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Handbook of Antioxidants: Bond Dissociation Energies, Rate Constants, Activation Energies, and Enthalpies of Reactions [1 ed.]
 9781315893273, 9781351072373, 9781351089272, 9781351097727, 9781351080828

Table of contents :

1. Kinetics and Mechanism of Inhibited Oxidation of Hydrocarbons 2. Rate Constants of Elementary Steps of Chain Oxidation of Hydrocarbons 3. Bond Dissociation Energies and Rate Constants of Reaction of Phenols 4. Bond Dissociation Energies and Rate Constants of Reactions of Aromatic Amines 5. Dissociation Energies and rate Constants of Reactions of Hydroxylamines and Nitroxyl Radicals 6. Bond Dissociation Energies and Rate Constants of Reactions of Thiophenols 7. Phosphorus and Sulfur Containing Antioxidants Decomposing Hydroperoxides

Citation preview

HANDBOOK OF ANTIOXIDANTS Bond Dissociation Energies, Rate Constants, Activation Energies and Enthalpies of Reactions

Evguenii Denisov

Boca Raton London New York

C R C Press

CRC Press is an imprint of the

Boca Raton Tokyo Taylor &New FrancisYork Group, anLondon informa business

First published 1995 by CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 Reissued 2018 by CRC Press © 1995 by CRC Press, Inc. CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright. com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a notfor-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging-in-Publication Data Denisov, E.T.  (Evguenii Timofeevich) Handbook of antioxidants : bond dissociation energies, rate   constants, activation energies, and enthalpies of reactions / Evguenii T. Denisov. p.  cm.   Includes bibliographical references and index.   ISBN 0-8493-9426-0 (alk. paper)   1.  Antioxidants—Handbooks, manuals, etc. I. Title. QD281.O9D45 1995 547’ .23—dc20 

95-21651

A Library of Congress record exists under LC control number: 95021651 Publisher’s Note The publisher has gone to great lengths to ensure the quality of this reprint but points out that some imperfections in the original copies may be apparent. Disclaimer The publisher has made every effort to trace copyright holders and welcomes correspondence from those they have been unable to contact. ISBN 13: 978-1-315-89327-3 (hbk) ISBN 13: 978-1-351-07237-3 (ebk) Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

/ dedicate this handbook to the memory of Viktor Kondratev, who inspired me to work in the field of quantitative kinetic information.

PREFACE The objective of this Handbook is to provide scientific workers and engineers working in the field of physical chemistry of antioxidants with the comprehensive data on the bond dissociation energies of reactions flowing in oxidizing substances in the presence of inhibitors. Autoxidation of hydrocarbons and other organic compounds is a reaction of unique importance for mankind and all living organisms on the earth. Oxidation of organic compounds is one of the important routes of organic synthesis in modern chemical industry. At the same time autoxidation is detrimental in some cases. Keeping and using various chemical products in air often results in their rapid deterioration. There are many such products, including fuels, lubricant oils, rubber, polymers, chemicals, solvents, food stuffs, etc. For this reason, a very important branch of applied science is the chemistry of antioxidants. During the last 30 years free radical reactions of antioxidants were intensively studied by different kinetics methods, and rate constants of hundreds of reactions of peroxyl radicals with phenols, amines etc. were measured. These data constitute the basic ground for kinetic analysis of systems of the type RH + 0 + antioxidants. However many important reactions of antioxidants and their intermediates have not been characterized with kinetic parameters. This problem may be solved by using semiempirical methods of rate constants evaluation. The parabolic model of transition state of free radical reaction was chosen in this Handbook to solve this problem. So the Handbook contains tables with experimentally measured rate constants as well as with those calculated by formulas of parabolic model. The following data are collected in this Handbook: Bond dissociation energies of antioxidants such as phenols (O—H-bonds), aromatic amines (N—H-bonds), hydroxyl amines (O—H-bonds), thiophenols (S—H-bonds); activation energies and rate constants of reactions of peroxyl radicals with antioxidants; rate constants of reaction of phenoxyl, aminyl and nitroxyl radicals with RH, ROOH, phenols, thiophenols, amines and hydroxyl amines; rate constants of reactions of antioxidants with hydroperoxides and oxygen. All information on RH oxidation and antioxidants is divided in to 7 chapters. The first is devoted to short description of mechanism and kinetics of autoxidation of hydrocarbons in the presence of antioxidants , including mechanisms of cyclic chain termination by some inhibitors. It contains the description of the parabolic model of transition state and main formulas for rate constants calculation. The values of rate constants of elementary steps of hydrocarbon autoxidation as well as that of initiators decay, are given in the second chapter. Chapters 3-7 include the thermodynamic and kinetic parameters of reactions of phenols, aromatic amines, hydroxylamines, thiophenols, thiocarbamates and thiophosphates, that are involved in oxidation of hydrocarbons with these compounds. 2

Symbols and units used in Handbook are in accordance with IUPAC recommendation written in the manual, Quantities Units and Symbols in Physical Chemistry, Blackwell Scientific Publications, London, 1988.

Preface All comments, critical notes, and suggestions will be welcomed by the author. Address to send comments to author is the following: Institute of Chemical Physics, Chernogolovka, Moscow Region, 142432, Russia and E-mail: [email protected] I especially thank Taissa G. Denisova for her very valuable help in preparing this manuscript. I am indebted to Vladimir E. Denisov and Sergey V. Foraponov for their help and advice on Microsoft Word Windows. Finally I am grateful to Lyudmila N. Pilipetskaya for her rapid and accurate typing. Chernogolovka, Moscow Region June 19, 1995

Evguenii T. Denisov

CONTENTS PREFACE LIST OF CHEMICAL SYMBOLS LIST OF PHYSICO-CHEMICAL SYMBOLS Chapter

1

1.1 1.2 1.3 1.4 1.5

Chapter

2

Table 2.1

KINETICS AND MECHANISM OF INHIBITED OXIDATION OF HYDROCARBONS

1

Mechanism of autoxidation of hydrocarbons Mechanism of hydrocarbon oxidation inhibited by acceptors of peroxyl radicals Kinetics of inhibited autoxidation of hydrocarbons Mechanisms of cyclic chain termination The parabolic transition state model as semiempirical method of evaluation of activation energies of free radical reactions with hydrogen atom abstraction REFERENCES

14 17

R A T E CONSTANTS OF E L E M E N T A R Y STEPS OF CHAIN OXIDATION OF HYDROCARBONS

19

Enthalpies, activation energies and rate constants of reaction R 0 ' + RH -> ROOH + R*, E calculated by formulas 1.15-1.17, 1.21. The values of A, br and a, see Table 1.6 Rate constants of isomerization and monomolecular decomposition of peroxyl radicals Rate constants of addition of peroxyl radicals to double bond of olefins Rate constants of addition of alkyl radicals to molecular oxygen Rate constants of recombination and disproportionation of peroxyl radical in hydrocarbon solutions Rate constants of disproportionation of two peroxyl radicals of different structure Rate constants of decomposition of azo-compounds into free radicals in liquid phase Rate constants of decomposition of peroxides into free radicals in liquid phase Rate constants of monomolecular decay of hydroperoxides in gas phase and aromatic solvents Rate constants and activation energies of free radical formation by reaction ROOH + Y ->• free radicals

1 2 5 8

2

e

Table

2.2

Table

2.3

Table Table

2.4 2.5

Table

2.6

Table

2.7

Table

2.8

Table

2.9

Table 2.10

19 23 24 27 27 30 32 33 35 35

Contents Table 2.11

Rate constants and activation energies of reaction RH + 0 - » R* + H0 * Rate constants and activation energies of trimolecular reaction 2 RH + 0 -> free radicals REFERENCES

38 39

BOND DISSOCIATION ENERGIES AND R A T E CONSTANTS OF REACTIONS OF PHENOLS

47

2

Table 2.12

2

2

Chapter

Table Table

3

3.1 3.2

O—H-Bond dissociation energies of phenols Enthalpies, activation energies and rate constants of reactions of peroxyl radicals with phenols (Ar,OH) in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of peroxyl radicals with sterically hindered phenols (Ar OH) in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reactions of phenoxyl radicals (AriO*) with secondary and tertiary hydroperoxides in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21. The values of ^4, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of sterically hindered phenoxyls (Ar 0*) with secondary and tertiary hydroperoxides in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reactions of phenoxyls (AriO*) with cumene calculated by formulas 1.15-1.17 and 1.20.The values oL4, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of />ara-methoxyphenoxyl radical (A^O") with sterically hindered phenols (Ar OH) in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of 2,4,6-tert-butylphenoxyl radical (Ar 0*) with different phenols (AriOH) in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Rate constants of reaction of phenoxyl radicals with peroxyl radicals in hydrocarbon solutions, C i 4 H 0 * — peroxyl radical from 9,10-dihydroanfhracene Rate constants of recombination and disproportionation of phenoxyl radicals in hydrocarbon solutions measured by flash photolysis technique Rate constants of disproportionation of two different phenoxyl radicals in hydrocarbon solutions Activation energies and rate constants of reaction of phenols (AriOH) with 0 in hydrocarbon solutions calculated by formula 1.17 alA = 10 1 mol" s" and E = AH

37

47

e

Table

3.3

56

2

e

Table

Table

3.4

3.5

59

e

63

e

65

2

Table

3.6

Table

3.7

e

68

2

e

Table

3.8

70

2

e

Table

3.9

n

Table 3.10

Table 3.11 Table 3.12

2

10

1

1

71

2

73

74 75

76

Contents Table 3.13

Activation energies and rate constants of reaction of sterically hindered phenols (Ar OH) with 0 in hydrocarbon solutions calculated by formula 1.17 at A = 10 1 mol" s" and E = AH Rate constants of reaction of phenols with hydroperoxides Rate constants, preexponential factors and activation energies of decay of quinolide peroxides ROOR; in benzene at 363 K The values of stoichiometric coefficients of chain termination by phenols in oxidizing substances RH REFERENCES

81 83

BOND DISSOCIATION ENERGIES AND R A T E OF REACTIONS OF AROMATIC AMINES

85

2

2

10

Table 3.14 Table 3.15 Table 3.16

Chapter

Table Table

4

4.1 4.2

1

1

78 79 80

CONSTANTS

Dissociation energies of N—H-bonds in aromatic amines Enthalpies, activation energies and rate constants of reaction of peroxyl radicals (R0 *) with aromatic amines calculated by formulas 1.15-1.17 and 1.20. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of aminyl radicals with secondary and tertiary hydroperoxides calculated by formulas 1.15-1.17 and 1.20. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of diphenylaminyl radical with alkylaromatic hydrocarbons calculated by formulas 1.15-1.17 and 1.20. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of aminyl radicals with cumene calculated by formulas 1.15-1.17 and 1.20. The values of A, br and a, see Table 1.6 Rate constants of recombination and disproportionation of aminyl radicals in hydrocarbon solutions measured by flash photolysis technique. Products and mechanism see in papers Rate constants of reaction of paradisubstituted diphenylaminyl radicals with phenols in decane estimated by laser photolysis technique Enthalpies, activation energies and rate constants of reaction between diphenylaminyl radical and aromatic amines calculated by formulas 1.15-1.17 and 1.21. The values of A, br„ and a, see Table 1.6 Rate constants of reaction of aromatic amines with oxygen: AmH + 0 ->• Am* + H0 * calculated by formula 1.17 with A = 3 x 10 1 moP s" per one N—H-bond and E = AH The values of nonstoichiometric coefficients of chain termination by aromatic amines in oxidizing substances RH with cyclic chain termination REFERENCES

85

2

e

Table

4.3

87

e

Table

4.4

90

e

Table

4.5

e

Table

Table

Table

Table

4.6

4.7

4.8

4.9

2

93

94

95

96

2

10

Table 4.10

92

1

1

97

98 99

Contents Chapter

5

Table Table

5.1 5.2

Table

5.3

Table

5.4

DISSOCIATION OF REACTIONS RADICALS

ENERGIES AND R A T E CONSTANTS OF H Y D R O X Y L AMINES AND N I T R O X Y L 101

O—H-Bonds dissociation energies of hydroxylamines Enthalpies, activation energies and rate constants of reactions of secondary alkyl peroxyl radicals with hydroxylamines in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reactions of tertiary alkyl peroxyl radicals with hydroxylamines in hydrocarbons solution calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of hydrogen atom exchange between nitroxyls and hydroxylamines calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reactions of phenoxyl radicals with hydroxylamines in nonpolar solvents calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reactions of sterically hindered phenoxyls with hydroxylamines in nonpolar solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reactions of aminyl radical (4-CH OC6H4) N* with hydroxylamines in nonpolar solutions calculated by formulas 1.15-1.17 and 1.20. The values of A, br and a, see Table 1.6 Rate constants of reactions of alkyl radicals with nitroxyl radicals Rate constants of disproportionation of nitroxyl radicals Enthalpies, activation energies and rate constants of reactions of nitroxyl radicals with hydrocarbons and hydroperoxides in hydrocarbon solutions calculated by formulas 1.15-1.17, 1.20 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reactions of nitroxyl radicals with phenols in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reactions of nitroxyl radicals with sterically hindered phenols in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of nitroxyl radicals with aromatic amines calculated by formulas 1.15-1.17 and 1.20. The values of .4, br and a, see Table 1.6 Rate constants of addition reaction of peroxyl radicals to double bond of nitrones

101

e

107

e

108

e

Table

5.5

110

e

Table

5.6

Table

5.7

e

3

e

Table 5.11

117

2

e

Table 5.8 Table 5.9 Table 5.10

114

120 121 123

125

e

Table 5.12

e

Table 5.13

e

Table 5.14

129

133

137 140

Contents Table 5.15

Rate constants of reaction of hydroxylamines with oxygen: AmOH + 0 - » AmO* + H0 * calculated by formula 1.17 with .4 = 3 x 10 1 m o l s" per one O—H-bond and E = AH REFERENCES

141 143

BOND DISSOCIATION ENERGIES AND R A T E OF REACTIONS OF THIOPHENOLS

145

2

2

10

Chapter

Table Table

6

6.1 6.2

1

1

CONSTANTS

Dissociation energies of S—H-bonds of thiophenols Enthalpies, activation energies and rate constants of reaction of peroxyl radicals with thiophenols in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.20. The values of A, br and a see Table 1.6 Rate constants and stoichiometric coefficients / of reactions of cumylperoxyl radicals with phenolsulfides in cumene Enthalpies, activation energies and rate constants of reaction of C6H S* with hydrocarbons (R3H) and hydroperoxides in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.20. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of /rara-metoxyphenoxyl radical with thiophenols in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.20. The values of A, br and a, see Table 1.6 Enthalpies, activation energies and rate constants of reaction of C H S* with phenols in nonpolar solutions calculated by formulas 1.15-1.17 and 1.20. The values of A, 6 r a n d a , see Table 1.6 Enthalpies, activation energies and rate constants of reaction of nitroxyl radicals with thiophenols calculated by formulas 1.15-1.17 and 1.20. The values of A, br anda, see Table 1.6 Activation energies and rate constants of reaction ArSH + 0 -> ArS' + H 0 ' calculated by formula 1.17 withal = 10 1 mol" s" REFERENCES

145

e

Table

6.3

Table

6.4

146 147

5

e

Table

6.5

Table

6.6

e

6

6.7

e

Table

6.8

150

5

e

Table

149

150

152

10

2

1

Chapter

7

Table

7.1

Table Table

7.2 7.3

Table

7.4

Table

7.5

Table

7.6

2

1

PHOSPHORUS AND SULFUR CONTAINING DECOMPOSING HYDROPEROXIDES

153 154

ANTIOXIDANTS

Rate constants of reaction of peroxyl radicals with phosphines and phosphites in hydrocarbon solutions Rate constants of reaction of hydroperoxide with phosphites Rate constants of reaction of peroxyl radicals with sulfides and disulfides in hydrocarbon solutions The rate constant of reaction of hydroperoxides with sulfides, disulfides and sulfoxides Rate constants of bimolecular catalytic decomposition of hydroperoxides under action of products of oxidation of Scontaining compounds in chlorobenzene Rate constants of trimolecular catalytic decomposition of hydroperoxides under action of products of oxidation of Scontaining compounds in chlorobenzene

155

155 157 158 159

161

163

Contents Table

7.7

Table

7.8

Rate constants of reaction of peroxyl radicals with metal carbamates [R NS ]2Me in hydrocarbon solutions Rate constants of reaction of metalthiophosphates and metalthiocarbamates with cumylhydroperoxide REFERENCES

165 165

INDEX

167

2

2

164

LIST OF CHEMICAL SYMBOLS AmH

aromatic amine

Am*

aminyl radical

AmOH

organic hydroxyl amine

AmO*

nitroxyl radical

Ar,OH

phenol

Ar,0*

phenoxyl radical

Ar OH

sterically hindered phenol

Ar 0'

sterically hindered phenoxyl radical

ArSH

thiophenol

ArS*

thiophenoxyl radical

InH

inhibitor

RH

oxidizing substance

R,H

aliphatic or alicyclic hydrocarbon

R H

olefin hydrocarbon

R H

alkylaromatic hydrocarbon

ROOH

hydroperoxide

R0 *

peroxyl radical

RSH

mercaptane

2

2

2

3

2

LIST OF PHYSICO-CHEMICAL SYMBOLS preexponential factor of rate constant of reaction in its Arrhenius form,

A

expressed

in s"

1

for unimolecular,

in 1 mol

-1

s"

1

for

bimolecular

and in l mol" s" for trimolecular reaction 2

b

t

coefficient

2

1

proportionality

between

potential

of vibration of Mh chemical bond, A, = -rcv, (2 //, )

energy

and

amplitude

1 / 2

D

bond dissociation energy, expressed in kJ mol

E

activation energy of reaction, expressed in kJ mor

e

the probability of radical pair to go out of cage in liquid phase

/

the stoichiometric coefficient of chain termination by inhibitor

AH

enthalpy of chemical reaction, expressed in kJ mol"

h

Planck's constant, h = 6.626 x 10" J s

K

equilibrium constant

k

rate constant of reaction, expressed in s" for unimolecular, in 1 mof

-1

1

1

34

1

1

s

1

for bimolecular and in l mol" s" for trimolecular reaction 2

2

1

L

Avogadro's constant, L = 6.022 x 10

R

gas constant, R = 8.314 J K" mol"

T

absolute temperature, expressed in K

v

rate of chemical reaction, expressed in mol l" s"

a

ratio of b coefficients of dissociating and forming bonds in free radical

1

23

mol"

1

1

1

reaction of H-atom abstraction

1

List of Physico-chemical Symbols P

ratio of rate constants of hydroperoxide decomposition in to free radicals (Ar) 3

and any products (k ), p = k 1 k d

3

d

9

6 = 2.3.R77 kJ mol"

p.

reduced mass of two atoms forming the bond

v

length of the chain in chain reaction

v,

frequency of vibration of i-th bond in molecule

x

induction period of inhibited oxidation

1

Chapter 1 K I N E T I C S AND M E C H A N I S M O F I N H I B I T E D O X I D A T I O N OF HYDROCARBONS 1.1 Mechanism of autoxidation of hydrocarbons The oxidation kinetics and mechanisms of the simplest, though extremely important compounds, hydrocarbons (RH), have been studied in much detail: see, e.g. The early stage of oxidation of an organic compound at the C — H bond resulting in formation of the hydroperoxide consists of the following elementary steps. 1-6

I (initiator) r* + RH R* + 0 R0 * + RH ROOH ROOH + RH ROOH + CH =CHX 2 ROOH R* + R* R* + R0 * R0 * + R0 *

-> ->

->

2

->

->

2

-» -» ->

2

2

->

2

->

(i) (i') (1) (2) (3) (3') (3") (3"') (4) (5) (6)

2

->

2

2

2r* rH + R* R0 * ROOH + R* RO* + HO* RO* + H 0 + R* RO* + HOCH C*HX R0 * + H 0 + RO* RR (or RH + olefin) ROOR ROH + 0 + R'=0 or ROOR + 0 2

2

2

2

2

Oxidation is a chain process, if chain propagation reactions 1 and 2 are faster than chain termination reactions 4-6. Radical R* reacts violently with oxygen, k\ = 10 —10 1 mof s" ; therefore, for oxygen concentrations above 10" M, [R0 *] » [R*] and the chains are terminated by reaction 6. Under these conditions oxidation rate 7

9

1

1

4

2

v

=

+ k (2k T

V i

2

[RH]v,

m

6

(1.1)

1/2

and chain mechanism takes place when initiation rate v, < 0.5 k k ~ [RH] . Quasistationary concentration of peroxyl radicals [R0 *] in oxidizing substance R H is reached in period of time t = 0.74(2£ v,)~ and usually varies from 0.1 to 10 s. When initiator I is the main generator of chains, the rate of oxidation at long chains proceeds with constant rate, if the decay of initiator is negligible, and oxygen is consumed by oxidizing RH with constant rate 2

2

2

2

l

6

s

1/2

2

6

A[0 ] 2

=

fc (2fc )- rRH](MI] ) f 1/2

2

6

1/2

0

(1-2)

When oxidation is proceeding during a long period of time so that the initiator concentration is decreasing and the rate of free radicals generation is changing along the experiment, the kinetics of oxygen consumption A[0 ](f) is described by the following formula A[0 ] = a(l-e- ) (1.3) 2

05kl

2

1

2

Handbook of Antioxidants

where k is the rate constant of initiator decomposition, a = 2k (k /k $ k~ [RH] [ I ] . Autoxidation of hydrocarbons without initiator proceeds with acceleration, that is the result of hydroperoxide formation and its decomposition into free radicals. The chain generation in the initial period of autoxidation proceeds via a very slow reaction RH with oxygen (see Chapter 2). Due to hydroperoxide formation the rate of chain generation is increasing with time and subsequently is increasing the rate of oxidation v ll

2

v

=

1/2

x

0

(

(v, + M R O O H ] )

k (2k T [RH\ m

2

i

0

6

1/2

(1.4)

where v; is the rate of free radicals formation by reaction RH with 0 . Also hydroperoxide is decomposing slowly at its low concentration, so that it is nearly equal to consumed oxygen during some period of time (t « k , k — rate constant of ROOH decay), and at such conditions the kinetics of oxygen consumption is described by the following formula 0

2

_ 1

d

A[0 ] 2

d

=

av t m

i0

(1.5)

+0.25(1%?

wherea = & (2A: )" [RH]. At very low values of v, the kinetics of oxygen consumption has the following simple form: 1/2

2

6

0

(A[0 ])

1/2

2

=

0.5aA:3 f

(1.6)

1/2

The rate of autoxidation is growing up to the moment when hydroperoxide concentration become quasistationary. Beginning at this moment its concentration [ROOH] = [ROOH] and the rate of oxidation is proportional to square of [RH] s

v

=

A: (2fc ) (fc /k )[RH] 2

2

_1

6

3

2

d

(1.7)

and is decreasing in time due to oxidation of RH. 1.2. Mechanism of hydrocarbon oxidation inhibited by acceptors of peroxyl radicals The compounds that inhibit oxidation of hydrocarbons in the liquid phase may be broken up into four groups as regards the mechanism of such inhibition. (1) inhibitors that terminate chains through reactions with peroxyl radicals, including phenols, aromatic amines, hydroxylamines, thiophenols, and aminophenols; (2) inhibitors that terminate chains through reactions with alkyl radicals, including stable radicals, quinones, quinone imines, methylenequinones, nitrocompounds, and condensed aromatic hydrocarbons (these inhibitors are effective when dissolved oxygen concentration is low); (3) agents that decompose peroxides without generating free radicals, including sulfides, disulfides, phosphites, metal thiophosphates, and carbamates; (4) complexing agents that deactivate heavy metals capable of catalyzing hydroperoxide decomposition into free radicals and thereby promoting oxidation, including diamines, amino acids, hydroxy acids, and other bifunctional compounds.

Ch. 1

Inhibited Oxidation of Hydrocarbons

The following reactions take place in with R0 *. ' R0 *+InH In* + ROOH R0 *+In* In* + In* In* + RH InH + ROOH InH + 0 InOOR In* In' + 0 2

7

3

the system upon introduction of InH, which reacts

1 4

2

2

2

ROOH + In* InH + R 0 * products (InOOR) products InH + R* products In* + H0 * InO* + RO* Q + r* Q + H0 *

->

->•

(7) (-7) (8) (9) (10)

2

-> ->

-> ->

2

—>

2

-> -> ->

(11) (12) (13) (14)

2

(15)

2

Reactions i, 1-15, comprise the principal kinetic scheme of inhibited hydrocarbon oxidation. In a given system these reactions take place with different intensities, so some are not as significant as others. If InH is so active and its concentration so high that R 0 * will react faster with InH than with RH, the oxidation will be a non chain radical reaction with rate 2

v

=

v

, + *2 [RH][R0 *]

(1.8)

2

Often, one meets with a different situation: the oxidation is a chain reaction. If In* takes no part in chain propagation but only reacts with R0 *, the oxidation rate is 2

v = v, + k [RH] [R0 *]

=

2

2

v, + v, k [RH] / Jk [InH] 2

(1.9)

1

As more InH is consumed, the oxidation rate will increase and oxygen absorption kinetics will be given by (for current time r k-, 4 / ' [ R H ] 3

8

k [RH] / fc [InH] ,b = 2k k 7

2

a[lnH] (-blnx)

0

2

2Jt [RH]/* [InH]

0

2

7

ft" = 1 + / / 4 ( l + / t a [InH] (-lnx)

2, 8, 14

a{ ( [ I n H ] o " - [ I n H ] " }

2,9,15

[InH] (b(l

2k

0

2

2

0

2)

(l+a)/fen [ 0 ] ) 2

7

2

2

-x)-a\nx)

3

[RH]/fc [InH]o

(9/fe t

2/3

h

0

1

2.7.13

[RH] I fh

n

[RH] /t 2

1 4

3

k

k)

m

7

8

k [RH]/ h [InH]„ 2

ft"' = 1 + [k, k (1 + a ) [ I n H ] ] " 9

0

2

[0 ] ) 2

and (iii) the mechanism remains unchanged through the induction period. Since the rate of inhibitor consumption v = v, / / and v, tends to increase during oxidation, the InH consumption kinetics is substantially nonlinear. During the early stages of oxidation vinH v,- o / / but as more ROOH is accumulated increases and becomes maximum toward the end of the induction period. Calculation and experiment yield identical results. At a sufficiently high temperature or in the presence of a ROOH decomposer, ROOH will rapidly dissociate and therefore the oxidation regime will quickly become quasi-steady as regards the ROOH concentration, with the decomposition rate equal to the rate of its formation. However, the ROOH concentration will tend to increase, since as more InH is consumed, the inhibition effect will decline and the ROOH formation rate will increase. A necessary condition for the quasi-steady process is the inequality k x » 1, where k is the total rate constant of ROOH consumption by all possible routes, including dissociation to radicals, decomposition to molecular products, and decomposition under attack of free radicals. The change from a nonsteady to the quasi-steady condition is related to the induction period r , which depends on the InH type and concentration. The transition from one inhibitor to another often manifests itself in transitions from one type of autoxidation process to another and various critical phenomena. What we mean by critical effects in inhibited autoxidation of RH is that under a certain critical InH concentration [InH] there takes place a sharp change in the r vs. [InH] relationship; i.e., dr/d[InH] for [InH] > [InH] is much greater than dr/d[InH] for [InH] < [InH] . Critical effects may arise when (i) inhibited oxidation proceeds via mechanisms, that include chain termination by reaction 7 (see Table 1.3), (ii) hydroperoxide is the main initiating agent so that v « & [ROOH], and (iii) decomposition of ROOH InH

=

d

d

15

cr

cr

cr

JO

3

Ch. 1

Inhibited Oxidation of Hydrocarbons

7

is sufficiently rapid so the condition k » r" for [InH] > [InH] is satisfied. As we have said earlier the critical phenomena are due to the feedback effect in inhibited oxidation and occur when both the formation and decomposition rates are similarly dependent upon [ROOH], for example, when they are directly proportional to [ROOH]. If the oxidation rate is proportional to [ROOH]", with n < 1, and the decomposition rate is proportional to [ROOH], the critical effects will never take place. Table 1.3 contains formulas for chain lengths v, [InH] and the quasi-steady hydroperoxide concentration [ROOH] for different inhibited oxidation mechanisms. The table 1.4 also contains formulas for the induction periods of inhibited autoxidation. The induction period was calculated as the time of InH decrease from [InH] to [InH] (mechanisms 1, 3, 5) or to zero. 1

cr

3

cr

3

0

cr

One may obtain a synergistic effect in inhibition of autoxidation of RH if two different InH, one of which acts to terminate the chains (ArOH, AmH) and the other of which decomposes hydroperoxides (sulfide, zinc carbamate, etc.,) are added to RH. In combination the two InH are operative for a longer period than either of them separately because one of them decelerates the buildup of ROOH by breaking the chains and the other, by decomposing ROOH, reduces v, and slows down the consumption of the first InH. Antioxidant of complex function, containing groups reacting, with both R0 " and ROOH, may be expected to be highly effective. 2

Table 1.3 Formulas for kinetic parameters of hydrocarbon autoxidation as chain reaction in quasistationarv regime: chain length v, critical concentration of inhibitor [ I n H ] , and quasistationarv concentration of hydroperoxide [ROOH];. The following symbols are used: fi = k^/k and v is rate of free radical generation on reaction of R H with oxygen cr

l0

d

Key steps

|InH]„

v

2,7

k [RH] Ifh

[InH]

2,8,10

/)-'

2,-7,8

/t ^7" [RH](/*3*7^[InH])"

2, 7, 11

k [RH] lfk

2, 7, 12

k [RH] lfk

2

[ROOH],

p k [RH] Ifk 2

P v v,• / h (1 - /} v) 0

n

— 2

2

2

n

2

n

2

fi k l

[InH]

0k

2

2

2

2

s

8

{([InH]/[InH]„) - 1}

v /fk,

2

pk

10

2

7

[InH]

3

1

k. [RH) /fk k k

2 2

fc [RH] //^/t7/t [InH]

pk t 0

[RH] / / i t ,

pw, / ( l - / 9 v)(kj + k

[InH])

[RH] Ifk-,

0 v{ v , + k [0 ][InH]

)/

0

n

0

2

l2

/h(\-Pv) 2.7, 13

k [RH] lfk

2.8, 14

(T

2,9,15

t [0 ](2fc v or" (2+k ^ [RH][InH]" )

2

[InH]

7

[RH] Ifk

0k

2

0



l

2

1 5

2/? v v , / k , (1 - 2/? v)

7

2

9

i

1

2

1

Pkk 2

ti [RH])

k (2k v ) (f)k m

7

9

i0

-2k 'k 2

7

5

2

[0 ][RH] 2

1

_ 1

[RH] /fky

fe,/t [InH]

2

2

14

p vv

j 0

/ k, (1 -0

8

v)

8

Handbook of Antioxidants Table 1.4 Formulas for induction period rof inhibited oxidation of hydrocarbons in quasistationarv regime. Symbols are the following: to = f [InH] v, o", p = ki /ki, v, is the rate of free radical generation on reaction of R H with oxygen 1

0

Key steps

0

x/xo

2, 7, 8

1 -x"

2.8.10

1-x"

2.7.11

[ I n H M I n H ^ - alnx

1

( 1 + Inx)

fk

ln(l+;c)

1

[InH] //?fa [RH] 0

n

/Jt,i [InH] v,o//? fc2 MRH] 2

8

2

3

0

ife,, [ I n H ^ + ft)[InHV(t

7

k

n

[ I n H ] + 6)[InH] ; 0

a = Ph [RH][(/[InH]oXfe"'

b =k kn +Pk k 3

2, 7, 12

2

u

[RH] ) " ' ;

[RH]

u

ex' (2 - b/a ) {arc tan [ c(2ax + b)] -

fk-, [InH] //?fe [ R H ] ,

arc tan [ c (2a + b )]}

a =fh

1

+ 0k

CT

0

k

[0 ][InH]„ , b = v k [InH]„, 2

l2

2

ia

1

c-' = b [4 (/- - 1) * „ [0 ][InH]„ v - ' - l ] " 2

2, - 7 , 8

1 - x " { 1 + In (2 - 2x

2,8,14

l-x'ln(l+x)

1

m

+x) + arctan(x" - 1 ) 2

fh k fc [InH] / / ? f e i _ [ R H ]

2

/yt 2, but as experience shows, for oxidizing hydrocarbons / < 4 for hydroquinones, amines, and diamines of the p-phenylenediamine type. At the same time there are inhibitors that in a given system cause catalyzed termination of chains and in this case / » 2 . Multiple chain termination was observed in oxidizing cyclohexanol with a-naphthylamine. This was shown to be typical of a number of aromatic amines in primary and secondary alcohol oxidation. The range of compounds in oxidation of which the InH becomes involved in multiple chain terminations is rather broad and includes also cyclohexadiene, primary, secondary, and tertiary aliphatic amines, cyclohexanone containing hydrogen peroxide, and 1,2-disubstituted ethylenes. For these compounds f » 2 with AmH, nitroxyl radicals, certain ArOH, and quinones used as InH. The high nonstoichiometric values of / are due to the catalytic mechanism of chain termination occurring in such systems. The mechanism itself is due to the dual function of hydroxyperoxyl, aminoperoxyl, and hydroperoxyl radicals, which may either oxidize or reduce. 16

3,17,18

19

20

21

22,23

24

25

Ch. 1

Inhibited Oxidation of Hydrocarbons

9

The pure catalytic chain termination occurs on copper ions in oxidizing cyclohexanol. >C(OH)00'+ C u >C(OH)00* + C u

+

2+

->

>C(OH)00 + C u

->

>C=0 + 0 + C u + H

26

(16)

2+

+

(17)

+

2

The value of rate constants of hydroxyperoxyl radical reactions with metallic ions and complexes are summarized in Table 1.5. Table 1.5 Rate constants of peroxyl radical reaction with metal complexes Metal complex

Oxidizing substance

77 K

kl 1 mol's

Ref. 1

Manganese (II) stearate

cyc/o-[CH=CHCH=CH(CH ) ]

348

1.9 x 10

6

19

Manganese (II) stearate

cyc/o-CsHnOH

348

2.4 x 10

6

59

Manganese (II) acetate

(C H ) NH

348

2.5 x 10

6

60

Manganese (II) stearate

(C H,) NH

348

3.5 x 10

6

24

Manganese (II) acetate

cyc/o-C H NH

348

7.3 x 10

7

2

60

Manganese (II) stearate

cyc/o-C H NH

348

1.6 x 10

s

2

24

Bis-(acetylacetonate)manganese (II)

cyc/o-C H NH

363

9.8 x 10

7

2

61

N,N'-Ethylene-bis-(salicylideneiminato)manganese (II)

cyc/o-C«HnNH

348

3.1 x 10"

61

Manganese (II) acetate

C H CH NH

338

2.8 x 10"

60

Manganese (II) acetate

CH =C(CH )C(0)0C R,N(CHi)

323

1.2 x 10

7

62

Manganese (II) acetate

C H,OCOCH CH N(CH )

323

1.5 x 10

7

62

Bis-(dimethylglioximato)-bis-pyridineferrous

cyc/o-[CH=CHCH=CH(CH ) ]

348

2.3 x 10

3

63

Bis-(dimethylglioximato)-bis-pyridineferrous

(CH,) CHOH

344

1.0 x 10

3

64

Ferric stearate

cyc/o-C HnOH

348

4.8 x 10

3

59

Ferric stearate

cyc/o-C HnNH

2

348

1.2 x 10*

24

Tris-(acetylacetonate)ferric

cycto-C HnNH

2

348

1.0 x 10"

60

Bis-(dimethylglioximato)ammineiodidecobalt (II)

cyc/o-[CH=CHCH=CH(CH ) ]

348

2.3 x 10"

63

Bis-(dimethylglioximato)amminechloridecobalt

cyc/o-[CH=CHCH=CH(CH ) ]

348

8.4 x 10

2

63

Tris-(dimethyIglioximato)cobaIt (III)

(CHj) CHOH

344

2.9 x 10

2

64

Bis-(dimethylglioximato)ammineiodidecobalt (II)

(CH ) CHOH

344

3.1 x 10

2

64

Bis-(dimethylglioximato)pyridineiodidecobalt (II)

(CH ) CHOH

344

7.0 x 10"

64

2

4

9

2

2

4

2

6

6

6

6

3

u

n

u

2

2

2

2

3

3

2

2

2

3

2

2

2

2

6

6

6

(II)

2

2

2

3

3

2

2

2

2

2

10 Metal complex

Handbook of Antioxidants Oxidizing substance

Rel

Tl K

1 mol-•s"

1

Bis-(dimethylglioximato)amminechloridecobalt (II)

(CH ) CH0H

344

5.0 x 10

3

64

Bis-(dimethylglioximate)-bis-pyridinecobalt (II)

(CH ) CHOH

344

1.2 x 10

4

64

Cobalt (II) stearate

cyc/o-C H OH

348

1.0 x 10

5

59

Cobalt (II) chloride

cyc/o-C H„OH

348

6.2 x 10

4

19

Cobalt (II) acetate

cyc/o-C H„OH

348

1.3 x 10

5

19

Cobalt (II) stearate

cyc/o-C H OH

348

3.1 x 10

4

19

Cobalt (II) cyclohexylcarboxilate

cyc/o-CsHnOH

348

8.9 x 10"

19

Bis-(acetylacetonato)cobalt (II)

cyc/o-C H„OH

348

6.4 x 10

4

60

N,N'-Ethylene-bis-(salicylideneiminato)cobalt (II)

cyclo-CHuOH

348

3.3 x 10

5

61

Porfirine cobalt (II)

cyclo-CeUuOU

348

3.6 x 10"

61

Bis-(salicylate) nickel

C H OH

363

1.6 x 10

4

61

Bis-(salicylate) nickel

cydo-C H NH

353

2.8 x 10

4

61

N,N'-Ethylene-bis-(salicylideneiminato)nickel

C H„OH

363

7.9 x 10

3

61

N,N'-Ethylene-bis-(salicylideneiminato)nickel

cyc/o-C HnNH

353

1.5 x 10

4

61

N,N'-Ethylene-bis-(salicylideneiminato)nickel

C H OH

363

3.5 x 10

4

61

N,N'-Ethylene-bis-(salicylideneiminato)nickel

cyc/o-C

>NOH + ROO'

>NOH + HN=C< + 0

(20)

2

>NO* + ROOH

(21)

It is remarkable that oxidation-reduction activity is also exhibited by peroxyls that have next to their peroxyl group a heteroatom with a lone electron pair or a double bond. Such peroxyls probably react with the inhibitor radical, quinone, or variable-valence metal ion by way of electron transfer, e.g. >C(00')NHR + C u

2+



>C(00 )NHR *+Cu ,

+

1+

(22)

followed by rapid elimination of the proton and oxygen molecule >C(00 )N HR ,

,+

->

>C=NR + 0 + H

+

2

(23)

All the peroxyls we have mentioned decompose, generating H0 * 2

>C(OH)00* >C(NH )00* 2

->

>C=0 + H 0 ' >C=NH + H0 * 2

2

(24) (25)

12

Handbook of Antioxidants

Thus, generated in the system and participating in catalyzed chain termination (if the corresponding InH has been added) are both hydroxyperoxides and hydroperoxides. Depending on the type of compound and oxidation conditions (temperature, degree of conversion), either H0 * or >C(OH)00* [>C(NH )00*] radicals may preferentially take part in chain termination. Things are just the same with chain termination in oxidizing amines. Aliphatic and alkyl aromatic peroxyl radicals do not take part in reactions of this sort because they have no reducing activity. Since the hydroxyperoxyl (hydroperoxyl, aminoperoxyl) radical behaves as both an oxidant and a reductant, it will react with In* by two parallel routes. In the case of AmH the following three mechanisms of chain termination appear to be probable. 2

2

37

Ar NH + Ar N* + Ar N* + Ar NO* + Ar NOH + CsHjArN* + OCsRrNAr + ArNHCftO* +

(i)

2

2

(ii)

2

2

2

(iii)

HO('00)CR HO(*00)CR HOCOO)CR HO(*00)CR HO(*00)CR HO('00)CR HO(*00)CR HO(*00)CR

2

-> -» -» -»

2

->•

2

2

2

2

2

2

2

2

2

2

2

2

2

2

-» -» ->

(26) (27) (28) (29) (30) (31) (32) (33)

Ar N* + R C(OH)OOH Ar NH + 0 + R C = 0 Ar NO* + HO('0)CR Ar NOH + 0 + R C = 0 Ar NO" + R C(OOH)OH ArN=CfiH,0 + R C O + H 0 ArNHC^O* + 0 + R C=0 ArNCg^O + R C(OOH)OH 2

2

2

2

2

2

2

2

2

Multiple involvement in chain termination reactions has also been observed for the stable nitroxyl radicals 2,2,6,6-tetramethylpiperidin-N-oxyl and its derivatives. Nitroxyl radicals (>NO") break the chains in oxidizing hydrocarbons and polymers by reacting with alkyl radicals. 38

>NO* + R*

->

>NOR

(34)

If we accept this mechanism, the rate of inhibited polymer oxidation must be v = k, [0 ]v, /k [>NO*]. The k^lk, ratio for 2,2,6,6-tetramethyl-4-benzoylpiperidin-N-oxyl equals 0.09 in polypropylene at 387 K and 0.027 in polyethylene at 365 K . Nitroxyl radicals react slower than oxygen with alkyl radicals, and their high inhibiting effect in polymers is due to the relatively low dissolved oxygen concentration in polymers. The multiple involvement of >NO* in chain termination manifests itself in the fact that the rate of >NO* consumption in a polymer is much smaller than the rate of initiation under conditions where all the chains are terminated via reaction alkyl radical with nitroxyl. ' Under the same conditions, but in the absence of oxygen, the nitroxyl radical is consumed at a rate equal to that of initiation. In an initiator-containing polymer all the nitroxyl radicals will be consumed within a time equal to [>NO*] / v, (as monitored by ESR). However, >NO* reappears in the system to which oxygen has been admitted, under attack of R 0 * . Regeneration has been proposed to be due to the following reaction 2

34

3 9

38

39

0

38,39

2

65

R0 * + HCCON< 2



ROOH + >C=C< + >NO*

(35)

This supposition is consistent with the following data. The >NO* are formed from the products of reaction between the alkyl macroradical with >NO* only in the presence of 0 and initiator, that is, under attack of R0 *. The product cannot be the corresponding hydroxylamine since it could not be extracted from the polymer with a solvent. The following reaction has been demonstrated experimentally. 2

2

40

[(CH ) C] NOC(CH )3 + *0 C(CH ) 3

3

2

3

2

3

3

-> [(CH ) C] NO* + CH =C(CH ) + H 0 C ( C H ) 3

3

2

2

3

2

2

3

3

(36)

Ch. 1

Inhibited Oxidation of Hydrocarbons

13

The k value is rather high; it is 44 1 mol" s" at 403 K in ferr-butylbenzene. The scission of the weaker secondary C — H bond should have been faster. A different regeneration mechanism was proposed in ref. 40, where it was noted that hydroxamic ether was thermally unstable and dissociated at the O — C bond, which was followed by cage disproportionation of radicals 1

1

36

R NOC(CH ) 2

3

->

3

[R NO* + HCH C*(CH ) ] 2

2

3

->

2

R NOH + CH =C(CH ) 2

2

3

(37)

2

By reacting with R0 * hydroxylamine was converted to >NO*. Below 400 K decomposition of hydroxamic ethers is slow (at 403 K it is decomposed with rate constant & = 5.7 x 10"' s" ) and cannot be responsible for the experimentally observed regeneration rates. Besides, under the conditions that had been used in the polypropylene experiments this mechanism runs contrary to some of the above factors. Yet at a higher temperature when hydroxamic ether decomposes faster, this mechanism might possibly become effective. An increase of the stoichiometric coefficient / has also been observed for ArOH in polymers as the partial 0 pressure was reduced. For example,/ = 1 and 3.3 for a-naphthol in oxidizing polypropylene at 388 K at Po =100 and 0 kPa, respectively. The reason is that the reduction of [0 ] increases the fraction of ArO* reacting with alkyl radicals, which not only recombine but also disproportionate 2

40

37

1

39

2

41

2

2

ArO" + R CHCR * 2

2

->

ArOH + R C=CR 2

(38)

2

Thus the mechanisms by which the inhibitor radicals are regenerated in chain termination are quite varied. The acid catalyzed cyclic chain termination by nitroxyl radicals were found in oxidizing hydrocarbons recently. Inhibiting system includes nitroxyl radical, hydrogen peroxide and organic acid. Effective chain termination provoke only triple system and binary systems (AmO* + H 0 , AmO* + acid (HA), H 0 + acid) have very weak inhibiting effect on ethylbenzene oxidation. Hydrogen peroxide is consumed during induction period and nitroxyl radical and acid practically are not decomposed during oxidation. The following mechanism was proposed. 42,43

2

2

2

AmO* + HA R0 * + AmOH* , A" -> AmO, A" + H 0 ->• R0 * + AmOH -> +

2

2

2

2

2

(39) (40) (41) (42)

AmOH* + A" ROOH + AmO , A AmOH + 0 + HA ROOH + AmO* +

+

2

Protonization of nitroxyl radical transforms it into the form reactive toward peroxyl radical and formed nitronium ion is reduced fast by hydrogen peroxide. These two reactions together with fast reaction of formed hydroxyamine with R 0 * give rise the cycle of effective chain termination. The same mechanism apparently takes place when the triple system: alcohol + nitroxyl radical + acid is introduced into oxidizing hydrocarbon. Very close to this mechanism is that of another triple inhibiting system: iminoquinone (Q) + hydrogen peroxide + acid. The following mechanism is proposed for action of this system. 2

42

44

Q + HA R 0 * + QH*, A" Q* , A" + H 0 R0 * + *QH 2

+

2

2

2

-» -> ->

Q l T + A" ROOH + Q* ,A *QH + 0 + HA ROOH + Q +

2

(43) (44) (45) (46)

14

Handbook of Antioxidants 1.5 The parabolic transition state model as semiempirical method of evaluation of activation energies of free radical reactions with hydrogen atom abstraction

Among different empirical and semiempirical methods of evaluation of rate constants the parabolic transition state model of free radical reaction of atom abstraction is rather simple, convenient and gives reliable results. The main theses of this conception are the following. ' In a reaction of the type 45

45

46

R* +HRi

->

f

RfH + R ;

(47)

the R,—H bond is being broken and the R — H bond is being formed. According to the theory of absolute rates, the reaction may be treated as a translation of the hydrogen atom along the reaction coordinate from an initial position at x = 0 with potential energy U (0) = 0 to its final position at x = r and U (r ) = A / f , where AH is the reaction enthalpy, with zero energies taken into account, so f

t

e

t

ei

e

AH

ei

=

ei

Di -D

+0.5hL(y,

f

(1.15)

-v ) f

where A and 73/ are the dissociation energies of the R,—H and R(—H bonds, v, and v/ are their vibration frequencies, h is Planck's constant and L is Avogadro's number. Let us consider the vibration of atoms along the R,—H and R,—H bonds to be harmonic, so that Uj = bi x and U = b (r - x) , b , = TTV, (2fi, ) , and b = nv (2ju f where / / , and JU/ are the reduced masses of the atoms. The transition state is proposed to be represented by the point of intersection of two undisturbed potential curves atx = r*, when E = C/,- ( / ) = U (r - r* ) -Aff The activation energy E is related to the observed E by the equation. 1/2

m

1 / 2

m

f

f

ei

t

e

2

f

e

f

f

ei

f

ei

f

E

=

e

(1.16)

E + 0.5{hViL-RT)

Activation energy E in its turn may be calculated on the value of experimentally found rate constant k using Arrhenius equation {

E

=

(1.17)

RTln(A/k)

where A is preexponential factor of a given group of free radical reaction known from experimental measurements. The important characteristic of the transition state is the distance r which may be estimated in the form br using eqn. (1), where a = b /b = v v / (ju I ju ) e

e

1

t

7

f

m

f

f

=

b r t

e

a (E„ - AH )

+ E.

1/2

ei

(1.18)

1 / 2 t

The activation energy of the thermoneutral reaction in the given series may be calculated, using eqn. E

(6,r ) (l+a)-

=

eo

2

The parameterft,r allows us to calculate E e

E

ei

ei

=

(1.19)

2

e

for any reaction using eqn. (1.20).

(6,r ) (l-a )- {l-a[l-(l-a )(ft,A- )- Ar7 ] 2

e

2

2

2

2

e

e

1 / 2

}

2

(1.20)

Ch. 1

Inhibited Oxidation of Hydrocarbons

Eqn. 1.20 takes it simplest form when AH « e

Eei

=

1/2

15 (b r f t

e

(1-a ) 2

h r (1 + a

1

+ a AH

e

(2b r )

ei

t

_ 1

e

(1.21)

The above equations are valid for calculating activation energy of any free radical reaction with AH that is limited by minimum and maximum values, namely at a = 1. e

AH AH

emin

=

b,r (

2hLv, )

emax

=

(b.re)

e

m

2

e

-hr.QhLv,)"

2

(1.22)

- ( b,r )

(1.23)

2

At AH < AH min activation energy E = 0, and at AH > AH activation energy E = AH. These equations were used to calculate rate constants of hydrogen atom abstraction from RH, ArOH, AmH etc. by different radicals, that are generated in oxidizing hydrocarbons in the presence of inhibitors. The values of parameters br , , E„ and r are given in the Table 1.6. All these values were calculated from experimental data (rate constants) in hydrocarbon solutions. e

e

e

e

e

m a x

0

e

Table 1.6 Kinetic parameters of free radical reactions with hydrogen atom abstraction in the parabolic model of transition state Reaction

br l (kJmol"')" t

a

Al Imol's"'

E„/ k.Jmol '

r xlO / m

b,/(bi + b,)

2

u

e

R ( V + R,H

14.23

0.814

1.0 x 10

s

61.5

3.802

0.449

R0 " + R H

15.68

0.814

1.0 x 10

7

74.7

4.189

0.449

R0 "

+R H

14.74

0.814

1.0 x 10

7

66.0

3.938

0.449

R0 '

+ROOH

13.13

1.00

1.0 x 10

s

43.1

2.854

0.500

R0 '

+Ar,OH

13.46

1.00

3.2 x 10

7

45.3

2.885

0.500

R 0 ' + Ar OH

14.40

1.00

3.2 x 10

7

51.8

3.087

0.500

R0 " + AmH

12.12

0.940

1.0 x 10

s

39.0

2.802

0.485

R0 '

13.50

1.00

3.2 x 10

7

45.6

3.318

0.500

ROj* + ArSH

10.39

0.658

3.2 x 10

7

39.3

3.434

0.420

Ar!0 + R H

15.53

0.802

1.0 x 10

8

74.3

4.162

0.445

Ar!0' + Ar OH

13.31

1.00

1.0 x 10

s

51.6

3.080

0.500

AriO" + AmH

10.13

0.927

1.0 x 10"

27.6

2.343

0.481

Ar,0*+AmOH

12.93

1.00

1.0 x 10*

41.8

2.772

0.500

Ar,0*+ROOH

13.46

1.00

1.0 x 10

8

45.3

2.926

0.500

AriO*+ArSH

10.48

0.649

1.0 x 10

8

40.5

3.463

0.606

2

2

2

3

2

2

2

2

2

+ AmOH

2

-

3

2

16

Handbook of Antioxidants

Reaction

brj (hJmor )"

Al 1 mol

1

E J klmol" t

s

1

H

1

r, x 10"/ m

b,/(b, + b,)

Ar 0*+R H

18.06

0.802

1.0 x 10"

100.4

4.823

0.445

A r 0 * + A n OH

13.31

1.00

1.0 x 10

s

44.3

2.853

0.500

Ar 0"+ Ar OH

14.37

1.00

1.0 x 10

8

51.6

3.080

0.500

A r 0 ' + AmOH

14.54

1.00

1.0 x 10

8

52.9

3.117

0.500

Ar 0*+ROOH

14.40

1.00

3.2 x 10

7

51.8

3.130

0.500

A r 0 * + AmH

11.26

0.927

1.0 x 10

s

34.2

2.605

0.481

Am" + AmH

11.63

1.00

1.0 x 10

8

33.8

4.233

0.500

A m ' + AmOH

11.97

1.079

1.0 x 10

7

33.2

2.566

0.519

Am'

+ROOH

12.89

1.064

1.0 x 10

s

39.0

2.802

0.515

Am*

+R H

16.87

0.866

1.0 x 10

8

81.7

4.507

0.464

AmO*+Ar,OH

12.93

1.00

1.0 x 10

8

41.8

2.772

0.500

AmO* + A r O H

14.54

1.00

1.0 x 10"

52.9

3.117

0.500

AmO* + AmH

11.10

0.927

1.0 x 10

8

33.2

2.568

0.481

AmO" + AmOH

12.61

1.00

3.2 x 10

7

39.8

2.703

0.500

AmO" + ROOH

13.50

1.00

1.0 x 10

8

45.6

2.894

0.500

AmO"+R,H

13.72

0.802

1.0 x 10

9

58.0

3.665

0.445

AmO"+ R H

15.66

0.802

1.0 x 10

8

75.5

4.184

0.445

AmO"+R H

14.42

0.802

1.0 x 10

s

64.0

3.852

0.445

AmO* + ArSH

11.58

0.649

1.0 x 10

8

49.3

3.827

0.394

ArS" + AmOH

17.84

1.541

1.0 x 10

s

49.3

3.827

0.606

ArS* + A r , O H

16.07

1.534

1.0 x 10

8

40.2

3.768

0.395

ArS"

15.79

1.520

3.2 x 10

7

39.3

3.433

0.603

13.74

1.238

1.0 x 10

8

37.7

3.668

0.553

2

3

2

2

2

2

2

2

3

2

2

3

+ROOH

ArS* + R H 3

Ch. 1

Inhibited Oxidation of Hydrocarbons

17

REFERENCES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

30 31 32 33

Ingold, K . U . , The retarding action of inhibitors on autoxidation of organic compounds in liquid phase, Chem. Rev., 61, 563, 1961. Emanuel, N. M., Denisov, E . T., Maizus, Z . K . , Liquid Phase Oxidation of Hydrocarbons, Plenum, New York, 1967, Chap. 7. Denisov, E . T., Mitskcvich, N. I . , Agabekov, V. E . , Liquid-Phase Oxidation of Oxygen-Containing Compounds, Consultants Bureau, New York, 1977, Chap. 2. Mill, T., Hendry, D. G., In Comprehensive Chemical Kinetics, Elsevier, Amsterdam, vol. 16, 1980, Chap. 1. Emanuel, N. M., Zaikov, G . E . , Maizus, Z. K . , Oxidation of Organic Compounds. Effect of Medium, Pergamon, Oxford, 1984, Chap. 7. Kucher, R. V., Opeida, I . A., Cooxidation of organic compounds in liquid-phase, Naukova Dumka, Kiev, 1989, 208 (in Russian). Landberg, W. O., Ed., Autooxidation and Antioxidants, Interscience, New York, 1962, vol. 1. Scott, G., Atmospheric Oxidation and Antioxidants, Elsevier, Amsterdam, 1965, Chap. 4. Howard, J . A., Absolute rate constants for reactions of oxyl radicals, Adv. Free Radical Chem., 4, 49, 1972. Denisov, E . T., Kovalev, G. I . , Oxidation and Stabilization of Jet Fuels, Khimiya, Moscow, 1990, 270 (in Russian). Roginskii, V. A., Phenolic antioxidants. Reactivity and effectiveness, Nauka, Moscow, 1988, 248 (in Russian). Denisov, E . T., Oxidation and degradation of carbonchain polymers, Khimiya, Leningrad, 1990,287 (in Russian). Scott, G . , Ed., Mechanism of polymer degradation and stabilization, Elsevier Applied Science, London, 1990, 329. Denisov, E . T., Khudyakov, I. V., Mechanism of action and reactivity of the free radicals of inhibitors, Chem. Rev., 87, 1313, 1987. Emanuel, N. M., Gagarina, A. B., Critical phenomena in chain reaction with degenerate branching, Usp.Khim., 35, 619, 1966. Denisov, E. T., Liquid-Phase Reaction Rate Constants, Plenum, New York, 1974, Chap. 6. Denisov, E . T., Regeneration of inhibitors and negative catalysis in chain reactions of oxidation, Kinet. Katal, 11,312, 1970. Denisov, E . T., in Developments in polymer stabilization-^, Applied Science Publishers, London, 1979, Chap. 1. Denisov, E . T., Kharitonov, V. V., Peculiarities of retarding action of 1-naphthylamine in oxidizing cyclohexanole, Izv. Akad. Nauk SSSR., Ser.Khim., 2222, 1963. Denisov, E . T., Scheredin, V. P., Synergistic action of alcohols on inhibiting activity of aromatic amines, Izv. Akad. Nauk SSSR, Ser.Khim., 919, 1964. Vardanyan, R. L . , Denisov, E . T., Regeneration of inhibitors in oxidizing 1,3-cyclohexadiene, Izv. Akad. Nauk SSSR, Ser. Khim., 2818, 1971. Kovtun, G . A., Alexandrov, A. L . , Oxidation of aliphatic amines by molecular oxygen in liquid phase. 1. Kinetic of oxidation of primary and secondary amines., Izv Akad. Nauk SSSR,Ser.Khim., 2208, 1973. Kovtun,G. A., Alexandrov, A. L . , Oxidation of aliphatic amines by molecular oxygen in liquid phase . 4. Regeneration of inhibitors in oxidizing tertiary amines, Izv. Akad. Nauk SSSR, Ser. Khim., 1274, 1974. Kharitonov, V. V., Denisov, E . T., The dual reactivity of hydroxyperoxyl radicals in reaction with aromatic amines, Izv. Akad. Nauk SSSR, Ser. Khim., 2764, 1967. Sokolov, A. B., Nikanorov, A. A., Pliss, E . M., Denisov, E . T., Effect of multidipoles interaction in reactions with peroxyl radicals, Izv. Akad. Nauk SSSR, Ser. Khim., 778, 1985. Alexandrov, A. L . , Denisov, E . T., Negative catalysis by cupric ions in chain oxidation of cyclohexanole, Izv. Akad. Nauk SSSR, Ser. Khim., 1652, 1969. Alexandrov, A. L . , Solov'ev, G . I . , Denisov, E . T., Negative catalysis by heavy metal stearates in chain oxidation of cyclohexanole, Izv. Akad. Nauk. SSSR, Ser. Khim., 1527, 1972. Kovtun, G . A., Lukoianova, G . L . , Berenblum, A. S., Moiseev, I. I . , Antioxidative properties of nickel complexes of salicylaldoximes, Dokl. Akad. Nauk. SSSR, 231, 656, 1976. Kovtun, G . A., Alexandrov, A. L . , Denisov, E . T., Oxidation of aliphatic amines by molecular oxygen. Kinetics of regeneration of inhibitors in oxidizing primary and secondary amines., Izv. Akad.Nauk. SSSR, Ser.Khim., 2611, 1973. Kovtun, G . A., Complexes of transition metals as catalysts of chain termination in oxidation, Doct. Sci. (Chem.) Thesis Dissertation, Moscow, 1984, p. 14-24 (in Russian). Pliss, E . M . , Alexandrov, A. L . , Negative catalysis by heavy metals in oxidizing tertiary aliphatic amines., Izv. Akad. Nauk. SSSR, Ser. Khim., 214, 1978. Zubareva, N . G., Denisov, E . T., Ablov, A. V., Negative catalysis by dioximines of transition metals in oxidizing 1,3-cyclohexadiene, Kinet. Katal.,14, 579, 1973. Zubareva, N. G . , Denisov, E . T., Ablov, A. V., Negative catalysis by dioximines of transition metals in oxidizing isopropanole., Kinet. Katal.,\4, 346, 1973.

18 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Handbook of Antioxidants Kovtun, G. A., Mechanism of oxidation of aliphatic amines and regeneration of antioxidants. Cand. Sci. (Chem.) Thesis Dissertation, Inst. Chem. Phys., Chernogolovka, 1974, 164 (in Russian). Denisov, E . T., Mechanism of inhibiting action of quinone in chain oxidation of isopropanole, Izv. Akad. Nauk SSSR, Ser. Khim.,12%, 1969. Kovtun, G . A., Golubev, V. A., Alexandrov, A. L . , Kinetic study of regeneration of nitroxyl radicals in primary and secondary amines, Izv. Akad.Nauk SSSR, Ser. Khim.,793, 1974. Denisov, E . T., Goldenberg, V. I . , Verba, L . G., Mechanism of cyclic chain termination and intermediates of aromatic amines in oxidizing isopropanole and ethylbenzene, Izv. Akad. Nauk SSSR, Ser. Khim., 2217, 1988. Shilov, Y u . B., Battalova, R. M., Denisov, E . T., Regeneration of nitroxyl radicals in oxidizing polypropylene, DoklAkad. Nauk SSSR, 207, 388, 1972. Shilov.Yu. B., Denisov, E . T., Mechanism of inhibiting action of nitroxyl radicals in oxidizing polyethylene and polypropylene, Vysokomol. soedin., SerA , 16, 2313. 1974. Berger, H., Bolsman,T. A. B. M., Brouwer, D. M., in Developments in polymer stabilization-6, Ed. Scott G., Applied Science Publishers, London, 1983, Chap. 1. Zolotova, N. V., Denisov, E . T., Kinetic peculiarities of inhibiting action of phenols in polypropylene oxidation, Vysokomol. soedin., Ser.B, 18, 605, 1976. Goldenberg, V. I . , Katkova, N. V., Denisov, E . T., Cyclic chain termination by nitroxyl radicals in oxidizing ethylbenzene in the presence of alcohols and acids, Izv. Akad.Nauk SSSR, Ser. Khim., 287, 1988. Goldenberg, V. I . , Denisov, E . T., Ermakova, N. A., Acid-catalyzed cyclic chain termination by nitroxyl radicals in hydrogen peroxide containing oxidizing ethylbenzene, Izv. Akad.Nauk SSSR, Ser. Khim., 738, 1990. Goldenberg, V. I . , Ermakova, N. A., Denisov, E . T., Acid-catalyzed cyclic chain termination by quinonemonoanilide in oxidizing hydrocarbons, Izv. Akad. Nauk SSSR., Ser. Khim. 79, 1995. Denisov, E . T., Nonlinear correlations in reactions of alkyl radicals with C—H bonds of organic compounds, Kinet. Katal., 32, 461, 1991. Denisov, E . T., The parabolic transition state model and resultant nonlinear correlations for the kinetics of free radical reactions, Mendeleev Commun., 2, 1, 1992. Denisov, E . T., Denisova, T. G., Kinetic parameters of reaction R(V + RH on the principles of parabolic model of transition state, Kinet. Katal, 34, 199, 1993. Denisov, E . T., Drozdova, T. I . , Analysis of kinetic data of peroxyl radical reactions with phenols on the principals of parabolic model, Kinet. Katal, 35, 176, 1994. Denisov, E . T., Triplet repulsion and electron affinity as factors determining activation energy of free radical abstraction reaction, Kinet. Katal.,35, 325, 1994. Denisov, E . T., Main factors determining reactivity o f reagents in free radical abstraction reaction, Kinet. Katal., 35, 671, 1994.

Chapter 2 R A T E CONSTANTS O F E L E M E N T A R Y STEPS OF CHAIN OXIDATION O F HYDROCARBONS

Table 2.1 Enthalpies, activation energies and rate constants of reaction R 0 * + R H -> R O O H + R", E calculated by formulas 1.15-1.17,1.21. The values of A , br and a, see Table 1.6 2

e

Hydrocarbon

2

CH (CH ) CH

3

H0 '

CH (CH ) CH

3

CH (CH ) CH

3

3

2

3

2

3

2

3

3

3

(CH ) CHCH CH

3

(CH ) CHCH CH

3

3

3

2

2

2

2

1

k (333 K ) / lmol's" 1

*(400K)/ Imol's 1

0.21

8.0

jec-R0 *

37.8

62.2

0.11

4.5

ferf-R0 *

44.7

65.8

2.3 x 10"

H0 .

23.2

54.8

0.25

7.0

sec-ROi'

26.7

56.5

0.14

4.2

tert-ROi

33.6

60.0

3.8 x 10"

2

2

El k.1 mol

60.3

2

3

2

1

34.3

2

(CH ) CHCH CH 3

A/// kJmol"

R0 "

2

2

2

1.5

1.5

C(CH )

H0 ' 2

49.4

68.3

2.4 x 10

2

4

1.4

C(CH )

sec-ROi'

52.9

70.3

2

4

1.1 x 10~

0.8

C(CH )

tert-R0 '

59.8

74.1

3

4

2.8 x 10~

0.3

cyclo-CsHio

HO,'

26.4

56.4

1.42

4.3

cyc/o-CsHio

iec-R0 *

29.9

58.1

0.77

25.9

cyclo-CiUio

ferf-R0 "

36.8

61.6

0.22

9.0

cyclo-C }in

H0 '

30.6

58.5

0.80

27.5

cyclo-C Hn

iec-R0 "

34.1

60.2

0.44

16.5

cyclo-C^iin

tert-R0 '

41.0

63.8

0.18

5.6

cyclo-dUuCRi

H0 "

20.3

53.4

1.22

1.3 x 10

23.8

55.1

0.67

76.6 27.5

3

3

3

2

2

2

2

6

2

6

2

2

c>>cZo-C HuCH

sec-R0

cyclo-CiHuCB}

tert-R0

30.7

58.5

0.25

CH =CHCH

H0 '

-5.8

54.7

7.9 x 10"

6

2

3

3

2

2

2

19

2

2.2

2

20

Handbook of Antioxidants Hydrocarbon

R0 *

AH/ kJ mol '

2

El kJ mol

1

fc(333K)/ lmoi's

k (400 K ) / lmorV

1

CH =CHCH

3

sec-R0 '

-2.3

56.2

4.6 x 10"

CH =CHCH

3

tert-R0 '

4.6

59.3

1.5 x 10"

-18.0

49.5

1.0

21

2

-14.5

51.0

0.6

13

tert-R0

-7.6

53.9

0.2

27

H0 *

-16.4

50.2

0.8

17

-12.9

51.6

0.5

11

-6.0

54.6

0.2

2.0

-28.9

45.1

1.7

26

iec-R0 "

-24.7

46.8

0.9

15

tert-R0

-17.8

49.6

0.3

6.7

HOj"

-33.6

43.2

1.7

23

sec-R0 *

-30.1

44.6

1.0

15

tert-R0

-23.2

47.4

0.4

6.5

no

-20.8

48.3

1.6

30

-17.3

49.8

0.9

19

tert-R0 '

-10.4

52.7

0.3

7.9

-20.3

48.6

2.8

54

-16.8

50.1

1.6

34

-9.9

52.9

0.6

15

-30.8

44.3

45

6.6 x 10

2

2

2

2

c«-CH CH=CHCH 3

c;>CH,CH=CHCH

c/j-CH CH=CHCH 3

2

sec-R0

3

3

/ra»i-CH CH=CHCH 3

H0 '

3

2

3

2

/ran.s-CH CH=CHCH

3

rra«s-CH CH=CHCH

3

3

3

CH =CHCH CH

3

CH =CHCH CH

3

CH =CHCH CH

3

2

2

2

2

2

2

2

CH =CHCH(CH )

2

CH =CHCH(CH )

2

3

3

CH CH=C(CH )

2

CH CH=C(CH )

2

CH CH=C(CH )

2

3

3

3

3

3

3

2

2

2

2

tert-R0 ' 2

3

2

2

H0 "

CH =CHCH(CH ) 2

sec-R0

2

2

2

sec-R0

2

2

(CH ) C=C(CH )

2

H0 '

(CH ) C=C(CH )

2

sec-R0 *

(CH ) C=C(CH )

2

ter/-R0 *

3

3

3

2

3

2

3

2

3

2

2

2

1.4

2

2

0.5

cyclo-C$R%

H0 '

cyclo-dHa

sec-R0

2

-27.3

45.7

27

4.3 x 10

cyclo-CsHa

tert-R0

-20.4

48.5

10

1.9 x 10

cyclo-C H\o

H0

-31.7

44.0

50

7.2 x 10

cyclo-CiH%

sec-R0

2

-28.2

45.4

30

4.7 x 10

cyclo-CiHi

tert-R0

-21.3

48.1

11

2.1 x 10

Cyclopentadiene

R0

-71.8

29.4

5.0 x 10

Cyclopentadiene

sec-R0

-68.3

30.6

3.2 x 10

3

2

2.0 x 10"

Cyclopentadiene

tert-R0

-61.4

33.0

1.3 x 10

3

9.8 x 10

6

2

2

2

2

2

2

2.9 x 10

3

2

2

2

2

2

2

4

3

Ch. 2

Rate Constants for Chain Oxidation of Hydrocarbons

Hydrocarbon

R0 "

AH/ k.1 mol

2

1

El k J mol

21

1

k (333 K ) / lmoi's"

k (400 K ) / lmolV

1

1

1.3-Cyclohexadiene

H0 '

-63.6

32.2

3.5 x 10

3

2

2.5 x 10"

1,3-Cyclohexadiene

sec-ROi

-60.1

33.4

2.3 x 10

3

1.7 x 10"

1.3 -Cyclohexadiene

tert-ROi

-53.2

35.9

9.3 x 10

CeHjCHs

H0 '

-0.8

48.1

0.86

16

C6H5CH3

sec-ROi

2.7

49.7

0.48

9.7

CfiHsCHj

tert-ROi

9.6

52.8

0.16

3.8

2-CH3C6H5CH3

H0 "

1.9

49.3

1.11

22

2-CH3C6H5CH3

jec-R0 *

5.4

50.7

0.67

14

2-CH3C6H5CH3

tert-R0 "

12.3

53.9

0.21

5.5

4-CH C H4CH

H0 "

-3.6

46.8

2.74

46

sec-ROi'

-0.1

48.3

1.59

30

tert-ROi

6.8

51.4

0.52

12

3

2

6

4

4-CH C H CH 3

6

4

2

2

3

4-CH C«H CH 3

2

2

3

3

2

8.2 x 10

4-CH OC H CH

3

H0 *

-3.8

46.7

1.42

24

4-CH OC H CH

3

sec-ROi'

-0.3

48.2

0.83

15

4-CH OC H CH

3

tert-ROi

6.6

51.3

0.27

6.0

-1.9

47.5

1.06

19

1.6

49.0

0.62

12

8.5

52.2

0.19

4.6

-1.7

47.6

1.02

18

3

6

3

4

6

3

4

6

4

2

4-(CH ) CC H CH

3

H0 *

4-(CH ) CC H CH

3

iec-R0 "

4-(CH ) CC H CH

3

terf-R0 "

3

3

3

6

3

3

4

6

3

4

6

4

2

2

2

4-ClC H CH

3

H0 '

4-ClC H CH

3

sec-ROi

1.8

49.1

0.60

12

4-ClC,sH CH

tert-R0 '

8.7

52.2

0.19

4.6

UOi

-7.1

45.2

2.44

38

4-CNC6H4CH3

sec-ROi

-3.6

46.8

1.37

23

4-CNC H CH

tert-ROi

3.3

49.8

0.46

9.4

4-N02C6H4CH,

HOi

0.5

48.6

0.71

14

4-N0 C ri4CH

sec-ROi

4.0

50.1

0.42

8.6

4-N0 C H CH,

tert-ROi

10.9

53.3

0.13

3.3

C H CH CH

3

HOi

-12.0

43.1

3.47

47

C H CH CH

3

sec-ROi

-8.5

44.6

2.02

30

6

4

6

4

4

2

3

4-CNC H CH 6

4

6

2

2

6

6

5

3

4

6

(1

4

2

2

2

3

3

3

3

22

Handbook of Antioxidants Hydrocarbon

C H CH CH 6

5

2

R0 "

AHI kJmol"

2

ferf-R0 '

3

2

1

El kJmol"'

fc(333K)/ lmol's

1

A(400K)/ Imol's" 1

-1.6

47.6

0.68

12

-18.4

40.4

4.60

53

C H CH(CH )

2

C H CH(CH )

2

sec-R0 '

-14.9

41.9

2.68

34

C H CH(CH )

2

tert-R0 '

-8.0

44.8

0.94

14

-19.0

40.2

9.89

-15.5

41.7

5.75

72

-8.6

44.6

2.02

30

-24.8

37.8

11.81

-21.3

39.2

7.10

76 32

6

5

6

3

5

6

3

5

3

H0 " 2

2

2

no

(C H ) CH

2

(C H ) CH

2

sec-R0

(C H ) CH

2

tert-R0

6

5

6

5

6

5

2

2

2

2

2

2

1.1 x 10

2

(C H ) CHCH 2

3

H0 "

(C H ) CHCH 2

3

sec-R0

(C H,) CHCH

3

tert-R0

-14.4

42.1

2.50

CfiH5CH CH C6H5

H0 '

-12.8

42.8

7.74

C6H5CH CH CfiH5

sec-R0

-9.3

44.3

4.50

66

C6H5CH CH C6H5

tert-R0 '

-2.4

47.3

1.52

27

(C H ) CH

H0 *

-26.2

37.3

14.10

(C H ) CH

jec-R0 *

-22.7

38.7

8.51

88

(C H ) CH

ferf-R0 '

-15.8

41.5

3.10

38

H0 '

-26.4

37.2

29.2

2.8 x 10

2

5ec-R0 '

-22.9

38.6

17.6

1.8 x 10

2

terf-R0 '

-16.0

41.4

Indane

H0 '

-14.2

42.4

48.0

6.2 x 10

2

Indane

sec-R0

-10.7

43.7

27.9

3.9 x 10

2

Indane

tert-R0

-3.8

46.7

9.5

1.6 x 10

2

Tetraline

uo

-20.0

39.7

2.4 x 10

2

2.6 x 10

3

Tetraline

sec-R0

-16.5

41.2

1.4 x 10

2

1.7 x 10

3

Tetraline

tert-R0

-9.6

44.1

7.0 x 10

2

6

5

6

5

6

2

2

6

5

6

3

2

2

2

5

2

2

2

6

2

2

3

2

2

2

2

3

2

3

2

2

C H CH CH=CH 6

5

2

2

C6H5CH CH CH

2

=

2

2

2

2

2

2

2

2

2

1.2 x 10

1.0 x 10

1.3 x 10

6.41

48.4

2

2

2

78.5

Ch. 2

Rate Constants for Chain Oxidation of Hydrocarbons

23

Table 2.2 Rate constants of isomerization and monomolecular decomposition of peroxyl radicals R-c/o-[C(C H5)=CH(CH )4)]

c>'c/o-[C(0 ")(C H )C*H(CH )4

343

6.6 x 10

2

23

^c/o-[C(C H )=CH(CH ) ]

cyc/o-[C(0 )(C H )C H(CH )

333

4.9 x 10

2

4

23

cyc/o-[C(C H )=CH(CH )4]

cycto-[C(0 "XC H )C*H(CH )4

323

2.8 x 10

2

23

CH =CHCN

~CH CH(0 ')CN

323

CH =CHCN

~CH CH(0 ')CN

303

CH =CHCN

~CH CH(0 ')C H

CH =CHCN

H0 *

CH =CHCN

(CH ) C0 -

CH =CHCN

C H (CH ) C0

CH CH=CHCN

6

5

2

(i

6

2

3

6

2

5

2

2

4

2

6

5

2

5

2

2

2

2

2

2

,

6

2

2

2

!

,

2

2

2

6

2

6

5

2

2

15

3.25

20

323

24.5

15

323

35.0

15

0.70

15

323

1.5

15

~CH(CH )CH(CN)0 '

303

4.5

20

6

3

10.8

323

3

2

8.15-35.1/8

3

2

5

3

2

2

3

2

CH =CHOC(0)CH

3

C H (CH ) C0 *

323

0.20

15

CH =CHOC(0)CH

3

(CH ) C0 *

323

0.10

15

CH =CHOC(0)CH

3

H0 *

323

6.8

15

2

2

2

CH =CHOCH CH 2

2

6

3

3

3

3

2

2

2

2

3

2

20

2

20

(CH ) C0 *

303

4.0 x 10" 1.3 x 10"

3

3

2

CH CH C(0)CH=CH

2

(CH ) C0 '

303

(CH ) C=CHC(0)CH

3

H0 *

323

8.7

15

CH =CHC(0)CH CH

3

~CH CH(C(0)CH CH )0 '

303

2.7

20

C H (CH ) C0 '

323

0.50

15

3

2

3

2

2

2

CH =CHC(0)0CH 2

3

3

3

2

2

2

6

3

2

3

2

2

3

2

26

Handbook of Antioxidants

Oxidizing compound

77 K

Peroxyl radical

kI 1 mol s or logfe= A-E/Q 1

323

0.40

15

323

9.8

15

3

323

1.7

15

~CH CH(0 ')OC(0)CH

3

323

3.4

15

~CH CH(0 ')0C(0)CH

3

323

2.8

15

CH =CHC(0)OCH

3

(CH ) C0 *

CH =CHC(0)0CH

3

~CH CH(0 ')C H

CH =CHC(0)OCH

3

~CH CH(0 ')C(0)OCH 2

CH =CHC(0)OCH

3

2

2

2

2

3

2

3

2

2

2

2

2

CH =CHOC(0)CH ) 3

Ref.

1

6

5

2

2

2

CH =C(CH )C(0)OCH

3

C H (CH ) C0 -

323

1.8

15

CH =C(CH )C(0)OCH

3

(CH ) C0 '

323

1.1

15

CH =C(CH )C(0)OCH

3

H0 "

323

40

15

CH =C(CH )C(0)OCH

3

~CH CH(0 *)C H

323

12

15

CH =C(CH )C(0)OCH

3

~CH C(CH )(0 ')C(0)CH

(CH ) C=CHOC(0)CH

3

(CH ) C0 "

(CH ) C=CHC(0)0CH

3

2

3

2

3

2

3

2

3

2

3

3

2

3

2

6

2

3

2

2

2

2

2

2

3

2

303-323

3

2

3

3

2

20

0.20

H0 "

323

13.1

15

H0 *

323

14.2

15

H0 *

323

1.4

15

H0 '

323

0.60

15

3

2

2

CH CH OC(0)CH=CHC(0)OCH

24

303

2

2

cis-

8.92-53.5/8

~C(CH ) CH(C(0)OCH )0 '

2

2

rra»i-CH CH=CHC(0)OCH CH 3

5

1.0 x 10"

3

3

3

6

303

3

3

2

20

2

3

trans-

2

CH CH OC(0)CH=CHC(0)OCH 3

CH

3

3

fra«s-CH CH=CHC(0)0CH

CH

5

2

2

3

CH =C(CH )C(0)0(CH ) CH 2

3

2

3

~CH C(0 ')(CH )C(0)(CH ) CH

3

2

2

3

2

3

303-323

3

7.80-45.6/0

24

323

1.4

24

~CH C(CH )(C(0)OCH CH(CH ) 0 "

323

2.4

24

C H (CH ) C0 -

323

0.76

25

C H (CH ) C0 "

323

1.28

25

[CH =C(CH )C(0)OCH ] C

C H (CH ) C0 '

323

3.08

25

CH =CHC(0)NH

2

C H (CH ) C0 "

323

0.40

15

CH =CHC(0)NH

2

(CH ) C0 -

323

0.20

15

(CH ) C0 -

323

0.30

15

CH =CHC(0)0(CH ) CH 2

2

3

~CH CH(C(0)0(CH ) CH )0 *

3

2

CH =C(CH )C(0)0CH CH(CH ) 2

3

2

3

[(CH =CHC(0)0CH ] C(CH ) 2

2

2

3

[CH =CHC(0)0CH ] C 2

2

2

4

3

2

2

2

3

2

6

6

2

CH =C(CH )C(0)NH

2

2

4

6

6

3

5

3

5

2

3

5

2

3

5

3

3

2

2

3

3

3

2

2

3

2

2

2

2

2

3

2

2

2

3

2

2

Ch. 2

Rate Constants for Chain Oxidation of Hydrocarbons

27

Table 2.4 Rate constants of addition of alkyl radicals to molecular oxygen 77 K

R"

C"H

3

CH C'H 3

2

CH C"H(CH ) CH 3

2

7

3

Solvent

*/ lmol's

Ref. 1

296

H 0

4.7 x 10

9

26

298

RH

2.9 x 10

9

27

298

RH

4.8 x 10

9

28

2

CH (CH )i C'HCH

298

RH

1.5 x 10

9

3

29

CH (CH ), C'HCH

298

RH

1.5 x 10

9

3

29

CH (CH ) CH=CHC"HCH=CH(CH ) COOH

295

RH

3.0 x 10

s

30

CH CH (CH=CHCH ) CH=CHC'H(CH ),iC(0)OH

295

RH

3.0 x 10

s

30

cyc/o-[CH=CHC HCH=CHCH ]

300

RH

1.6 x 10'

31

cyc/o-[CH(OH)C[C(CH ) ]=CHC'(CH )CH=C(C(CH ) ]

298

RH

9.0 x 10

7

29

HOCH=CH'

295

RH

1.0 x 10

9

32

C6H5C*H

294

RH

2.0 x 10

9

33

323

RH

8.8 x 10

8

34

C H (CH ) C*

323

RH

9.0 x 10

s

31

(C H ) C'H

294

RH

7.5 x 10

s

33

(C H ) C

293

RH

1.2 x 10

9

35

323

RH

8.0 x 10

7

34

294

RH

9.0 x 10

s

33

300

RH

4.9 x 10

9

31

3

2

3

3

2

3

4

2

3

4

2

2

2

7

2

2

,

2

3

2

CeHsC H C H 6

5

6

3

5

6

3

2

2

5

3

RCH C HC H ,

2

6

5

4-N0 C H C'H 2

6

4

2

(C H ) NC'HCH 6

5

2

3

3

3

3

3

Table 2.5 Rate constants of recombination and disproportionation of peroxyl radical in hydrocarbon solutions 77 K

Peroxyl radical ^

210-300

(CH ) CH0 * 3

2

2

303

CH (CH ) CH 0 ' 3

2

2

2

2

CH CH CH(0 *)CH 3

2

2

3

193-257

kl l m o l ' s " or \ozk = A-Em 1

7.89 - 10.34/0 4 x 10

7

9.0-11.3/0

Ref.

36 37 38

28

Handbook of Antioxidants 77 K

Peroxyl radical

(CH ) CCV 3

3

CH CH(0 -)(CH ) CH 3

2

2

2

3

CH (CH ) C(0 -)(CH3) 3

2

2

2

2

kl I mol s" or iozk = A-EIQ -1

1

Ref.

193-257

9 . 3 - 31.8/0

38

233-310

8 . 5 - 10.9/8

67

213-273

11.1 - 39/0

40

CH CH(0 ')(CH ) CH

3

283-320

7 . 4 6 - 8.4/0

41

CH CH(0 ')(CH ) CH

3

294-324

7 . 4 6 - 8.4/0

41

3

2

3

2

2

3

2

4

(CH ) CC(0 ')(CH ) 3

3

2

3

243-293

2

9 . 2 - 31.4/0

40

CH CH(0 ')(CH ) CH

3

283-356

7 . 4 6 - 8.4/0

41

CH CH(0 *)(CH ) CH

3

283-324

7 . 4 6 - 8.4/8

41

CH CH(0 ")(CH ) CH

3

283-355

7 . 4 6 - 8.4/0

41

CH CH(0 ')(CH ) CH

3

284-355

7 . 4 6 - 8.4/0

41

243-293

13.41 - 46/0

42

293-358

7 . 4 6 - 8.4/0

41

3

2

3

2

2

3

2

2

3

5

6

2

2

7

2

9

(CH ) C(0 ')CH CH(CH )CH CH(CH )CH(CH ) 3

2

2

2

3

CH CH(O ')(CH ) CH 3

2

2

10

2

3

3

2

3

175-200

e>-c/o-[CH(0 'XCH )5]

285-333

7 . 2 9 - 5.4/8

41

cyc/o-[CH(0 *XCH ) ]

298

8.6 x 10*

44

cycto-[CH(0 'XCH ) ]

298

1.4 x 10

44

cyc/o-[CH(0 ')(CH )„]

345-417

8 . 1 2 - 7.8/0

2

2

4

2

2

2

2

2

6

2

2

7

2

CH =CHCH(0 *)CH=CH 2

2

(CH ) C=CHCH(0 *)CH 3

2

2

303

2

CH CH CH=CHCH(0 *)CH CH 3

2

2

2

3

ciJ-CH (CH ) CH=CHCH(0 *)CH CH 3

2

2

2

C H CH=CHCH 0 6

5

2

3

2

CH =CHCH(0 "XCH ) CH 2

2

2

2

4

3

(CH ) C=CHC(0 'XCH )CH CH(CH )CH(CH ) 3

2

2

3

2

3

3

2

CH CH CH=CHCH(0 ')CH=CHCH CH=CHCH C(0)OCH 3

2

2

2

2

CHj(CH ) (CH=CH) CH(0 *)(CH ) C(0)OCH 2

4

2

2

2

7

CH (CH ),CH=CHCH(0 "XCH ) C(0)OCH 3

2

2

2

6

3

3

CH (CH ) CH=CHCH(0 ')CH=CH(CH ) C(0)OCH CH 3

2

4

2

2

cyc/o-[CH(0 ')CH=CH(CH ) ] 2

2

2

7

2

3

3

1.1

X

7

10

9

46 68

7 . 4 - 5.0/0

47

303

6.4 x 10

6

37

323

1.5 x 10

7

48

303

4.4 x 10

s

49

298

1.0 x 10

7

50

234-293

1 0 . 2 - 21/8

42

353

1.8 x 10

51

303

2.43 x 10

6

52

303

1.06 x 10

6

22

298

3.0 x 10

7

53

313-333

3

9 . 6 - 10.9/8

43

cyc/o-[CH(0 ')(CH ) ]

193-257

7

7 . 8 - 4.2/6

38

Ch. 2

Rate Constants for Chain Oxidation of Hydrocarbons

29

Peroxyl radical

77 K

fc/lmor's" or \ozk = A-E/9

QH CH [CH(CH ) ] -C H C(-c/o-[CH(0 ')(CH ) ]-C H4

333

R,H/R H

1.2 x 10

7

69

cyc/o-[CH=CHCH(0 ")(CH ) ]

c>c/o-[OCH(0 ')(CH ) ]

333

R,H/R H

1.1

10

7

76

cyc/o-[CH=CHCH(0 ')(CH ) ]

CH (CH ) CH(0 ')0(CH ) CH

333

R,H / R H

8.2 x 10

6

76

C H C(OH)(CH )0 '

cyc/o-[C(OHX0 *XCH ) ]

333

R,H/R H

2.5 x 10

6

73

~CH CH(C H )0

~CH CH(CN)0 *

323

R,H / R H

4.8 x 10

7

2

77

~CH CH(C H )0

323

RiH / R H

2.5 x 10

6

2

77

323

R,H / R H

1.5 x 10

6

77

323

R,H / R H

2.7 x 10

5

77

323

RiH / R H

6.9 x 10

4

77

2

2

2

2

2

3

3

2

6

2

6

3

5

2

5

3

2

2

2

3

3

2

3

2

3

2

2

-

3

2

2

2

2

2

2

3

2

~CH CH(0 ")C(0)OCH 2

2

2

3

~CH C(CH )(0 ')(0)OCH

~CH C(CH )(C H,)0 "

~CH CH(0 *XO)OCH

2

3

3

6

6

3

3

~CH C(CH )(C H )0 ' 2

ara-disubstituted diphenylaminyl radicals with phenols in decane estimated by laser photolysis technique ' 14

~ .

Phenol

ft(294

para-Substituents

15

K ) / 1 mol s" 1

1

H, H

Br, Br

CH , CH 3

3

CH 0, H 3

9

4-CH C H OH

7.0 x 10'

9.6 x 10'

3.2 x 10

6

2.2 x 10

6

26

4-HOC H OH

1.3 x 10

7

1.0 x 10

7

2.8 x 10

6

2.0 x 10

6

36

C H OH

9.8 x 10

5

7.0 x 10

5

6.5 x 10

s

3.6 x 10

5

51

2,6-((CH ) C) -C H OH

7.3 x 10

6

6.4 x 10

6

5.2 x 10

6

3.4 x 10

6

52

2,4,6-((CH ) C)3-C H OH

1.3 x 10

7

7.9 x 10

6

1.1 x 10

7

7.9 x 10

6

53

2,6-((CH ) C) -4-CH CO-C H OH

1.0 x 10

7

3.4 x 10

6

6.4 x 10

6

5.8 x 10

6

55

2,6-((CH ) C) -4-((CH ) CO)-C H OH

3.5 x 10

7

2.0 x 10

7

2.9 x 10

7

2.6 x 10

7

58

2,6-((CH ) C) -4-Cl-C H OH

1.4 x 10

7

9.1 x 10

6

1.1 x 10

7

7.3 x 10

6

60

2,6-((CH ) C) -4-CN-C H OH

1.1 x 10

7

3.3 x 10'

1.2 x 10

7

9.8 x 10

6

61

2,6-((CH ) C) -4-CHO-C H OH

1.3 x 10

7

4.3 x 10

6

1.1 x 10

7

9.4 x 10

6

64

2,6-((CH ) C) -4-CH -C H OH

1.2 x 10

7

7.9 x 10

6

1.1 x 10

7

7.5 x 10

6

78

4-CH OC H OH

1.5 x 10

8

1.6 x 10

8

5.9 x 10

7

2.6 x 10

7

83

2,6-(CH ) C H OH

2.1 x 10

7

1.8 x 10

7

9.0 x 10

6

5.1 x 10

6

2,4,6-(CH ) C H OH

5.0 x 10

7

4.2 x 10

7

3.1 x 10

7

2.1 x 10

7

4-ClC H OH

2.9 x 10

6

3.8 x 10

6

1.1 x 10

6

5.6 x 10

5

2.9 x 10

7

3.0 x 10

7

1.7 x 10

7

1.3 x 10

7

2.6 x 10

s

2.5 x 10

8

2.3 x 10

s

1.6 x 10

8

2,6-((CH ) C) -4-(CH ) NCH -C H OH

1.4 x 10

7

7.8 x 10

6

8.4 x 10

7

7.0 x 10

6

2,6-((CH ) C) -4-Br-C H OH

1.6 x 10

8.7 x 10

7

9.0 x 10

6

7.8 x 10

6

110

3

6

4

6

6

4

5

3

3

2

3

3

3

3

3

6

6

2

2

6

2

6

2

2

3

6

2

2

4

2

6

3

6

6

2

6

3

3

2

3

3

2

2

3

3

6

2

3

3

3

2

3

3

3

3

3

3

6

3

3

6

2

4

2,6-(CH 0) C H OH 3

2

6

3

2,5-((CH ) C) -4-HOC H OH 3

3

3

3

3

3

2

2

2

6

3

2

2

6

2

2

6

2

7

96

Handbook of Antioxidants Table 4.8 Enthalpies, activation energies and rate constants of reaction between diphenylaminyl radical and aromatic amines calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 e

No.

Amine

El k l mol'

£(333 K ) / linol" s

fc(400K)/ Imol's"

-4.5

11.6

1.5 x 10

6

3.1 x 10

6

0.0

13.8

6.8 x 10

5

1.6 x 10

6

-0.5

13.6

7.4 x 10

5

1.7 x 10

6

-16.1

6.2

1.1 x 10

7

1.6 x 10

7

-7.2

10.3

2.4 x 10

6

4.5 x 10

6

AHI kl mol

1

1

1

1

135

(2-C H )2NH

136

(C H ) NH

137

(4-BrC rL,)2NH

138

(4-CH OC H ) NH

139

(4-CHjC H ) NH

140

(4-(CH ) CC H4) NH

-5.9

10.9

1.9 x 10

6

3.8 x 10

6

141

4-CH OC H4NHC H

-8.8

9.6

3.1 x 10

6

5.6 x 10

6

142

4-N0 C H NHC H

8.2

18.0

1.5 x 10

5

4.5 x 10

5

143

4-(CH ) CC H NHC H

-4.4

11.6

1.5 x 10

6

3.1 x 10

6

144

1-C H,NH

10.0

19.0

1.0 x 10

5

3.3 x 10

5

2

145

2-C H NH

14.8

21.6

4.1 x 10

4

1.5 x 10

5

2

146

2-C H NHC H NH-2'-C H

-18.1

5.4

1.4 x 10

7

2.0 x 10

7

147

4-C H NHC H NHC H

-17.8

5.5

1.4 x 10

7

1.9 x 10

7

148

4-C H NHC H NHC H

-8.8

9.6

3.1 x 10

6

5.6 x 10

6

149

4-(CH ) CHC H NH-4-C H NHC H CH(CH )

-31.3

0.0

1.0 x 10

s

1.0 x 10

s

150

4-C H NHC«H NHCH(CH )

-15.5

6.5

9.6 x 10

6

1.4 x 10

7

151

C H N H - 1 -3,7-[(CH ) C] C H

-19.8

4.6

1.9 x 10

7

2.5 x 10

7

152

1-C, H NHC H

-7.6

10.1

2.6 x 10

6

4.8 x 10

6

153

2-CioH NHC H

-1.8

12.9

9.5 x 10

5

2.1 x 10

6

154

2-CioH NH(4'-C H 0)C H

-15.2

6.6

9.2 x 10

6

1.4 x 10

7

155

l,2-cyc/o-[C(cyc/o-CH CH 0)CH C(NH-(eyc/o-C Hii))]C H4

5.1

16.4

2.7 x 10

5

7.2 x 10

5

156

l-[NHC H -4'-C(CH ) ]-4-(CH ) CCioH

-12.6

7.8

6.0 x 10

6

9.6 x 10

4

157

l,2-cycto-[C(CH )CH C(CH ) NH]C H

-3.8

15.7

3.4 x 10

5

8.9 x 10

5

1 0

6

7

5

2

6

3

6

6

3

4

3

3

6

3

2

6

2

6

4

10

6

7

10

(i

3

10

7

8

6

10

4

8

4

2

6

6

5

n

6

4

4

3

3

7

6

7

6

7

3

2

6

4

3

3

2

10

5

5

5

6

5

6

2

6

7

5

4

5

0

5

4

6

3

6

6

6

5

5

4

4

1 7

6

2

6

2

6

4

4

3

3

4

2

2

3

2

3

3

2

6

3

6

4

6

6

Ch. 4

Reactions of Aromatic Amines

97

Table 4.9 Rate constants of reaction of aromatic amines with oxygen: AmH + 0 -> Am* + H 0 * calculated by formula 1.17 with A = 3 x 10 1 mol" s" per one N-^I-bond and E = AH 2

2

10

No.

1

1

Amine

El k J mol"

1

ft(400 K ) / 1 mol" s"

ft(500 K ) / lmolV

1

1

1

135

(2-C H ) NH

156.8

1.0 x 10"'°

1.2 x 10"

136

(C«iH ) NH

161.3

2.6 x 10""

4.2 x 10"

2

137

(4-BrC H4) NH

160.8

3.0 x 10"'

4.8 x 10"

7

138

(4-CH OC H ) NH

145.2

3.3 x 10"'

2.0 x 10"

5

139

(4-CH C H ) NH

154.1

2.3 x 10"'°

2.4 x 10"

6

140

(4-(CH ) CC H ) NH

155.4

1.5 x 10"'°

5.8 x 10"

7

141

4 - 0 ^ 0 0 6 ^ ^ ^

152.5

3.7 x l O "

3.5 x 10"

6

142

4-N0 C H NHC6H

169.5

2.2 x 10"

12

5.9 x 10"

8

143

4-(CH ) CC6H NHC H

156.9

9.7 x 10"

11

1.2 x 10"

6

144

l-C,oH,NH

171.3

2.6 x 10"

12

7.6 x 10"

8

2

145

2-C H,NH

176.1

6.1xl0"

1 3

2.4 x 10"

8

2

146

2-C H NHC6H NH-2'-CioH

143.2

1.2 x 1 0

s

6.6 x 10"

5

147

4-C Hi NHC H4NHC H

143.5

1.1 x 10"

6.1 x 10"

5

148

4-C6H5NHC6H4NHC6H5

152.5

7.3 x 10"

7.0 x 10"

6

149

4-(CH ) CHC6H NH-4-C H NHC H CH(CH )

130.2

6.0 x 10"

7

1.5 x 10"

150

4-C H NHC6H NHCH(CH )

145.8

5.5 x 10"'

3.5 x 10"

5

151

C6H NH-l-3,7-[(CH ) C] C H3

141.5

1.0 x 10"

10

5.0 x 10"

3

152

1-C H NHC6H

153.7

2.5 x 10"

10

2.6 x 10"

6

153

2-CioH NHC6H

159.5

4.5 x 10"

11

6.5 x 10"

7

154

2-C H NH(4'-C6H O)C H

146.1

2.5 x 10"

9

1.6 x 10"

3

155

l^-cyc/o-fCCcyc/o-CHjCH^CHjCCNH-Ccycto-CsHn^CsH,

166.4

5.6 x 10"

1.2 x 10"

7

156

l-[NHC6H -4'-C(CH ) ]-4-(CH ) CC H6

148.7

1.1 x 10"'

8.8 x 10"

6

157

l^-cyc/o-ICCCH^CHjCCCH^NHlCsrl,

165.1

8.3 x 10"

1.7 x 10"

7

10

7

5

2

2

6

2

3

6

3

6

3

2

6

3

4

4

3

2

6

3

4

6

3

8

6

2

6

3

3

7

7

10

4

4

5

7

3

2

6

4

3

3

2

10

5

5

5

4

7

17

4

3

10

5

4

7

6

2

4

7

8

4

4

10

10

2

6

3

3

4

3

3

10

1

1 0

8

10

12

12

6

3

98

Handbook of Antioxidants Table 4.10 The values of nonstoichiometric coefficients of chain termination by aromatic amines in oxidizing substances R H with cyclic chain termination

No.

Amine

RH

R0 "

T/K

136

(C H ) NH

1,3-Cyclohexadiene

H0 *

348

200

17

136

(C H ) NH

C H CH=CHCOOC H

H0 "

323

20

18

136

(C H ) NH

C H CH=CHCOOCH

H0 "

323

20

18

136

(C H ) NH

C H CH=CHCOOC H

H0 "

323

20

18

136

(C H ) NH

cyclo-CttuOH

R0 "

393

56

19

136

(C H ) NH

(CH ) N(CH ) OCO(CH )C=CH

R0 *

323

10

20

138

(4-CH OC H ) NH

(CH ) NCH CH N(CH )

R0 *

313

26

21

138

(4-CH OC H ) NH

(CH ) CHOH

R0 "

343

22

22

138

(4-CH OC H ) NH

cyclo- [N(CH )(CH ) ]

R0 '

323

52

23

138

(4-CH OC H ) NH

N(CH CH )

R0 "

313

80

23

138

(4-CH OC H ) NH

cyc/o-C H„N(CH )

2

R'c/o-[C(CH )=CHC(CH )2N(OH)]

-69.1

0.0

3.2 x 10'

201

C,Hi [(CH ) C]NOH

-23.9

14.6

1.6 x 10

s

202

C«H C(0)[(CH ) C]NOH

-35.6

9.7

9.6 x 10

s

207

[(CH ) C] C=NOH

-20.1

16.3

8.9 x 10

4

208

(CF ) NOH

-12.9

19.5

2.8 x 10

4

209

(CH ) CHN(OH)C(CH )

-5.9

22.9

8.2 x 10

3

211

(CH )2CHCH C(0)N(OH)C(CH )

-42.1

7.1

2.5 x 10

6

212

4-N0 C H4N(OH)C(CH )

-23.0

15.0

1.4 x 10

3

213

C H CH=CHC(0)N(OH)C(CH )j

-37.2

9.1

1.2 x 10

214

4-C H C H4C{0)N(OH)C{CHj)

-34.2

10.3

7.8 x 10

s

215

C H CH CH2C(0)N(OH)C(CH )

-40.0

8.0

1.8 x 10

s

216

CH (CH ),C(0)N(OH)C(CH )

-41.4

7.4

2.2 x 10

6

217

cyc/o-[C(CH )2(CH ) C(CH )2N(OH)]

-67.4

0.0

3.2 x 10

218

cyc/o-[C(CH )2CH2CH(OC(0)C H )CH C(CH )2N(OH)] 3

-58.3

1.3

2.0 x 10

219

cyc/o-[C(CH )2CHBrC(0)CH2C(CH ) N(OH)]

-55.2

2.3

1.4 x 10

220

cyc/o-[C(CH )2CHClC(0)CH2C(CH )2N(OH)]

-60.9

0.4

2.8 x 10

221

cyc/o-ICXCHj^CH^HCOHJCHACHj^OH)]

-56.4

1.9

1.6 x 10'

222

cyc'o-[C(CH )2CH C(0)CH C(CH )2N(OH)]

-58.2

1.3

2.0 x 10

223

cyc/o-tqCft^CHCC^N^JCHjCCCHs^OH)]

-67.6

0.0

3.2 x 10'

224

cyc/o-[C(CH )2CH(C(0)OH)CH C(CH ) N(OH)]

-68.5

0.0

3.2 x 10

225

cyc/o-ICCCHj^CHCOH^HjCCCHs^NCOH)]

-69.5

0.0

3.2 x 10

226

cvc/o-fCCCHs^COCHjCCCHjJjNCOH)]

-59.9

0.7

2.5 x 10

227

cyc/o-[C(CH ) C(0)N(OH)C(CH ) N(OH)]

-52.6

3.3

9.7 x 10*

232

cyc/o-ICCCHj^NCOJ^CHsJCHACHj^OH)]

-49.8

4.3

6.8 x 10

6

235

cyc/o-[C(CH ) CH C(C H5)=CHC(CH ) N(OH)]

-62.7

0.0

3.2 x 10

7

237

l,2-C«H [C(C«H ) ]-cyc/o-[C(CH XC«H5)CHjC(CH )2N(OH)]

-65.8

0.0

3.2 x 10

7

3

2

3

3

3

s

3

5

3

3

3

3

3

3

3

3

2

2

3

3

2

3

2

3

6

3

6

3

3

3

3

3

6

3

2

3

6

3

3

5

3

2

3

5

6

3

3

2

2

3

2

3

3

3

3

3

6

3

3

2

3

3

3

3

2

3

2

3

3

3

2

3

3

2

2

3

2

2

5

3

>c/o-[C(CH ) C(C H )=N(0)C(CH )(N(CH )OH)N(OH)]

-13.0

13.4

2.5

x

10

5

5.7

x

10

5

200

l^-CsHjtCCCsHj^l-cycZo-tCCCHj^CHCCCHj^NCOH)]

-33.5

4.6

6.1

x

10

6

8.0

x

10

6

201

C H [(CH ) C]NOH

11.7

25.7

3.0

x

10

3

1.5

x

10

4

202

C H C(0)[(CH ) C]NOH

0.0

19.6

2.7

x

10

4

8.8

x

10

4

207

[(CH ) C] C=NOH

15.5

27.7

1.4

x

10

4

7.7

x

10

3

208

(CF ) NOH

22.7

31.7

3.4

x

10

2

2.3

x

10

3

209

(CH ) CHN(OH)C(CH )

29.7

35.8

6.8

x

10

2

211

(CH ) CHCH C(0)N(OH)C(CH )

-6.5

16.4

8.6

x

10

4

2.3

x

10

3

213

C H CH=CHC(0)N(OH)C(CH )

-1.6

18.8

3.6

x

10

4

1.1

X

10

3

214

4-C«H C H C(0)N(OH)C(CH )

1.4

20.3

2.1

x

10

4

7.1

x

10

4

215

C H CH CH C(0)N(OH)C(CH )

-4.4

17.4

6.0

x

10

4

1.7

x

10

3

217

cyc/o-[C(CH ) (CH ) C(CH ) N(OH)]

-31.8

5.3

4.7

x

10

7

6.5

x

10

6

218

cyc/o-[C(CH ) CH CH(OCOC H )CH C(CH ) N(OH)]

-22.7

9.1

1.2

x

10

6

2.1

x

10

6

219

cycto-[C(CH ) CHBrC(0)CH C(CH ) N(OH)]

-19.6

10.5

7.2

x

10

5

1.4

x

10

6

220

cyc/o-[C(CH ) CHClC(0)CH C(CH ) N(OH)]

-15.1

12.5

3.5

x

10

5

7.5

x

10

7

221

cyc/o-[C(CH ) CH CH(OH)CH C(CH ) N(OH)]

-20.8

9.9

9.0

x

10

s

1.6

x

10

6

222

c>'c/o-[C(CH ) CH C(0)CH C(CH ) N(OH)]

-22.6

9.1

1.2

x

10

6

2.1

x

10

6

227

cyc/o-[C(CH ) C(0)N(OH)C(CH ) N(OH)]

-17.0

11.6

4.8

x

10

3

9.8

x

10

3

232

cycto-[C(CH ) N(0)=C(CH )CH C(CH ) N(OH)]

-14.2

12.8

3.1

x

10

3

6.8

x

10

3

235

cycto-[C(CH ) CH C(C«H )=CHC(CH ) N(OH)]

-27.1

7.2

2.4

x

10"

3.7

x

10*

237

1,2-C'c/o-[C(CH XC6H )CH C(CH ) N(OH)]

-65.0

0.0

1.0 x 10

8

1.0 x 10

8

2

2

2

3

3

6

2

3

3

3

2

3

3

3

3

2

3

2

2

3

2

3

3

2

3

2

3

5

3

3

6

5

3

2

6

6

3

3

3

3

2

3

3

3

2

2

3

3

3

3

13

6

2

2

3

6

3

2

3

2

3

2

2

2

6

3

6

3

2

2

3

3

2

3

2

2

5

3

6

2

3

2

2

3

3

3

2

3

3

3

3

3

3

3

2

2

2

5

3

3

3

2

2

2

3

2

3

2

7

88

7

7

3.4 x 10

7

1.0 x 10"

Ch. 5 No.

Reactions of Hydroxylamines and Nitroxyl Radicals Hydroxylamine

115

AHI k J moP

1

El k J mol

-1

*(333K)/ 1 m o l s~

*(400K)/ I mol ' s

-1

l

-

_1

4-(CH ) COC H 0' 3

3

6

4

158

cyc/o-[CH(NOHXCH ) -CH(CH ) ]

-27.0

9.3

3.4

x

10

6

6.2

x

10

6

159

cyc/o[CH(NOHXCH ) .CH(CH ) ]

-23.6

10.8

2.0

x

10

6

3.8

x

10

6

172

cycto-[C(CH ) C(CH ) N=C(C H )N(OH)]

-33.6

6.6

9.4

x

10

6

1.4

x

10

7

173

cyc/o-[C(CH ) C(C H )=N(0)C(CH )(N(CH pH)N(OH)]

-35.8

5.8

1.2

x

10

7

1.8

x

10

7

200

l,2-C H [C(C H ) ]-cvc/o-[C(CH )=CHC(CH ) N(OH)]

-56.3

0.0

1.0

x

10

8

1.0

x

10"

201

C H [(CH ) C]NOH

-11.1

16.4

2.7

x

10

5

7.2

x

10

5

202

C H C(0)[(CH ) C]NOH

-22.8

11.1

1.8

x

10

6

3.4

x

10

6

207

[(CH ) C] C=NOH

-7.3

18.2

1.4

x

10

5

4.1

x

10

3

208

(CF ) NOH

-0.1

21.7

4.1

x

10

4

1.5

x

10

3

209

(CH ) CHN(OH)C(CH )

6.9

25.3

1.1 X 10

4

5.0

x

10

4

211

(CH ) CHCH C(0)N(OH)C(CH )

-29.3

8.4

4.7

x

10

6

8.1

x

10

6

213

C H CH=CHC(0)N(OH)C(CH )3

-24.4

10.4

1.5

x

10

6

4.4

x

10

6

214

4-C«H C H4C(0)N(OH)C(CH )

-21.4

11.7

1.5

x

10

6

3

2.7

x

10

215

CsHjCH^H^OJNCOH^C^^

-27.2

9.3

3.4

x

10

6

6.2

x

10

6

217

cydo-[C(CH ) (CH ) C(CH ) N(OH)]

-54.3

0.0

1.0

x

10

8

1.0

x

10

8

218

cyc/o-tCCCHj^CH^HCOCOCtHsJCH^CCHj^NCOH)]

-45.5

2.0

4.9

x

10

7

5.5

x

10

7

220

cyc/ofCCCft^CHClCCOJCHj^Cft^NCOH)]

-37.9

4.9

1.7

x

10

7

2.3

x

10

7

221

cydo-ICCCHj^CHjCHCOHJCHACHj^NCOH)]

-43.6

2.8

3.8

x

10

7

4.4

x

10

7

222

cydo-tCCCHj^CH^COJCHACHj^NCOH)]

-45.4

2.1

4.7

x

10

7

5.3

x

10

7

227

cyc/o-[C(CH ) C(0)N(OH)C(CH ) N(OH)]

-39.8

4.2

2.2

x

10

7

2.8

x

10

7

232

cycto-[C(CH )jN(0)=C(CH )CH C(CH ) N(OH)]

-37.0

5.3

1.5

x

10

7

2.0

x

10

7

235

cyc/o-fCCCHj^CH^CeHs^CHCXCHj^NCOH)]

-49.9

0.5

8.4

x

10

7

1.0

x

10

8

237

l,2-C H [C(C H )3]-C)'c/o-[C(CH XC6H )CH C(CH ) N(OH)]

-53.0

0.0

1.0

x

10

8

1.0

x

10

8

2

3

2

3

2

3

6

8

6

2

6

13

3

3

2

2

2

6

3

3

3

5

3

3

3

3

3

2

3

3

3

6

s

5

3

3

2

2

3

2

3

6

3

3

2

3

2

3

2

3

3

3

5

5

6

3

3

2

3

2

3

6

3

2

2

3

3

6

3

3

5

2

2

3

3

2

5

2

3

2

fi

116 No.

Handbook of Antioxidants Hydroxylamine

AH/ kJmol"

1

El fc(333K)/ kJ mol lmorV 1

k (400 K ) / lmol's 1

a-(CH3) C (0 )(CH ) OC(CH3)[(CH )3CH(CH,)]jCH3 -

3

6

2

2

2

158

cycto-[CH(NOH)(CH )3-CH(CH ) ]

-8.9

17.4

1.9

x

10

5

5.3

x

10

5

159

cyc/o-[CH(NOH)(CH ) -CH(CH ) ]

-5.5

19.1

1.0

x

10

5

3.1

x

10

5

172

cyc/o-[C(CH3) C(CH3) N=C(C,iH5)N(OH)]

-15.5

14.4

5.6

x

10

s

1.3

x

10

6

173

cvcto-[C(CH ) C(C H )=N(0)C(CH )(N(CH3)OH)N(OH)]

-17.7

13.4

7.8

x

10

5

1.8

x

10

6

200

l,2-C H5[C(C H )3]-cyc/o-[C(CH3)-CHC(CH3) N(OH)]

-38.2

4.8

1.8

x

10

7

2.4

x

10

7

201

C H [(CH )3C]NOH

7.0

25.3

1.1

X

10

4

5.0

x

10"

202

C H C(0)[(CH3) C]NOH

-4.7

19.4

9.1

x

10

4

2.9

x

10

5

207

[(CH ) C] C=NOH

10.8

27.3

5.3

x

10

5

2.7

x

10

4

208

(CF ) NOH

18.0

31.3

1.2

x

10

3

8.1

x

10

3

209

(CH ) CHN(OH)C(CH3)

25.0

35.2

3.0

x

10

2

2.5

x

10

3

211

(CH ) CHCH C(0)N(OH)C(CH )3

-11.2

27.6

4.7

x

10

3

2.5

x

10

4

213

C H CH=CHC(0)N(OH)C(CH )3

-6.3

18.7

1.2

x

10

5

3.8

x

10

3

214

4-C«H5C« H4C(0)N(OH)C(CH3)3

-3.3

20.1

6.9

x

10

4

2.4

x

10

s

215

C H CH CH C(0)N(OH)C(CH3)

-9.1

17.3

1.9

x

10

5

5.6

x

10

5

217

cyc/o-[C(CH ) (CH )3C(CH ) N(OH)]

-36.5

5.4

1.4

x

10

7

2.0

x

10

7

218

cvc/o-[C(CH ) CH CH(OCOC H )CH C(CH3) N(OH)]

-27.4

9.1

3.7

x

10*

6.5

x

10

6

220

cyc/o-[C(CH ) CHClC(0)CH C(CH ) N(OH)]

-19.8

12.4

1.1

X

10

6

2.4

x

10

6

221

cyc/o-[C(CHj) CH CH(OH)CH C(CH ) N(OH)]

-25.5

10.0

2.7

x

10

6

5.0

x

10

6

222

cycto-[C(CH ) CH C(0)CH C(CH ) N(OH)]

-27.3

9.2

3.4

x

10

fi

6.2

x

10*

227

cyc/o-[C(CH ) C(0)N(OH)C(CH3) N(OH)]

-21.7

11.6

1.5

x

10

5

3.1

x

10

6

232

c>-do-[C(CH3) N(0)=C(CH3)CH C(CH3) N(OH)]

-18.9

12.8

9.7

x

10

5

2.1

x

10

6

235

cycto-[C(CH3) CH C(C H )=CHC(CH ) N(OH)]

-31.8

7.4

6.9

x

10

6

7.2

x

10

3

237

l,2-C H,[C(C(iH )3]-cycto-[C(CH3XC H5)CH C(CH3) N(OH)]

-34.9

6.1

1.1

X

10

7

2.8

x

10

3

2

2

2

2

3

4

8

6

3

3

6

3

3

5

2

3

3

3

3

2

2

2

3

6

2

3

3

2

2

6

13

2

3

2

3

3

2

3

5

s

6

5

2

2

3

3

3

2

2

2

6

2

3

5

2

2

2

2

3

2

2

2

2

3

2

3

2

2

2

2

2

2

2

6

2

2

2

3

3

3

2

5

6

2

5

3

6

2

2

2

Ch. 5

Reactions of Hydroxylamines and Nitroxyl Radicals

117

Table 5.6 Enthalpies, activation energies and rate constants of reactions of sterically hindered phenoxyls with hydroxylamines in nonpolar solutions calculated by formulas 1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 e

No.

Hydroxylamine

AHI k J mol

1

El kJmol

1

k (333 K ) / * ( 4 0 0 K ) / Imol's" Imol's"' 1

2,6-[(CH3)3]2-4-CHjO-C,iH20*

158

cyc/o-[-CH(NOHXCH )3-CH(CH )3]

-11.9

27.0

5.8

x

10'

3.0

x

10

4

159

cyc/o-[-CH(NOHXCH ) -CH(CH ) ]

-8.5

28.6

3.3

x

10

3

1.8

x

10

4

172

cye;o-[C(CH3) C(CH3) N=C(C,iH5)N(OH)]

-18.5

23.9

1.8

x

10"

7.6

x

10

4

173

cyc/o-[C(CH3) C(C«H5)=N(0)C(CH )[N(CH3)OH]N(OH)]

-20.7

22.9

2.6

x

10

4

1.0

x

10

3

200

l,2-C H [C(C H5)3]-cyc/o-[C(CH3)=CHC(CH3) N(OH)]

-41.2

14.2

5.9

x

10

3

1.4

x

10

6

201

C H [(CH )3C]NOH

4.0

34.8

3.5

x

10

2

2.8

x

10

3

202

C H C(0)[(CH )3C]NOH

-7.7

29.0

2.8

x

10

3

1.6

x

10

4

207

[(CH ) C] C=NOH

7.8

36.7

1.8

x

10

2

1.6

x

10

3

208

(CF ) NOH

15.0

40.5

44

5.1

x

10

2

209

(CH ) CHN(OH)C(CH )

22.0

44.3

11

1.6

x

10

2

211

(CH ) CHCH C(0)N(OH)C(CH )3

-14.2

25.9

8.7

x

10

3

4.1

x

10

4

213

C H CH=CHC(0)N(OH)C(CH )3

-9.3

28.2

3.8

x

10

3

2.1

x

10

4

214

4-C H C«H4C(0)N(OH)C(CH3)3

-6.3

29.6

2.3

x

10

3

1.4

x

10

4

215

CWo-[-CH(NOH)(CH ) -CH(CH ) ]

-22.4

0.8

7.5 x 10

6

159

cycto-[-CH(NOHXCH ) -CH(CH ) ]

-19.0

4.8

1.8 x 10

6

172

cyc/o-tC(CH ) C(CH ) N=C(C H )N(OH)]

-29.0

0.4

8.7 x 10

173

c>'c/0-[C(CH ) C(C H5)=N(O)C(CH )(N(CH )OH)N(OH)]

-31.2

0.0

1.0 x 10

-51.7

2

2

3

3

2

3

2

3

2

2

3

2

2

6

3

5

(i

3

3

200

*(400K)/ lmol's"'

7.9 x 10* 2.4 x 10

6

6

8.9 x 10

6

7

1.0 x 10

7

0.0

1.0 x 10'

1.0 x 10

7

-6.5

10.7

2.1 x 10

4.0 x 10

5

-18.2

5.1

1.6 x 10*

2.2 x 10*

201

C H, [(CH ) C]NOH

202

CsHjCtCOKCH^qNOH

207

[(CH ) C] C=NOH

-2.7

12.7

1.0 x 10

5

2.2 x 10

s

208

(CF ) NOH

-4.5

11.7

1.5 x 10

5

3.0 x 10

s

209

(CH ) CHN(OH)C(CH )

11.5

20.4

6.3 x 10

3

2.2 x 10

4

211

(CH ) CHCH C(0)N(OH)C(CH )

-24.7

2.2

4.5 x 10

6

5.2 x 10

6

213

C H CH=CHC(0)N(OH)C(CH )

-19.8

4.3

2.1 x 10

6

2.7 x 10

6

214

4-C H C«H4C(0)N(OH)C(CH )

-16.8

5.8

1.2 x 10

6

1.7 x 10

6

215

C H CH CH C(0)N(OH)C(CH )

-22.6

3.1

3.3 x 10

6

3.9 x 10

6

221

cye/o-[C(CH ) CH CH(OH)CH C(CH ) N(OH)]

-39.0

0.0

1.0 x 10

7

1.0 x 10

7

222

cyc/o-[C(CH ) CH C(0)CH C(CH ) N(OH)]

-40.8

0.0

1.0 x 10

7

1.0 x 10

7

227

cyc/o-[C(CH ) C(0)N(OH)C(CH ) N(OH)]

-40.3

0.0

1.0 x 10

7

1.0 x 10

7

232

cydo-[C(CH ) N(0)=C(CH )CH C(CH ) N(OH)]

-32.4

0.0

1.0 x 10

7

1.0 x 10

7

235

cydo-[C(CH ) CH C(C H )=CHC(CH ) N(OH)]

-45.3

0.0

1.0 x 10

7

1.0 x 10

7

237

l,2-C6H [C(C,sH ) ]-cvcto-[C(CH XC6H )CH C(CH ) N(OH)]

-48.4

0.0

1.0 x 10

7

1.0 x 10

7

8

3

3

3

3

3

3

6

2

2

2

3

2

3

2

3

s

6

6

3

3

3

3

5

3

2

2

2

3

3

3

3

3

3

3

3

3

2

2

3

3

2

2

3

2

3

2

3

2

3

2

2

3

3

6

2

2

2

2

3

3

3

3

2

2

5

2

3

2

5

Ch. 5

Reactions of Hydroxylamines and Nitroxyl Radicals

121

Table 5.8 Rate constants of reactions of alkyl radicals with nitroxyl radicals Alkyl radical

Nitroxyl radical

77 K

kl 1 mol" s" or log k = 1

Ref.

1

A-E/Q

CH "

cyc/o-[N(0'X:(CH ) CH CH(CONH )C(CH ) ]

298

5.1 x 10

7

2

8

CH "

cycto-[N(0 )C(CH ) CH=C(CONH )C(CH ) ]

298

7.8 x 10

8

8

CHj

cyc/o-[N(0')C(CH ) CH(C(0)NH )C(CH ) ]

298

7.5 x 10

s

8

298

7.8 x 10

s

8

3

3

2

2

2

3

,

3

3

-

2

3

2

2

3

2

3

2

2

cyc/o-[N(0')C(CH ) CH=C(C(0)NH )C(CH ) ]

CH *

3

3

2

2

3

2

CH (CH ) C H2

cycto-[N(0')C(CH ) (CH ) C(CH ) ]

270-317

1 0 . 4 - 7.5/0

8

CH (CH ) C"H

cycto-[N(0')C(CH ) (CH ) C(CH ) ]

293

1.2 x 10

9

9

(CHj) C*

cyc/o-[N(0')C(CH ) (CH ) ]

293

7.6 x 10

8

9

(CH ) C"

l,2-cycto-[C(CH ) N(0")C(CH ) ]-C6H

293

8.8 x 10

8

9

293

9.6 x 10

8

9

,

3

2

3

3

7

2

7

3

2

3

3

(CH ) CC'H 3

3

3

2

3

3

3

2

3

3

2

3

3

2

2

3

2

3

2

3

2

4

cyc'o-[N(0 )C(CH ) (CH ) C(CH ) ] ,

3

2

2

2

3

3

2

cyc/o-[C'H(CH ) ]

cyc/o-[N(0")C(CH ) CH CH(C(0)NH )C(CH ) ]

298

3.5 x 10

8

8

cvc/o-[C'H(CH ) ]

cyc/o-[N(0')C(CH ) CH=C(C(0)NH )C(CH ) ]

298

3.6 x 10

8

8

cyclo-

l^-cyc/o-ICCCHj^NCO'JCCCft^-CsrL,

333-398

1 0 . 0 - 2.5/0

10

333-398

7 . 4 - 4.6/0

10

333-398

9 . 7 - 3.8/0

10

l,2-cyc/o-[C(CH ) N(0")C(CH ) ]-C6fL,

353

8 . 9 - 0.4/0

10

l,2-cycto-[C(CH ) N(0')C(CH ) ]-C H

333-398

1 0 . 0 - 4.2/0

10

ll-cyclo-lCiCUiWiO'yXCHih-CtiU

353

9 . 2 - 2.9/0

10

l^-cycto-ICCCHj^NCO^CCCHj^-Qli,

353

9 . 5 - 1.3/0

10

l^-cycto-lCCCHj^NCO'^CHj^l-Qrl,

333-398

9 . 6 - 2.1/0

10

l,2-cyc/o-[C(CH ) N(0'X^(CH ) ]-C H

353

8 . 5 - 2.1/0

10

cyc/o-[N(0*)C(CH ) (CH ) C(CH ) ]

293

4.9 x 10

cyclo- [N(0*)C(CH ) (CH ) C(CH ) ]

233-306

2

2

3

4

2

3

4

2

2

2

3

2

3

2

2

[CH(C"H )C(CH ) (CH ) ] 2

3

2

2

2

cvcto-[CH(C'H XCH ) ]

l,2-c>'cto-[C(CH ) N(0 )C(CH3) ]-C6H

CH =CH(CH ) C*H

l,2-cyc/o-[C(CH ) N(0 )C(CH ) ]-C H

2

2

2

2

3

3

2

2

3

3

2

2

2

CH =CHCH OCH C'(CH ) 2

2

2

CH =CHCH OC'H 2

2

3

2

CH =CHCH OCH C*H 2

2

2

2

CH =CHCH OCH C'HCH 2

2

CfiH5C*H

2

2

3

2

2

2

3

2

3

3

3

2

CfiHsC'Fk

2

2

2

3

2

2

(!

4

2

3

3

2

6

2

3

6

3

6

3

(C H,) C*H 6

2

9

293

5.5 x 10

8

9

cyc/o-rN(0')C(CH ) (CH ) C(CH ) ]

293

1.6 x 10

8

9

cyc'o-[N(0')C(CH ) (CH ) C(CH ) ]

293

1.2 x 10'

9

cyc/o-[N(0')C(CH ) (CH ) C(CH ) ]

293

4.6 x 10

9

2

2

3

2

3

2

s

9

3

C H5C"(CH )

4

2

3

2

l,2-cyc/o-[C(CH ) N(0')C(CH ) ]-C H

3

4

9 . 3 - 3.7/0

3

CgHsC H C H

4

-

CH =CHCH C(CH ) CH C'H 2

2

3

2

CH =CHC(CH ) C'H 2

,

3

2

3

3

3

2

2

2

2

2

2

3

3

3

2

6

3

3

3

2

2

2

4

7

122

Handbook of Antioxidants

AlkyI radical

Nitroxyl radical

T/K

Ref.

kl 1 mol" s" or log k = 1

A -

1

E/e

(GsHyjC'CHj

cvcto-[N(0')C(CH )2(CH2) C(CH )2l

293

4.6 x 10

1

9

1-C

H2-C10H7

cyc/o-[N(0'X:(CH )2(CH2) C(CH )2]

293

8.2 x 10

7

9

2-C

H2-C10H7

cyc/o-[N(0')C(CH )2(CH2) C(CH ) ]

293

5.7 x 10

7

9

3

3

3

3

3

3

3

3

3

2

C"H OH

cyc/o-[N(0*)C(CH )2CH CH(C(0)NH2)C(CH )2]

298

4.6 x 10

8

8

C*H OH

cyc/o-[N(0*)C(CH ) CH=C(C(0)NH2)C(CH )2]

298

3.5 x 10"

8

C*H OH

cyc/o-[N(0")C(CH )2CH=C(C(0)NH2)C(CH )2]

298

3.5 x 10"

8

C'H OH

cycZo-[N(0')C(CH )2CH=CH(C(0)NH )C(CH )2]

298

4.6 x 10

8

8

CH2CH2OH

cyc/o-[N(0')C(CH )2CH=CH(C(0)NH2)C(CH )2]

298

4.7 x 10

8

8

CH2CH2OH

cyc/o-[N(0*)C(CH ) CH=C(C(0)NH2)C(CH )2]

298

4.8 x 10

8

8

C H 3 C H O H

cyc/o-[N(0*)C(CH )2CH=C(C(0)NH2)C(CH ) ]

298

6.2 x 10

8

8

CH3CHOH

cvcto-[N(0*XJ(CH )2CH CH(C(0)NH2)C(CH )2]

298

4.3 x 10

8

8

CH,C'HOH

cycto-fNCO^CCC^JjCHjCHCCCOJNHjX^C^^]

298

4.7 x 10

s

8

C*H C(CH3)20H

cyc/o-[N(0')C(CH )2CH2CH(C(0)NH )C(CH )2]

298

1.8 x 10

8

8

C'H C(CH3) OH

cyc/o-[N(0')C(CH )2CH=C(C(0)NH2)C(CH )2]

298

2.0 x 10

s

8

(CH ) C'OH

cyc/o-[N(0*)C(CH ) CH2CH(C(0)NH2)C(CH )2]

298

3.3 x 10

s

8

(CHj) C*OH 2

cyc/o-[N(0')C(CH ) CH=C(C(0)NH )C(CH ) ]

298

3.6 x 10"

8

(CH )2C*OH

cyc/o-[N(0*)C(CH ) CH=C(C(0)NH )C(CH ) ]

298

3.6 x 10

8

8

(CH ) C"OH

cyc/o-[N(0'X:(CH )2CH CH(C(0)NH2)C(CH )2]

298

3.3 x 10

8

8

(C H ) C'OH

l,2-cyc/o-[/C=C/NH-

295.5

2.6 x 10

7

11

295.5

5.0 x 10

7

11

298

1.8 x 10

8

8

2

2

3

2

3

2

3

3

3

3

2

3

3

2

3

2

3

3

2

3

3

2

3

3

2

3

3

2

2

2

3

2

2

3

2

3

2

2

3

3

2

5

3

3

2

6

2

3

2

3

3

3

2

3

2

3

2

3

cycto-[C(CH )2N(0 )C(CH )2CH2]-C „H ,

3

3

1

6

(C H )2C'OH

c^c/o-[N(0')C(CH ) CBr=C(CN)C(CH ) ]

C'H C(CH ) OH

cyc/o-[N(0')C(CH )2CH2CH(C(0)NH )C(CH )2]

6

5

2

3

3

2

2

3

2

2

3

3

CH (OHXCHOH) C'(0)

cyc/o-[N(0')C(CH )2CH2CH(C(OH)NH )C(CH ) ]

298

5.1 x 10

7

2

8

C"H2C(CH ) OH

cyc/o-[N(0")C(CH ) CH=C(C(OH)NH )C(CH ) ]

298

2.0 x 10

8

8

CH (OHXCHOH)4C*(0)

c^c/o-[N(0')C(CH ) CH=C(C(0)NH )C(CH ) ]

298

4.3 x 10

7

8

CH (OHXCHOH)4C'(0)

cyc/o-INCO'^CHj^CHjCHCC^NH^CCCHj^]

298

5.1 x 10

7

8

CH2(OHXCHOH) C*(0)

cyc/o-[N(0")C(CH3) CH=C(C(0)NH )C(CH3) ]

298

4.3 x 10

7

8

cyclo[(CH )3CH(C(CH,)20C-(0)]

1 ^-cycto-ICCCHj^CO^CHjW-QrU

353

9.7-2.5/8

2

4

3

2

2

3

3

2

2

4

3

2

2

2

2

2

2

2

Solvent — H 0 , Isooctane, cyclo-C^ 8

2

9

,

1 0

3

1-Propanol.

11

3

3

2

2

2

10

Ch. 5

Reactions of Hydroxylamines and Nitroxyl Radicals

123

Table 5.9 Rate constants of disproportionation of nitroxyl radicals Nitroxyl radical

Solvent

77 K

2kl 1 mol" s" or lQE(2/l)-£y9

Ref.

5.1-2.5/0

12

298

3.6 x 10

7

13

1

1

(CfthNO'

CF C1

CH3N(0')H

C H

(CH CH ) NO*

(CH^CHCrfeCHj

298

6.6 x 10"

14

(CH CH ) NO"

C H

298

2.7 x 10"

14

(CH CH ) NO*

CF C1

298

3.1 x 10

4

14

(CrkCH^NO*

CHjOH

298

3.0 x 10'

14

(CHJCH )JNO*

H 0

298

1.6 x 10

14

(CH CH ) NO

C6H6

3

2

3

6

2

2

3

2

6

2

2

2

#

2

2

3

2

CH CH N(0*)CH(OH)CH 3

2

2

2

2

H 0 CF C1 2

2

2

(CH ) CHN(0*)H 3

2

CH (CH ) C(0)N(0')CH 3

2

3

C6H CH 3

3

CH CH CH(CH )C(0)N(0')CH 3

2

3

CH CH CH(CH )C{0)N(0')CD 3

2

3

3

(CH ) CC(0)N(0')CH 3

3

3

15

3

251-298

7.9 - 39.3/0

12

301-341

8.9-10.5/9

13



4.9 - 5.9/9

16

3

4.0 - 10.5/9

16

8 . 7 - 10.5/9

13

4.3 - 13.0/0

16

4.0 x 10

17

2

5

3

287-345

298-328

CgHsCHs

3

17

4.6-15.1/0

16 18

313

1.2 x 10

C H 6

6

313

1.0

C H

6

297

2.1 x 10

2,3,5,6-(CH )4C rrN(0 XCH )5CH3

C^Ho

313

50

(C H ) C=NO'

C H C1

C«H N(0')H

C6H

C6H5(CH )C=NO*

C6His

3

2

5

3

6

3

CH (CH ) (C H )CHN(0')C(CH ) 3

2

5

6

5

3

[(CH ) C] C=NO* 3

3

6

2

,

3

6

3