Metal Promoted Selectivity in Organic Synthesis

222 Pages·1991·12.92 MB·English

by  W. Keim (auth.), A. F. Noels, M. Graziani, A. J. Hubert (eds.)

ORGANOMETALLIC MODELING OF THE HYDRODESULFURIZATION
AND HYDRODENITROGENATION REACTIONS
Catalysis by Metal Complexes
Volume 24
Editors:
B. R. James, The University of British Columbia, Vancouver, Canada
P. W. N. M. van Leeuwen, University of Amsterdam, The Netherlands
Advisory Board:
I. Horváth, Exxon Corporate Research Laboratory, Annandale, NJ, U.S.A.
S. D. Ittel, E. I. du Pont de Nemours Co., Inc., Wilmington, Del., U.S.A.
A. Nakamura, Osaka University, Osaka, Japan
W. H. Orme-Johnson, M.I.T., Cambridge, Mass., U.S.A.
R. L. Richards, John Innes Centre, Norwich, U.K.
A. Yamamoto, Waseda University, Tokyo, Japan
The titles published in this series are listed at the end of this volume.
ORGANOMETALLIC MODELING
OF THE
HYDRODESULFURIZATION
AND HYDRODENITROGENATION
REACTIONS
by
Roberto A. Sánchez-Delgado
Instituto Venezolano de Investigaciones Científicas (IVIC),
Caracas, Venezuela
KLUWER ACADEMIC PUBLISHERS
NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOW
eBook ISBN: 0-306-47619-3
Print ISBN: 1-4020-0535-0
©2002 Kluwer Academic Publishers
New York, Boston, Dordrecht, London, Moscow
Print ©2002 Kluwer Academic Publishers
Dordrecht
All rights reserved
No part of this eBook may be reproduced or transmitted in any form or by any means, electronic,
mechanical, recording, or otherwise, without written consent from the Publisher
Created in the United States of America
Visit Kluwer Online at: http://kluweronline.com
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To Vicky, Eugenia, and Alexander
CONTENTS
PREFACE xi
CHAPTER 1.
HYDRODESULFURIZATION AND HYDRODENITROGENATION
1.1. Introduction 1
1.2. The Hydrodesulfurization Reaction 3
1.2.1. SULFUR COMPOUNDS IN PETROLEUM AND FUELS 3
1.2.2. HDS CATALYSTS 5
1.2.3. REACTION MECHANISMS 7
1.2.4. THE ACTIVE SITES 8
1.2.4.1. The Co-Mo-S model 9
1.2.4.2. Active sites and the concept of vacancies 12
1.2.5. THE ACTIVATION OF HYDROGEN 14
1.2.6. CHEMISORPTION OF ORGANOSULFUR COMPOUNDS 16
1.2.7. HYDROGENATION AND HYDROGENOLYSIS
OF ADSORBATES 18
1.2.7.1. HDS of thiophenes 18
1.2.7.2 HDS of benzothiophenes and dibenzothiophenes
and the deep desulfurization issue 20
1.3. The Hydrodenitrogenation Reaction 25
1.3.1. CHEMISORPTION OF ORGANONITROGEN
COMPOUNDS 26
1.3.2. MAIN REACTION PATHWAYS AND MECHANISMS
IN HDN 28
References 32
CHAPTER 2.
COORDINATION AND ACTIVATION OF THIOPHENES
IN METAL COMPLEXES
2.1. Introduction 35
2.2. metal thiophene complexes 37
2.3. metal thiophene complexes 43
vii
viii TABLE OF CONTENTS
2.4. metal thiophene complexes 46
2.5. metal thiophene complexes 47
2.6. metal thiophene complexes 50
2.7. metal benzothiophene and
dibenzothiophene complexes 57
2.8. Conclusions and further comments 59
References 59
CHAPTER 3.
HYDROGENATION REACTIONS
3.1 Introduction 62
3.2. Homogeneous Hydrogenation of Aromatic Hydrocarbons 63
3.2.1. THE CATALYSTS 63
3.2.2. REACTION MECHANISMS 65
3.2.2.1. Allyl metal complexes 66
3.2.2.2. Cyclopentadienyl and arene metal complexes 69
3.2.2.3. Other metal complexes 71
3.2.2.4. Tethered complexes on supported metals 72
3.2.3. CONCLUSIONS AND PERSPECTIVES 73
3.3 Homogeneous Hydrogenation of Heteroaromatic Hydrocarbons 75
3.3.1. SULFUR CONTAINING HETEROAROMATICS 75
3.3.1.1. Thiophene hydrogenation 75
3.3.1.2. Benzothiophene hydrogenation 78
3.3.1.3. Benzothiophene hydrogenation as a pretreatment for HDS 83
3.3.2. NITROGEN CONTAINING HETEROAROMATICS 84
3.3.2.1. Hydrogenation of pyridines 85
3.3.2.2. Hydrogenation of polynuclear N-heterocycles 85
References 92
CHAPTER 4
RING OPENING, HYDROGENOLYSIS AND DESULFURIZATION
OF THIOPHENES BY METAL COMPLEXES
4.1. Introductio n 95
TABLE OF CONTENTS ix
4.2. Stoichiometric ring opening, hydrogenolysis,
and desulfurization of thiophenes 96
4.2.1. REACTIONS OF THIOPHENES
ON MONONUCLEAR COMPLEXES 97
4.2.1.1. Complexes with cyclopentadienyl and related ligands 97
4.2.1.2. Complexes with phosphine ligands 101
4.2.2. REACTIONS OF THIOPHENES
ON DINUCLEAR AND POLYNUCLEAR COMPLEXES 114
4.2.2.1. Homopolynuclear complexes 114
4.2.2.2. Heteropolynuclear complexes 119
4.2.2.3. Curtis’ Co-Mo-S clusters 123
4.3. Homogeneous Catalytic Hydrogenolysis
and Hydrodesulfurization of Thiophenes 127
4.4. Further remarks on the relations between
homogeneous and heterogeneous hydrogenolysis
and HDS of thiophenes 134
References 135
CHAPTER 5.
ACTIVATION OF HYDROGEN ON METAL COMPLEXES
WITH SULFIDE LIGANDS AND RELATED
COORDINATION CHEMISTRY OF
5.1 Introduction 138
5.2 Hydrogen activation on dinuclear complexes
containing sulfido or disulfido ligands 140
5.3 Hydrogen activation on mononuclear
and complexes 143
5.4. Reactions of with metal complexes 145
5.5 Conclusions and remarks 151
References 151
CHAPTER 6.
MODELING HYDRODENITROGENATION
6.1 Introduction 153
6.2 Binding Modes of N-Heterocycles in
Transition Metal Complexes 154
x TABLE OF CONTENTS
6.2.1 COMPLEXES WITH PYRROLE, INDOLE
AND CARBAZOLE LIGANDS 154
6.2.2. COMPLEXES WITH PYRIDINE, QUINOLINE,
AND RELATED LIGANDS 162
6.3 Reactions of N-Heterocycles in Transition Metal Complexes 168
6.3.1. REACTIONS OF COORDINATED PYRROLES,
INDOLES, AND RELATED COMPONDS 168
6.3.2. REACTIONS OF COORDINATED PYRIDINES,
QUINOLINES, AND RELATED COMPOUNDS 171
6.3.3. HYDROGENOLYSIS OF N-HETEROCYCLES
CATALYSED BY TRANSITION METAL COMPLEXES 173
6.4 C-N Bond Activation of Amines, Imines,
and Amides by Transition Metal Complexes 174
6.5. Final Remarks 177
References 178
EPILOGUE 181
Vacancies 184
The nature and the structure of the active sites 185
Hydrogen activation 186
Chemisorption modes and reactivity 188
Sulfur extrusion 190
A general mechanism for HDS on Co-Mo-S sites 191
Hydrodenitrogenation 194
Concluding remarks 194
ABBREVIATIONS 196
LIST OF FIGURES 197
LIST OF TABLES 201
INDEX 202
PREFACE
The fields of hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) continue to
attract the attention of researchers in the various disciplines connected to these
fascinating problems that represent two of the key outstanding chemical challenges for
the petroleum refining industry in view of their very strong environmental and
commercial implications. One area that has flourished impressively over the last 15
years is the organometallic chemistry of thiophenes and other related sulfur-containing
molecules. This has become a powerful method for modeling numerous surface species
and reactions implicated in HDS schemes, and nowadays it represents an attractive
complement to the standard procedures of surface chemistry and heterogeneous catalysis,
for understanding the complex reaction mechanisms involved in this process. Similar
developments have begun to appear in connection with HDN mechanisms, although in a
much more modest scale and depth.
Some years ago when, encouraged by Prof. B. R. James, this book was
planned, several excellent reviews and monographs treating different aspects of HDS
were already available including some on the subject of organometallic models.
However, it seemed appropriate to try to summarize the most striking features of this
chemistry in an updated and systematic way, and inasmuch as possible in connection
with the common knowledge and beliefs of the mechanisms of heterogeneous HDS
catalysis. Hopefully, this attempt to build some conceptual bridges between these two
traditionally separated areas of chemistry has met with some success. The timeliness of
this idea has probably increased during the period of writing and publishing of this
manuscript, as evidenced by the increasing number of papers, patents and scientific
meetings devoted to the subject of HDS and HDS modeling, and by the frequency with
which one now sees organometallic and surface chemists referring to the each other’s
work in a natural way and as part of a common way of thinking toward the solution of
an important environmental and industrial problem. It also seemed appropriate to try to
summarize our current knowledge on the subject of organometallic modeling of the
HDN reaction, since the literature available, though scarce and generally scattered,
clearly indicates that this is a very important and yet a very open field for future
research.
The completion of this project was considerably facilitated by being the
recipient of a John Simon Guggenheim Fellowship (December 1998-January 2000)
during which most of the preparation of the book was accomplished. I am most grateful
to the Chemistry Department of the University of California at Berkeley for providing
an excellent environment for initiating this work during the period December 1998-
March 1999. Particularly to Prof. R. A. Andersen who kindly made the arrangements for
my stay there, and dedicated many hours to discuss chemistry with me; to Prof. R. G.
Bergman for his generous hospitality, and to many other colleagues and enthusiastic
xi