Table Of ContentBimodal Oxidation: Coupling
of Heterogeneous and
Homogeneous Reactions
Bimodal Oxidation: Coupling
of Heterogeneous and
Homogeneous Reactions
Robert Bakhtchadjian
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2020 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Printed on acid-free paper
International Standard Book Number-13: 978-0-367-27259-3 (Hardback)
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 here-
after 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
Names: Bakhtchadjian, Robert, author.
Title: Bimodal oxidation : coupling of heterogeneous and homogeneous reactions /
Robert Bakhtchadjian.
Description: Boca Raton : CRC Press, Taylor & Francis Group, 2019. | Includes
bibliographical references.
Identifiers: LCCN 2019016625 | ISBN 9780367272593 (hardback : alk. paper)
Subjects: LCSH: Oxidation. | Heterogeneous catalysis. | Homogeneous catalysis.
Classification: LCC QD63.O9 B35 2019 | DDC 541/.393–dc23
LC record available at https://lccn.loc.gov/2019016625
Visit the Taylor & Francis Web site at
http://www.taylorandfrancis.com
and the CRC Press Web site at
http://www.crcpress.com
In Memory of My Parents,
Harutyun Bakhtchadjian and Sima Keshishian
Contents
Introduction ..............................................................................................................1
Chapter 1 Bimodal Reaction Sequences Occurring through the Active
Intermediates ......................................................................................5
1.1 About the Classification of Chemical Reactions ...................5
1.2 Active Intermediate Species ....................................................8
1.3 Historical Background of the Early Notions about
Heterogeneous–Homogeneous Reactions ..............................9
1.4 The Revelation of the Heterogeneous Stages in
Homogeneous Reaction .........................................................14
1.5 Frontiers of the Heterogeneous, Heterogeneous–
Homogeneous and Homogeneous Reactions .......................19
1.6 Thermodynamic and Kinetic Aspects of the Bimodal
Reaction Sequences ...............................................................24
1.6.1 Conjugate Reactions: Thermodynamic and
Kinetic Conjugation ...................................................25
1.6.2 Thermodynamics of the Irreversible Chemical
Processes Applied in Bimodal Reactions...................30
1.7 Suggestions of the Reaction Mechanisms in
Heterogeneous–Homogeneous Reactions ............................33
1.7.1 Notes about the Classifications of Reaction
Mechanisms ................................................................33
1.7.2 Heterogeneous–Homogeneous Pathway in
Mechanism Suggestions .............................................38
1.8 Desorption of Active Intermediate Species. Relation
of the Heterogeneous–Homogeneous Reaction to the
Principle of Sabatier ..............................................................40
1.9 The Role of Acid–Base and Redox Properties of Solid
Substances in Generation of Active Intermediates ............43
References .........................................................................................47
Chapter 2 Heterogeneous Generation and Reactions of Radicals.
Heterogeneous–Homogeneous Reactions of Radical
Decomposition ...................................................................................57
2.1 Radicals and Radical‑Like Species ......................................57
2.2 Heterogeneous Reactions by Participation of Radicals .....61
2.2.1 Examples of Non-Chain-Radical Reactions on
the Surface of Solid Substances .................................62
2.2.2 Examples of Heterogeneous Chain-Radical
Reactions ....................................................................64
vii
viii Contents
2.3 Heterogeneous–Homogeneous Reactions of Radical
Decomposition ........................................................................66
2.3.1 Heterogeneous–Homogeneous Pyrolysis
of Hydrocarbons .........................................................68
2.3.2 Heterogeneous–Homogeneous Decomposition
of Peroxide Compounds .............................................72
2.3.2.1 Heterogeneous–Homogeneous
Decomposition of Hydrogen Peroxide ........72
2.3.2.2 Heterogeneous–Homogeneous
Decomposition of Organic Peroxides .........77
References .........................................................................................81
Chapter 3 Bimodal Reaction Sequences in Oxidation of Hydrogen
and Organic Compounds with Dioxygen .......................................89
3.1 Oxidation with Dioxygen.......................................................89
3.2 Electronic Structure of Dioxygen .........................................91
3.3 Symmetry Considerations. Application of the
Wigner–Witmer Rules in Oxidation with Dioxygen ..........95
3.4 Reactivity of Dioxygen and Active Intermediate
Species of Oxygen in Heterogeneous–Homogeneous
Oxidation ................................................................................99
3.4.1 Reactivity of Dioxygen in Oxidation ..........................99
3.4.1.1 Reactivity of Dioxygen ...............................99
3.4.1.2 Activation of Dioxygen on the Surfaces
of Noble Metals ..........................................99
3.4.1.3 Activation of Dioxygen on the Surface
of the Metal Oxides ..................................101
3.4.2 Reactivity of Oxygen Species on Solid Surfaces
and in the Fluid Phases .............................................105
3.4.2.1 Oxygen Atom and Ion–Radical O− ...........107
3.4.2.2 Superoxide Ion-Radicals ...........................111
3.4.2.3 Hydroxyl Radicals ....................................112
3.4.2.4 Hydroperoxyl Radicals .............................114
3.4.2.5 Oxygen-Centered Peroxy Radicals ...........116
3.4.2.6 Anion and Cation Radicals .......................118
3.4.2.7 Singlet Oxygen ..........................................119
3.5 Heterogeneous–Homogeneous Reactions of Oxidation
with Dioxygen .......................................................................120
3.5.1 Catalytic Reaction of Oxidation of Hydrogen
with Dioxygen ..........................................................121
3.5.1.1 Adsorption and Reactivity of Reactants
on the Surfaces..........................................121
3.5.1.2 Suggestions of the Reaction
Mechanism in Hydrogen Oxidation ..........123
3.5.2 Oxidation of Hydrocarbons with Dioxygen .............128
Contents ix
3.5.2.1 Notes about Oxidation of Hydrocarbons ..129
3.5.2.2 Oxidative Coupling of Methane ...............138
3.5.2.3 Catalytic Oxidation of Propylene .............144
3.5.2.4 Conclusions about Heterogeneous–
Homogeneous Oxidation of
Hydrocarbons .........................................145
3.5.3 Oxidation of Alcohols with Dioxygen ......................147
3.5.3.1 Heterogeneous Generation of
Intermediates in Oxidation of Alcohols ...148
3.5.3.2 Bimodal Reaction Sequences in
Oxidation of Alcohols on Metals and
Metal Oxides.............................................149
3.5.4 Oxidation of Aldehydes with Dioxygen ...................155
3.5.4.1 Heterogeneous and Heterogeneous–
Homogeneous Oxidation of
Formaldehyde ...........................................157
3.5.4.2 Heterogeneous and Heterogeneous–
Homogeneous Oxidation of
Acetaldehyde and Propionaldehyde ..........160
3.5.4.3 Intermediates in Heterogeneous
Oxidation of Acetaldehydes and
Propionaldehyde .......................................166
3.6 Concluding Notes about the Bimodal Reaction
Sequences in Thermal Oxidation .......................................172
References .......................................................................................175
Chapter 4 Bimodal Reaction Sequences in Oxidation with Dioxygen
in Photocatalysis .............................................................................195
4.1 From Olden to Modern Photochemistry ...........................195
4.2 Preliminary Notes about Photocatalytic Reactions ..........197
4.2.1 Homogeneous Photocatalysis ...................................199
4.2.2 Heterogeneous Photocatalysis ..................................201
4.3 Heterogeneous Photogeneration of Radicals .....................203
4.4 Heterogeneous–Homogeneous Mechanisms
in Photochemical Oxidation ...............................................206
4.4.1 Oxidation of Some Organic Compounds on the
Heterogeneous Photocatalysts ..................................206
4.4.2 Examples of Heterogeneous Photocatalytic
Reactions Occurring by the Heterogeneous–
Homogeneous Pathway ............................................210
4.4.3 Detection of Radicals in Photocatalytic Oxidation .....213
4.5 Concluding Remarks about the Heterogeneous–
Homogeneous Mechanisms in Oxidation on the
Heterogeneous Photocatalysts ............................................217
References .......................................................................................219
