobicyclo(2 .2 .1 .)-2-heptene.
Hexachlorocyclopentadiene (54 g., 0.2 mole) and cis, 1 ,2-dichloroethylene (20 g., 0 .2 mole) were heated in a
sealed tube at 200° for twenty-five hours.
The tube was
opened after it had been cooled in a dry ice-trichloroethylene bath and the brown solidwhich it contained was purified by recrystallization from methanol to yield 28 g. (38 ^ conversion) of a mixture of isomers of 1,2,3,4,5,6 ,7 ,7-octachlorobicyclo(2 .2 .1 .)—2—heptene, m.p. 170 —190 ^# When trans 1,2-dichloroethylene was substituted for the cis isomer, only 20 g. (26% conversion) of crude product was obtained. Analysis:
0, 22.7%; H,
Found: C, 2 3 .0%; H, 0.49% 9.6-Dibromo-l.2,22.214.171.124-hexachlorobicyclo(2.2.1.)-2-heptene. Hexachlorocyclopentadiene (54 g., 0.2 mole) and 1,2dibromoethylene (37 g*, 0 .2 mole) were heated in a sealed tube at 200° for twenty-seven hours.
A solid precipitated
when the tube was cooled in a dry ice-trichloroethylene bath.
The dark colored solid (20 g.) was dissolved in meth
anol and the solution was boiled with Norite and filtered. After three recrystallizations from methanol, 15 g. (16%
conversion) of 5,6-dibromo-l,2,3,4,7 ,7-hcxachloroMcyclo(2 .2 .1 .)-2-heptene was obtained as white crystals melting at 210 °. Analysis: Calc’d. for CyHgBrgCl^ Total halogen (as chloride);
5 -Methyl-l.2 .3 .4 .6 .7 ,7-heptachlorobicyclo(2 .2 .1 .)-2-heotene.
Hexachlorocyclopentadiene (68 g., 0.25 mole) and freshly distilled 1-chloropropene (19 g*, 0.25 mole) were heated in a sealed tube at I5 O-I6O0 for twenty-four hours# The cooled tube was opened and its contents (£& g.) were distilled.
Seven grams of 1-chloropropene (b.p. 35°/7^5 mm.
Eg), 5 S g. of hexachlorocyclopentadiene (b.p. E>3°/3 mm. Hg), and 33 g* of a black residue, which solidified on cooling, were obtained.
The black mass was dissolved in methanol and
the solution was boiled with Norite and filtered.
in a dry ice-trichloroethylene bath, the solution deposited 6 .5 g* of brown crystals, m.p. 165-130°•
A pure sample of the
product, 5 -methyl-l,2 ,3 ,^,6 ,7 ,7~^optachlorobicyclo(2 .2 .1 .)2-heptene melted at 197-193°•
The conversion was 7*5$ while
the yield, based upon hexachlorocyclopentadiene utilized, was 14.5% When the reactants were heated at 100°, no reaction took place. sulted.
At 200°, however, extensive decomposition re
The optimum temperature for this reaction probably
lies somewhere between 100° and 150 °.
Analysis: Calc ,cU for
OgH^Oly: 0, 2 Found:
C, 23.2^; H, 1.3^
5-Ghloromethyl-l.2.3.^.7.7-hexachlorobicyclo(2.2.1.)-2-heptene• Hexachlorooyclopentadiene (5^ g * , 0,2 mole) and 3chloropropene (15 g», 0 .2 mole) were heated in a sealed tube at 200° for twenty-five hours.
took place and considerable pressure was released when the tube was opened.
The contents of
the tube were steam distilled
and the yellow-brown oil which was obtained was dried and rectified to give 18 g. (27% conversion) of 5 -ohloromethyll,2 ,3 ,^,7 ,7-h8X&chlorobicyclo(2 .2 .1 .)-2-heptene, b.p. 14-0l430/4 mm. Hg. A 68% conversion to the bicyclic compound can be realized by conducting the experiment at 125 °
(12) Meyers, Ph.D. Thesis, Purdue University, 1950 5 -Chloromethyl-l.2.1.4,6 .7 .7-heptachlorobicyclo(2 .2 .1 .)-2-
heptene. Hexachlorooyclopentadiene (273 g*, 1 mole) and 1 ,3-dichloropropene (111 g., 1 mole) were heated, in a one
liter flask equipped with a reflux condenser, at 130° for twenty-four hours.
Distillation of the reaction mixture
yielded 73 g* of 1 ,3-dichloropropene (b.p. 106-113 °/7^2 mm. Hg) and 205 g* of hexachlorooyclopentadiene (b.p. 9 S-IO70/ 7 mm. Hg).
Eighty-six grams of a black liquid remained in
The black liquid deposited brown crystals during
storage for four weeks at room temperature.
crystals were dissolved in methanol and the solution was boiled with Norite and filtered.
The clear solution, in
a beaker, was cooled in a dry ice-trichloroethylene bath. The inside wall of the beaker was scratched with a glass rod as the solution warmed up to room temperature.
precipitate which was obtained was filtered to give 55 g* of a yellow-brown solid, m.p. 55-65°•
A pure sample of the
product, 5 -ohloromethyl-l,2 ,3 ,^,6 ,7 ,7-hept&chlorobicyclo(2.2.1.)-2-heptene was white and melted at 7&-80°.
version was 15% while the yield, based upon 1 ,3-dichloro propene reacted, was 43%. Analysis: Oalc'd. for O^H^Cl^: Found:
C, 25*0%; H, 1.04% C, 2 5 .5%; H, 1.07%
Acknowledgement : The authors express their indebtedness to the Hooker Electrochemical Company for defraying the expenses of this investigation. SUMMARY The diene reaction of hexachlorooyclopentadiene with a
series of halogenated olefins
has been studied.The
preparation of five new Diels-Alder adducts, together with possible reasons for the non-reactivity of the other olefins studied, is presented.
(Contribution from the Department of Chemistry, Purdue University and Purdue Research Foundation) ATTEMPTED PREPARATION OF 5,5-DIFLUOROTETRACHLOROOYOLOPENTADIENE By Earl T. McBee and Henry Rakoff
(1) Contains material from Mr. Rakoff1s doctoral thesis. AN ABSTRACT During the course of investigations on the chemical behavior of hexachlorooyclopentadiene, it was decided to attempt to prepare 5 ,5-&ifluo?otetr&chlorocyclopentadiene in order to compare its chemical behavior with that of hexachloro cyclopentadiene.
Several methods for the introduction of a
fluorine atom into a molecule were investigated but in no case was the desired product obtained.
The results obtained
are summarized in Table 1. Dichlorohexafluorocyclopentene (b.o. 89°) has been obtained
by the action of antimony pentafluoride on hexa-
McBee. Wiseman, and Bachman. Ind. Eng. Chem., '59. 415 (1947)
The preparation of dichlorohexafluoro
cyclopentene (b.p. 89°) and of pentafluorotrichlorocyclopentene (b.p. 121°) are mentioned in a patent.^
(3) Kischitz, Goochenoor, and Brailsford, U.S. 2,449,233 Sept. 14, 1948 (4) Newcomer, Unpublished observations.
Table 1 ACTION OF VARIOUS FLUORINATING AGENTS ON HEXACHLOROOYCLOPENTADIENE
Products b#p« g
170 °, 5 .5 hrs. in flask
200 20 hrs. in autoclave
SbF^ + SbCl5
170 °-200 o
175 ° and 200 °
HF 4 SbClc
* Higher boiling products also obtained ** X means product obtained.
prepared a tetrachlorotetrafluorocyclopentene (b.p. 151 °) by the action of a mixture of antimony trifluoride and an timony pentachloride on hexachlorooyclopentadiene• Hexachlorooyclopentadiene does not react with hydrogen fluoride either at 0° or at 50°.
(hydrogen fluoride and mercuric chloride) and potassium fluoride are also ineffective as fluorinating agents.
antimony trifluoride in an autoclave or with a mixture of antimony trifluoride and antimony pentachloride, addition and substitution occur to form dichlorohexafluorocyclopentene, pentafluorotrichlorocyclopentene, and tetrachlorotetrafluoro cyclopentene • A mixture of hydrogen fluoride and antimony penta chloride gives, in addition to these three products, two fractions boiling at higher temperature• One (b.p. 106107°/5g-59 mm. Hg) was first thought to be a difluorotetrachlorocyclopent&diene• Analytical results, however, were inconclusive• The compound resisted oxidation with potassium permanganate and would not react with maleic anhydride in the diene synthesis. The second fraction (b.p. 75~77*5°/3 mm* Hg) has a boiling point close to that predicted for a monofluoropentachlorocyclopentadiene• Analytical results were inconclusive and the product would not react with maleic anhydride in the diene synthesis. The pentahalocyclopentadienyl ion is unique in
that all positions on the ring are equivalent• Thus it is possible that not one, but three isomeric difluorotetrachlorocyclopentadienes would be formed as indicated in the following scheme♦
F f ^ ^ N ci
F f/ Z^ s >Cl 2-S*4-°G. solidified in the trap.
A white solid (14 g.), This white solid has
the same melting point as the dimer of dichlorodifluoro ethylene (l4).
Unreacted hexachlorocyclopentadiene was also
recovered. Hexachlorocyclopentadiene and 1.1-dichloropropene.
Hexachlorocyclopentadiene (5% g*, 0.2 mole) and 1,1dichloropropene (22 g., 0 .2 mole) were heated in a sealed
33 tube at 200°C# for twenty-six hours. the tube was opened.
A gas escaped when
Unreacted 1,1-dichloropropene was
recovered by distillation of the reaction mixture at atmos pheric pressure while unreacted hexachlorocyclopentadiene was obtained by distillation at 3 mm* Hg pressure. Hexachlorocyclopentadiene and 1 .2-dichloropropene♦ Hexachlorocyclopentadiene (68 g., 0.25 mole) and 1 .2-dichloropropene (28 g., 0.2 5 mole) were heated in a 100 ml. flask at the reflux temperature for twenty-two hours.
The liquid turned golden orange very rapidly.
distillation at atmospheric pressure yielded unreacted 1 ,2dichloropropene while unreacted hexachlorocyclopentadiene was recovered by distillation of the reaction mixture at reduced pressure. Hexachlorocyclopentadiene and 2.3-dichloropropene. Hexachlorocyclopentadiene (80 g., 0.29 mole) and 2 .3-dichloropropene (28 g., 0 .2 5 mole) were heated in a 200 ml.
round bottomed flask at 115°C. for twenty-four hours. Dis tillation of the dark colored liquid gave 2.5 g* of 2 ,3dichloropropene (b.p. 92°0./7^5 mm. Hg) and 65 g. of hexa chlorocyclopentadiene (b.p. 90°0./4 mm. Hg).
grams of a viscous, black liquid, probably an autoconden sation product of 2 ,3-dichloropropene, remained in the re action vessel. Hexachlorocyclopentadiene and 1,1,2-trichloropropene♦ Hexachlorocyclopentadiene (68 g., O .25 mole) and
1 .1 .2-trichloropropene (36 g#, 0 .2^ mole) were heated in a 200 ml. round bottomed flask at the reflux temperature for
Distillation of the reaction mixture
yielded 32 g. of 1 ,1 ,2-t richloropropene (b.p. ll6-1320 C./71$-5 mm. Hg) and 64 g. of hexachlorocyclopentadiene (b.p. 95” 103°C./5-6 mm. Hg). Hexachlorocyclopentadiene and 126.96.36.199-tetrachloropropene (12). Hexachlorocyclopentadiene (68 g., 0.25 mole) and 1 .2 .3 .3-tetrachloropropene (45 g., 0 .2 5 mole) were heated in
a 200 ml. round bottomed flask at 190°C. for forty-four hours. No reaction took place.
Toluene (50 ml.) and a few crystals
of trichloroacetic acid were added.
Heating was then con
tinued (b.p. 13&°C.) for eighty-four hours.
the reaction mixture at reduced pressure yielded only un reacted starting materials. Hexachlorocyclopentadiene and 1.1.2,3,3-pentachloropropene (33.35). Hexachlorocyclopentadiene (69 g., O .25 mole) and 1 .1 .2 .3 .3-pentachloropropene (55 g*, O .25 mole) were heated
at 205°C. for twenty-four hours.
Distillation of the reaction
mixture under reduced pressure yielded only unreacted starting materials. Hexachlorocyclopentadiene and l.l,2-trichloro-3.3.3-trifluoropropene. Hexachlorocyclopentadiene (54 g., 0.2 mole) and 1.1.2-trichloro-3 ,3 ,3-trifluoropropene (40 g., 0 .2 mole) were heated in a sealed tube at 200°0. for twenty-six hours.
35 unreacted starting materials were obtained by distillation of the tube contents• Hexachlorocyclopentadiene and 188.8.131.52-tetrachloro-3,3-difluoropropene# Hexachlorocyclopentadiene (54 g*, 0.2 mole) and l,l,2 ,3-tetrachloro-3 >3~33) that hexachlorocyclopentadiene will undergo reactions character istic of a conjugated diene system as well as those charac teristic of a compound containing allylic halogen atoms » It was considered desirable to attempt the preparation of 5>5“ difluorotetrachlorocyclopentadiene to compare its chemical behavior with that of hexachlorocyclopentadiene• Several methods for the introduction of a fluorine atom into a molecule were investigated, but in no case was the desired difluorinated product obtained.
The results obtained are
summarized in Table 2. Dichlorohexafluorocyclopentene (b.p. 39°C.) has been obtained (24) by the action of antimony pentafluoride on hexachlorocyclopentadiene.
The preparation of dichloro
hexafluorocyclopentene (b.p. 89°0*) and of pentafluorotrichlorocyclopentene (b.p. 121°C.) are mentioned in a patent (19)•
Newcomer (26 ) has prepared a tetrachlorotetrafluoro-
cyclopentene (b.p. 151 °0 .) by the action of a mixture of antimony trifluoride and antimony pentachloride on hexachloro cyclopentadiene . Since it was desired to replace only the two allylic chlorine atoms of hexachlorocyclopentadiene, antimony tri fluoride, was tried first (1 5 ).
At atmospheric pressure,
antimony trifluoride did not fluorinate hexachlorocyclopenta diene.
When hexachlorocyclopentadiene and antimony trifluoride
Table 2 ACTION OF VARIOUS FLÜORINATING AGENTS ON HEXACHLOROCYCLOPENTADIENE
b9-difluorofluorene by the action of hydrogen fluoride on 9,9-dichlorofluorene in the presence of mercuric chloride.
Since the chlorine
atoms on the 9-position of fluorene are in a position analogous to that of the allylic chlorine atoms of hexachlorocyclopenta diene, it was decided to investigate the action of mercuric fluoride.
Realizing that it was possible that hydrogen
fluoride might add to the double bonds of hexachlorocyclo pentadiene, the action of hydrogen fluoride on hexachlorocyclo-
pentadiene was investigated first. It was found that hexa chlorocyclopentadiene did not react with hydrogen fluoride either at 0°0e or at £>0°Ce
The reaction between hexachloro
cyclopentadiene and mercuric fluoride (hydrogen fluoride and mercuric chloride) was then investigated.
Under the conditions
employed, no fluorination took place. Wiseman (24) used the reaction of antimony penta chloride and hydrogen fluoride with hexachlorocyclopentadiene to prepare dichlorohexafluorocyclopentene, b.p. S9°0»
this reaction, higher boiling materials are also obtained. In addition to pentafluorotrichlorocyclopentene (b.p. 121°0.) and tetrachlorotetrafluorocyclopentene (b.p. 80-Sl°0./é768 mm. Hg), there were obtained, in this investigation, a
fraction A (b.p. 106-107°C./58-59 mm* Hg) and a fraction B (b.p. 75-77•5°0./3 mm. Hg). The boiling point of fraction A, when corrected to atmospheric pressure, is within the range predicted for the boiling point of a difluorotetrachlorocyclopentadiene (ca. 190°C.)• Attempts to establish the identity of this product were unsuccessful. sistent.
Analytical results were incon
The product resisted oxidation with potassium per
manganate and would not react with maleic anhydride in the diene synthesis. Fraction B, whose boiling point when corrected to atmospheric pressure falls within the range predicted for the boiling point of a monofluoropentachlorocyclopentadiene, like wise gave inconclusive analytical results and would not react
with maleic anhydride in the diene synthesis# If fraction A is a difluorotetrachlorocyclopentadiene, it is not necessarily the desired isomer, 5 ,5-difluorotetrachlorocyclopentadiene. The pentahalocyclopentadienyl ion is unique in that all positions on the ring are equivalent#
Thus, after one of the allylic chlorine atoms
has been substituted by fluorine, a second fluorine atom can become attached to a different carbon atom.
If we assume the
reaction to proceed by an ionic mechanism, the following sequence may take place:
01 01 F
In any event, the difluorotetrachlorocyclopentadiene, if it is an intermediate in the fluorination, is probably more easily fluorinated than is hexachlorocyclopentadiene and is fluorinated further as soon as it forms* Experimental Fluorination of hexachlorocyclopentadiene with: Antimony trifluoride at atmospheric pressure* Hexachlorocyclopentadiene (546 g., 2 moles) and antimony trifluoride (720 g*, 4 moles) were placed in a two liter, three necked flask equipped with a stirrer, an air condenser protected from atmospheric moisture by a calcium chloride drying tube, and a thermometer enclosed in a glass sleeve*
The contents of the flask were heated, with stirring,
in an oil bath at about 170 °0 . for five and one half hours* The reaction mixture, when cool, was decanted and washed six times with concentrated hydrochloric acid*
The dark brown
liquid was steam distilled to yield a yellow oil which was dried and rectified and found to consist of unreacted hexa chlorocyclopentadiene * Antimony trifluoride in an autoclave* Hexachlorocyclopentadiene (273 S*, 1 mole) and antimony trifluoride (35 ^ g*, 2 moles) were heated, with shaking, in a one liter iron autoclave at 200 °0 * for twenty hours*
The valve was opened and a gas, presumably hydrogen
chloride, was bled out*
The cooled autoclave was opened and
the viscous red oil (82 g.) remaining was steam distilled to yield a yellow oil (46*5 g*) which was dried and rectified*
The following fractions were obtained from 4^ g. of liquid* Fraction
Boiling Point °0. at 745 mm. Hr .
up to 89
Small amounts of higher boiling materials were also obtained* Hydrogen fluoride at 0o0* Hydrogen fluoride (506 g.) was introduced into a dry copper pot equipped with an inlet and an outlet tube, a thermocouple sleeve and a nickel stirrer♦ The copper pot was cooled in an ice bath and with stirring, hexachlorocyclo pentadiene (100 g.) was dropped in over a period of thirty minutes*
The mixture was stirred for an additional hour at
0-2°C. and then the hydrogen fluoride was dis tilled out by heating the flask with a heat lamp*
The contents of the
reactor were poured onto ice and the organic layer was separ ated, washed several times with sodium bicarbonate solution, and dried*
Rectification of the oil at reduced pressure
yielded only hexachlorocyclopentadiene♦ Hydrogen fluoride at S0o0* Hexachlorocyclopentadiene (273 g*, 1 mole) was placed in a one liter nickel-lined autoclave.
fluoride (5 0 -60 g.) was distilled into the autoclave which
was then heated, with rocking, at 6>0°0. for seven hours.
cooled autoclave was opened and the hydrogen fluoride was bled out into a scrubber containing sodium hydroxide solution.
contents of the autoclave were poured onto ice and the oil which separated was washed with sodium bicarbonate solution until neutral.
Rectification of the dried oil at reduced
pressure yielded only hexachlorocyclopentadiene. Hydrogen fluoride and mercuric chloride. Mercuric chloride (136 g., 0 .5 mole), hexachloro cyclopentadiene (137 g« f 0 .5 mole), and chlorobenzene (25O ml.) were placed in a dry copper pot equipped with an inlet tube, an outlet tube, a thermocouple sleeve, and a nickel stirrer. The temperature in the pot was maintained between SO0 and 82°C. by means of a water bath, and hydrogen fluoride was permitted to bubble slowly through the pot contents for three hours.
The pot was then cooled and its contents were
poured onto ice.
The oily organic layer was separated, fil
tered to remove solid material, and washed several times with sodium bicarbonate solution.
The dried oil, on rectification,
gave only chlorobenzene and hexachlorocyclopentadiene• Potassium fluoride. Hexachlorocyclopentadiene (273 g., 1 mole) and powdered, anhydrous potassium fluoride (214 g., 3 .7 moles) were placed in a dry one liter three necked flask equipped with a stirrer, a thermometer, and an air condenser topped by a calcium chloride drying tube.
Ethylene glycol monobutyl
ether was added to increase the fluidity of the mixture.
The mixture was heated,
with stirring, at about
four hours♦ The cooled
reactants were filtered
tered glass disc and the solids were washed with hot portions of the reaction solvent• The filtrate was steam distilled to give a yellow oil which was dried and rectified.
fluorinated products were obtained. The reaction was repeated at about 200°0. with diethylene glycol as solvent with similar negative results. Antimony trifluoride and catalytic amounts of antimony pentachloride. A typical run is described: Hexachlorocyclopentadiene (365 g., 1.34 mole) and antimony trifluoride (960 g., 5 *36 mole) were placed in a two liter, three necked
flask equipped with a stirrer, a
dropping funnel, and a goose-neck tube
condenser set downward for distillation.
to an air
The mixture was
heated with stirring to 210°0. and antimony pentachloride was added to the flask in small portions.
experienced due to the tendency of the antimony salts to sublime and clog the condenser. The distillate was washed with concentrated hydrochloric acid to remove the antimony salts.
It was then washed with water and dried.
of the products was effected by rectification at atmospheric pressure.
Unreacted hexachlorocyclopentadiene was recovered
by rectification at 3 mm. Hg pressure. In addition to hexachlorocyclopentadiene, the following products were obtained:
Mole % Antimony pentachloride 10
Products obtained C-C1-.F. b.p. 120°C. 0
CLCl^F^, b.p. 150°C. 2 .5
OcO1^ , b.p. 150°C.
Antimony trifluoride and antimony pentachloride* Antimony trifluoride (1200 g., 6*7 moles), antimony pentachloride (466 g., 1*55 moles), and hexachlorocyclopenta diene (546 g., 2 moles) were placed in a three liter, three necked flask equipped with a stirrer and attached to a con denser set for distillation.
The mixture was heated with
stirring, and product started to distil at about 170°C. major portion of it distilled between 200° and 220°C.
difficulty was encountered due to the tendency of the antimony salts to sublime and clog the outlet tube.
was washed three times with concentrated hydrochloric acid and three times with distilled water. The oil was dried and rectified at atmospheric pressure to give dichlorohexafluorocyclopentene (b.p. S9°C.), pentafluorotrichlorocyclopentene (b.p. 121°C•) and tetrachlorotetrafluorocyclopentene (b.p. 150°C.) in addition to unreacted hexachlorocyclopentadiene• Hydrogen fluoride and antimony pentachloride. Antimony pentachloride (1362 g.) was placed in a one gallon nickel reactor equipped with a stirrer, a gas in let tube, a thermocouple sleeve, a liquid inlet tube, and a one inch pipe which served as an air cooled condenser.
parts of the reactor which came into contact with the reactants were made of nickel.
The gases issuing from the condenser
were vented to a hood through copper tubes.
The pot temperature
was maintained between 80° and 100°Ce and a total of six pounds of hydrogen fluoride was permitted to bubble through the material in the reactor.
The system was then flushed with
nitrogen to remove any excess hydrogen fluoride and hexachloro cyclopentadiene (S15 g.) was added to the reactor over a period of seventy-five minutes.
The mixture was stirred at
90°C. for an additional two and one-quarter hours. The reactor was cooled and its contents were washed ten times with concentrated hydrochloric acid, steam distilled and dried.
Rectification of the product (^#4 g.) through a
four-foot column packed with glass helices yielded the follow ing fractions:
Boiling Point, °C.
up to £9
No unreacted hexachlorocyclopentadiene was recovered* ♦Fractions obtained by rectification of fractions 10 and 11 through an eighteen inch Lecky-Ewell column*
was prepared by the reaction of hexachloropropene with hexa chlorocyclopentadiene*
This compound, on hydrolysis with
sulfuric acid, yielded 5 -(dichloromethylene)-2 ,3-dichloro-2cyclopentene-1,4-dione, m.p. 232°0*
Chemical evidence for the
assignment of structures is presented*
2 ,3-dichloro-2-cyclopentene-1 ,4-dione was cleaved by aqueous
potassium hydroxide to yield monochloroacetylene and dichloromaleic acid* 2*
The diene reaction of hexachlorocyclopentadiene with a
series of halogenated olefins has been studied*
of five new Diels-Alder adducts, together with possible reasons for the non-reactivity of the other olefins studied, is pre sented* 3*
The action of several fluorinating agents on hexachloro
cyclopentadiene was studied with the purpose of preparing 3,5-difluorotetrachlorocyclopentadiene• Hydrogen fluoride, mercuric fluoride, and potassium fluoride were found not to fluorinate hexachlorocyclopentadiene under the conditions em ployed*
Antimony trifluoride in an autoclave or a mixture
of antimony trifluoride and antimony pentachloride gave dichlorohexafluorocyclopentene, pentafluorotrichlorocyclopentene, and tetrachlorotetrafluorocyclopentene• The reaction of hydrogen fluoride and antimony pentachloride with hexachlorocyclopenta diene gave, in addition to these three chlorofluorocyclopentenes, two higher boiling products which were not identified*
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Henry Rakoff was born in Brooklyn, New York on November 1 3 , 1924.
After receiving the degree of Bachelor
of Science from the College of the City of New York in June, 1944, he entered the U. S. Navy.
Following his discharge
from service, Mr. Rakoff enrolled in the Graduate School at Purdue University and was awarded the M.S. degree in February, 1948 and the Ph.D. degree in June, 1950• Mr. Rakoff is a member of Phi Lambda Upsilon and of the Society of the Sigma Xi•