Table Of ContentH A N D B O O K OF
ANTIOXIDANTS
Bond Dissociation Energies,
Rate Constants,
Activation Energies
and
Enthalpies of Reactions
Evguenii Denisov
Boca Raton London New York
CRC Press
CRC Press is an imprint of the
Boca RaTtaoynlo r &N Freawnc isY Gororukp , anL inofonrdmoa nb usinTesoskyo
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 not-
for-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
2
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.
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 Evguenii T. Denisov
June 19, 1995
CONTENTS
PREFACE
LIST OF CHEMICAL SYMBOLS
LIST OF PHYSICO-CHEMICAL SYMBOLS
Chapter 1 KINETICS AND MECHANISM OF INHIBITED OXIDATION
OF HYDROCARBONS 1
1.1 Mechanism of autoxidation of hydrocarbons 1
1.2 Mechanism of hydrocarbon oxidation inhibited by acceptors
of peroxyl radicals 2
1.3 Kinetics of inhibited autoxidation of hydrocarbons 5
1.4 Mechanisms of cyclic chain termination 8
1.5 The parabolic transition state model as semiempirical method
of evaluation of activation energies of free radical reactions
with hydrogen atom abstraction 14
REFERENCES 17
Chapter 2 RATE CONSTANTS OF ELEMENTARY STEPS OF CHAIN
OXIDATION OF HYDROCARBONS 19
Table 2.1 Enthalpies, activation energies and rate constants of reaction
R0 '+ RH -> ROOH + R*, E calculated by formulas 1.15-1.17,
2
1.21. The values of A, br and a, see Table 1.6 19
e
Table 2.2 Rate constants of isomerization and monomolecular decomposition
of peroxyl radicals 23
Table 2.3 Rate constants of addition of peroxyl radicals to double bond
of olefins 24
Table 2.4 Rate constants of addition of alkyl radicals to molecular oxygen 27
Table 2.5 Rate constants of recombination and disproportionation of peroxyl
radical in hydrocarbon solutions 27
Table 2.6 Rate constants of disproportionation of two peroxyl radicals
of different structure 30
Table 2.7 Rate constants of decomposition of azo-compounds into free radicals
in liquid phase 32
Table 2.8 Rate constants of decomposition of peroxides into free radicals
in liquid phase 33
Table 2.9 Rate constants of monomolecular decay of hydroperoxides in gas
phase and aromatic solvents 35
Table 2.10 Rate constants and activation energies of free radical formation
by reaction ROOH + Y ->• free radicals 35
Contents
Table 2.11 Rate constants and activation energies of reaction
RH + 0 -» R* + H0 * 37
2 2
Table 2.12 Rate constants and activation energies of trimolecular reaction
2 RH + 0 -> free radicals 38
2
REFERENCES 39
Chapter 3 BOND DISSOCIATION ENERGIES AND RATE CONSTANTS
OF REACTIONS OF PHENOLS 47
Table 3.1 O—H-Bond dissociation energies of phenols 47
Table 3.2 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
e
and a, see Table 1.6 56
Table 3.3 Enthalpies, activation energies and rate constants of reaction
of peroxyl radicals with sterically hindered phenols (ArOH)
2
in hydrocarbon solutions calculated by formulas 1.15-1.17 and 1.21.
The values of A, br and a, see Table 1.6 59
e
Table 3.4 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 63
e
Table 3.5 Enthalpies, activation energies and rate constants of reaction
of sterically hindered phenoxyls (Ar0*) with secondary and tertiary
2
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 65
e
Table 3.6 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 68
e
Table 3.7 Enthalpies, activation energies and rate constants of reaction
of />ara-methoxyphenoxyl radical (A^O") with sterically hindered
phenols (ArOH) in hydrocarbon solutions calculated by formulas
2
1.15-1.17 and 1.21. The values of A, br and a, see Table 1.6 70
e
Table 3.8 Enthalpies, activation energies and rate constants of reaction
of 2,4,6-tert-butylphenoxyl radical (Ar0*) with different phenols
2
(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 71
e
Table 3.9 Rate constants of reaction of phenoxyl radicals with peroxyl
radicals in hydrocarbon solutions, Ci4H 0 * — peroxyl radical from
n 2
9,10-dihydroanfhracene 73
Table 3.10 Rate constants of recombination and disproportionation of phenoxyl
radicals in hydrocarbon solutions measured by flash photolysis
technique 74
Table 3.11 Rate constants of disproportionation of two different phenoxyl
radicals in hydrocarbon solutions 75
Table 3.12 Activation energies and rate constants of reaction of phenols
(AriOH) with 0 in hydrocarbon solutions calculated by formula
2
1.17 alA = 10101 mol"1 s"1 and E = AH 76
Contents
Table 3.13 Activation energies and rate constants of reaction of sterically
hindered phenols (ArOH) with 0 in hydrocarbon solutions
2 2
calculated by formula 1.17 at A = 1010 1 mol"1 s"1 and E = AH 78
Table 3.14 Rate constants of reaction of phenols with hydroperoxides 79
Table 3.15 Rate constants, preexponential factors and activation energies
of decay of quinolide peroxides ROOR; in benzene at 363 K 80
Table 3.16 The values of stoichiometric coefficients of chain termination
by phenols in oxidizing substances RH 81
REFERENCES 83
Chapter 4 BOND DISSOCIATION ENERGIES AND RATE CONSTANTS
OF REACTIONS OF AROMATIC AMINES 85
Table 4.1 Dissociation energies of N—H-bonds in aromatic amines 85
Table 4.2 Enthalpies, activation energies and rate constants of reaction
of peroxyl radicals (R0*) with aromatic amines calculated by
2
formulas 1.15-1.17 and 1.20. The values of A, br and a,
e
see Table 1.6 87
Table 4.3 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
e
and a, see Table 1.6 90
Table 4.4 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
e
and a, see Table 1.6 92
Enthalpies, activation energies and rate constants of reaction
Table 4.5
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 93
e
Rate constants of recombination and disproportionation of aminyl
Table 4.6
radicals in hydrocarbon solutions measured by flash photolysis
technique. Products and mechanism see in papers 94
Rate constants of reaction of paradisubstituted diphenylaminyl
Table 4.7
radicals with phenols in decane estimated by laser
photolysis technique 95
Enthalpies, activation energies and rate constants of reaction
Table 4.8
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 96
Rate constants of reaction of aromatic amines with oxygen:
Table 4.9
AmH + 0 ->• Am* + H0* calculated by formula 1.17
2 2
with A = 3 x 1010 1 moP1 s"1 per one N—H-bond and E = AH 97
The values of nonstoichiometric coefficients of chain termination
Table 4.10
by aromatic amines in oxidizing substances RH with cyclic
chain termination 98
REFERENCES 99
