Table Of ContentFundamental Research in
Homogeneous
Catalysis
Volume 3
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Fundamental Research in
Homogeneous
Catalysis
Volume 3
Edited by
Minoru Tsutsui
Texas A & M University
College Station, Texas
Plenum Press· New York and London
Library of Congress Cataloging in Publication Data
International Workshop on Fundamental Research in Homogeneous Catalysis, 1st,
Santa Flavia, Italy, 1976; 2d, Shiga, Japan, 1977.
Fundamental research in homogeneous catalysis.
Vol. 3, edited by M. Tsutsui contains the proceedings of the 1st International
Conference on Homogeneous Catalysis, Corpus Christi, Texas, Nov. 29-Dec. 1,
1978.
Includes bibliographical references and indexes.
1. Catalysis - Congresses. I. Tsutsui, Minoru, 1918· II. Ugo, Renato. III.
Ishii, Yoshio, 1914· IV. International Conference on Homogeneous Catal-
ysis, 1st, Corpus Christi, Texas, 1978. V. Title.
QD505.I6 1976 541'.395 77·13024
ISBN-13: 978-1-4613-2960-2 e-ISBN-13: 978-1-4613-2958-9
DOr: 10.1007/978-1-4613-2958-9
Proceedings of the First International Conference on
Homogeneous Catalysis, held in Corpus Christi, Texas,
November 29-December 1, 1978
© 1979 Plenum Press, New York
Softcover reprint of the hardcover 1st edition 1979
A Division of Plenum Publishing Corporation
227 West 17th Street, New York, N.Y. 10011
All rights reserved
No part of this book may be reproduced, stored in a retrieval system, or transmitted,
in any form or by any means, electronic, mechanical, photocopying, microfilming,
recording, or otherwise, without written permission from the Publisher
ORGANIZING COMMITTEE
D. Bergbreiter, Texas A&M University
J. Halpern, University of Chicago
R. Pettit, University of Texas
M. Tsutsui, Chairman, Texas A&M University
J. Unruh, Celanese Corporation
INTERNATIONAL ADVISORY BOARD
J. Bassett, Centre National de La Recherche Scienttfique
C. Casey, University of Wisconsin
J. Chatt, The University of Sussex
R. Grubbs, Michigan State University
Y. Ishii, Chubu Institute of Technology
J. Lewis, Cambridge
I. Mador, Allied Chemical Corporation
L. Marko, University of Chemical Industries and Research Group for
Petrochemistry of the Hungarian Academy of Sciences
C. Masters, Shell Chemicals, U.K. Ltd.
E. Muetterties, Cornell University
G. Parshall, E. I. Du Pont de Nemours and Company
P. Pino, Eidegossiche Technische Hochschule Zurich
J. Roth, Monsanto Chemical Co.
A. Shilov, Academy of Sciences of U.S.S.R.
P. Teyssie, University de Liege
I. Tkatchenko, Institute de Recherche sur la Catalyse
R. Ugo, Istituto di Chimica Generale, G.N.R. dell Universita
K. Vrieze, Universiteit van Amsterdam
G. Wilke, Max Planck Institut fur Kohlenforschung
Preface
During the 70's it has become drastically apparent that our natural resources,
including energy, are not in unlimited supply. This realization is strongly felt in the
economic turmoil that is occurring, but its effects will penetrate into other areas, even
causing moderate social changes. Chemists playa major role in coverting the world's
natural resources into products. The public consumes these products and now depends
upon them to keep the high standard of living to which they have become accustomed.
This topic could easily be expounded into a whole article, but it is sufficent to say that
almost everything-from the use of lightweight, strong polymers which are replacing
the use of metals in today's automobiles, to the curing of diseases with asymetrically
synthesized drugs-is related to the endeavors of chemistry. Catalysts have played a major
role in transforming resources to useful products. Since a catalyst lowers the activation
energy required for a particular reaction, and often for only one specific pathway where
normally many exist, it is not surprising within the extant climate that researchers are
now increasing their efforts and focusing their priorities on improving and discovering
more efficient and selective catalysts.
Reactions involving catalysts classically have been separated into two divisions,
depending upon the physical nature of the catalyst. Heterogeneous catalysis employs
reactions occurring upon the surface of a solid phase, while homogeneous catalysis
involves dispersion of the catalyst throughout the reacting medium. Although, because
of engineering priorities, most industrial processes involve heterogeneous catalysts there
are well over 20 commercial processes that use homogeneous catalysts. This number is
steadily increasing since many of the problems associated with homogeneous catalysis
are being overcome and the advantages of higher selectivity often adds an economical
incentive to the process. The high costs of energy also makes it more rewarding to run
a reaction at low temperatures with a homogeneous catalyst rather than at the high tem
peratures usually associated with heterogeneous catalysis. For these and other reasons,
homogeneous catalysis is presently a very vibrant and active area of industrial research.
Recently, the First International Symposium on Homogeneous Catalysis was
held from November 29 through December 1, 1978 in Corpus Christi, Texas. Although
preregistration indicated that around 350 scientists were interested, over 850 participants
attended. The symposium was truly international as lO of the 19 plenary lectures were
from outside of the U.S.A. Although the exchange of ideas by scientists from differing
nations is a very rewarding purpose of any international symposium, even more out
standing were the discussions and contacts made between academic scientists and industrial
scientists. In many areas of science there is a large division between academic and industrial
vii
viii PREFACE
research. However, in the field of homogeneous catalysis both sides are striving for the
same goals, and so with only minor exceptions to proprietary information, ideas and
concepts were exchanged freely. In fact, the program was solely financed by industrial
support.
The symposium was devoted to the present state of the art of homogeneous
catalysis. The plenary lectures covered a wide range of topics and, most importantly,
just about every major active area of homogeneous catalysis was discussed. Most of the
information presented was relatively new and some material has not been previously
published or presented.
The first plenary session commenced with opening remarks by M. Tsutsui (Texas
A & M University), welcoming and introducing the audience to Texas and to the present
day challenges facing chemists in the area of homogeneous catalysis. The symposium
began with the keynote lecture given by G. Wilke, who is the distinguished director of
the Max Planck Institut fur Kohlenforschung (Mulheim, West Germany). The Institute
is of world renown, especially for the work of F. Fischer and C. Ziegler who both won
the Nobel Prize for their pioneering work in the area of catalysis. G. Wilke cogently
presented the basic concepts of homogeneous catalysis via metal complexes. Although
he covered a lot of material, he clearly showed how various factors can influence a
catalyst. A change in the metal, ligand, anions or reaction temperature can have a drastic
influence on the rate of reaction and the composition of the products. For each individual
topic, examples (both old and new) from his institute were given to illustrate and sub
stantiate his viewpoints.
Most of the concepts presented in the keynote lecture were reemphasized and
presented in greater detail for a variety of chemical systems throughout the symposium.
The first session was primarily concerned with the topic of selectivity. A. Nakamura
(Osaka University) described stereo-, regio-, and enatioselective control in homogeneous
catalysis. He stressed enatioselectivity of particular cobalt complexes on prachiral sub
strates and rationalized the selectivity in terms of a prochiral carbene intermediate.
Selectivity in polymer formation was discussed by P. Teyssie (University of Liege),
particularly with respect to olefm and diolefin polymerisations. After presenting the
current knowledge and concepts of olefin polymerisation mechanisms, new concepts
such as control of "chronoselectivity" in propagation reactions were introduced. Stereo
sequential distribution within a polymer could be related to change in the catalyst's
coordination sphere. Such a control means that the physical properties of the synthesized
polymers could be predetermined.
The activation of C-H and C-C bonds is normally considered to be in the domain
of heterogeneous catalysis, however papers delivered by G. Parshall (E. I. duPont de
Nemours and Company) and A. Shilov (Institute of Chemical Physics, Moscow) indicated
that such reactions can be performed with a homogeneous catalyst. Many of these reac
tions in homogeneous systems are stoichiometric rather than catalytic, but C-H and C-C
activation is nevertheless occurring.
The second session was primarily devoted to biological and asymetric catalysis.
A discussion of the biological and chemical fixation of molecular nitrogen was presented
PREFACE ix
by J. Chatt (University of Sussex). A comparison of current results of model systems with
that of nitrogenase indicates similarities which could help in understanding biological
nitrogen fixation reactions. J. Peterson (The University of Texas Health Science Center)
examined the present understanding of cytochrom 450 and possible mechanisms by
which it catalyzes the reduction of molecular oxygen. Model systems of dioxygen com
plexes of metalloporphyrins was discussed by B. R. James (University of British Columbia).
A review of recent progress in asymetric catalysis was given by P. Pino (Swiss
Federal Institute of Technology). It was indicated that presently most chemical design
and research is largely empirical in nature and the mechanism of how asymetric induc
tion originates is not yet understood. A detailed study which tries to relate the structure
of a catalyst to the chirality of the product was given by W. S. Knowles (Monsanto
Company). X-ray crystallographic investigations on a large number of asymetric rhodium
hydrogenation catalysts appear to indicate that the chirality of the product may be
dependent upon steric factors.
Metalocyclic metal complexes, especially in relationship to metathesis and possible
organometallic reaction intermediates, has recently been one of the most active fields in
chemistry. The topic was entertained by three people. K. Itoh (Toyohashi University of
Technology) related five-membered palladium metalocycles to the formation of carbon
carbon bonds from trimerization reactions of olefins. Some very interesting reactions of
thermodynamically unstable nickel and titanium metalocycles was presented by R. Grubbs
(California Institute of Technology). C. P. Casey (University of Wisconsin) favored
carbene complexes as intermediates in some olefin metathesis reactions and he gave
compelling reasons why.
A few of the talks were related to commercial processes. A review and up-date
of the current thinking in Fisher-Topsh Catalysis was given by I. Tkatchenko (Institut
de Recherches sur la Catalyse). The production of ethylene glucol from synthesis gas via
rhodium cluster catalysis has been taken very seriously by Union Carbide. J. Vidal (Union
Carbide) imparted some insight on how to stabilize the large clusters from decomposing
into smaller fragments by using an encapsulated atom to add rigidity to the cluster. R.
Ugo (Instituto di Chimica Generale e Inorganica) showed that metal clusters when put on
inorganic oxides as a support have drastically different properties which may be used to
enhance their catalytic activity.
Reaction mechanisms of catalysts are very important to ascertain, especially in
respect to designing new and better catalysts. J. Halpern (University of Chicago) looked
at this topic in great detail. He showed by mechanistic and thermodynamic considerations
that many catalytic and organometallic reactions can viably occur through radical
intermediates rather than by insertion mechanisms. E. Muetterties (University of California)
isolated and fully characterized a number of rhodium hydride complexes in order to
study their catalytic activity.
The catalytic photochemical decomposition of water to form oxygen and hydrogen
would have a major impact on the energy problem and although this is a very active area
of chemistry, only one paper was presented on this intriguing problem. H. Gray (California
Institute of Technology) discussed using bridged rhodium complexes to tackle the problem.
x PREFACE
Besides the 19 plenary lectures mentioned briefly above, and all deserving more
space than the few words allotted to them in this compendium, 7S individual papers from
14 nations were presented concomittantly on varying aspects of homogeneous catalysis.
Due to the overwhelming success of this First International Symposium on Homo
geneous Catalysis, the organizers are looking forward to a similar seminar to be held in
two years. The second symposium will be hosted by G. Wilke and will probably be held
in Dusseldorf, West Germany. Present day problems, such as the dependence upon oil
for the production of gasoline and most chemical products, will not be solved in two
years-but hopefully the initial steps in solving and reducing the obstacles of such a task
will have been made.
At the conclusion, we would like to express our sincere appreciation to Dr. Joe
Beran, the chairman of the Regional ACS meeting and other officers, Dr. Albert Olivares,
Dr. John England, Dr. Jerry Broussard on behalf of the Organizing Committee and Mrs.
Lou Carreon. I would like to also express our deep appreciation to these donors of
funds and moral support:
Allied Chemical Co. Phillips Petroleum Co.
Celanese Chemical Co. PPG Industries
Conoco Pullman Kellogg
Dow Chemical U.S.A. Shell Development Co.
E. I. duPont de Nemours & Co. Strem Chemical
EI Paso Products Co. Texas A&M University
Engelhard Industries Texas Eastman Co.
Exxon Research & Engineering Co. Union Carbide Corp.
Hoffman-La Roche
Idemitsu Petrochemical Co., Ltd.
Monsanto Chemical Co.
Olson Travel Agency
Minoru Tsutsui
Dennis Sekutowski
Contents
KEYNOTE LECTURE
Basic Concepts of Homogeneous Catalysis with Metal Complexes ....
Gunther Wilke
MECHANISM AND THEORETICAL TREATISES
Invited Papers
Free Radical Mechanisms in Homogeneous Catalysis. . . . . . . . . . . . . . 25
Jack Halpern
Selectivity Control in Homogeneous Catalysis. . . . . . . . . . . . . . . . . . . 41
Akira Nakamura
Contributed Papers
Molecular Orbital Approach to CX-1T Rearrangements of
Organotransition Metal Complexes in Catalysis. . . . . . . . . . . . 55
Kazuyuki Tatsumi and Minoru Tsutsui
Molecular Orbital Calculations of Carbonyl Compounds
ofNi and Cu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Hiroyuki Itoh and A. Barry Kunz
Hydrogen Gas Catalysis of Free Radical Decay Reactions
in Organic Solids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Malcolm Dole, J. Salik and N. Gvozdic
xi
