Catalytic Activation of Carbon Monoxide

351 Pages·1981·4.5 MB·English

by  Peter C. Ford (Eds.)

1
0
0
w
2.f
5
1
0
1-
8
9
1 Catalytic Activation
k-
b
1/
2
0
0.1 of Carbon Monoxide
1
oi:
d
1 |
8
9
1
5,
y
a
M
e:
at
D
n
o
ati
c
bli
u
P
1
0
0
w
2.f
5
1
0
1-
8
9
1
k-
b
1/
2
0
1
0.
1
oi:
d
1 |
8
9
1
5,
y
a
M
e:
at
D
n
o
ati
c
bli
u
P
Catalytic Activation
of Carbon Monoxide
Peter C. Ford, EDITOR
University of California
1
0
0
w
2.f
5
1
0
1-
8 Based on a symposium
9
1
k-
b
21/ sponsored by the Division of
0
1
0.
1
oi: Inorganic Chemistry at the
d
1 |
8
9 Second Chemical Congress of the
1
5,
y
a
M North American Continent
e:
at
D
n (180th ACS National Meeting),
o
ati
c
bli Las Vegas, Nevada,
u
P

August 25-27, 1980.
ACS SYMPOSIUM SERIES 152
AMERICAN CHEMICAL SOCIETY
WASHINGTON, D. C. 1981
1
0
0
w Library of Congress CIP Data
2.f
5 Catalytic activation of carbon monoxide.
1
1-0 (ACS symposium series, ISSN 0097-6156; 152)
98 Includes bibliographies and index.
1
k- 1. Catalysis—Congresses. 2. Carbon monoxide—
b
1/ Congresses. 3. Chemistry, Organic—Synthesis—Con
02 gresses.
0.1 I. Ford, Peter C. II. American Chemical Society.
1 Division of Inorganic Chemistry. III. Chemical Con
oi: gress of the North American Continent (2nd: 1980:
1 | d Las Vegas, Nev.). IV. Series.
98 TP156.C35C39 661'.8 81-1885
5, 1 ISBN 0-8412-0620-1 ACSMC8 152 1-35A8 A1C9R821
y
a
M
e:
at
D
n
o Copyright © 1981
ati
blic American Chemical Society
u
P All Rights Reserved. The appearance of the code at the bottom of the first page of each

article in this volume indicates the copyright owner's consent that reprographic copies of
the article may be made for personal or internal use or for the personal or internal use of
specific clients. This consent is given on the condition, however, that the copier pay the
stated per copy fee through the Copyright Clearance Center, Inc. for copying beyond that
permitted by Sections 107 or 108 of the U.S. Copyright Law. This consent does not extend
to copying or transmission by any means—graphic or electronic—for any other purpose,
such as for general distribution, for advertising or promotional purposes, for creating new
collective work, for resale, or for information storage and retrieval systems.
The citation of trade names and/or names of manufacturers in this publication is not to be
construed as an endorsement or as approval by ACS of the commercial products or services
referenced herein; nor should the mere reference herein to any drawing, specification,
chemical process, or other data be regarded as a license or as a conveyance of any right or
permission, to the holder, reader, or any other person or corporation, to manufacture, repro
duce, use, or sell any patented invention or copyrighted work that may in any way be
related thereto.
PRINTED IN THE UNITED STATES OF AMERICA
ACS Symposium Series
M. Joan Comstock, Series Editor
1
0
0
w
2.f
5
1
0
1- Advisory Board
8
9
1
k-
1/b David L. Allara James P. Lodge
2
0
1
0. Kenneth B. Bischoff Marvin Margoshes
1
oi:
1 | d Donald D. Dollberg Leon Petrakis
8
9
1
5, Robert E. Feeney Theodore Provder
y
a
M
e: Jack Halpern F. Sherwood Rowland
at
D
n Brian M. Harney Dennis Schuetzle
o
ati
c
bli W. Jeffrey Howe Davis L. Temple, Jr.
u
P

James D. Idol, Jr. Gunter Zweig
01 FOREWORD
0
w
2.f
15 The ACS SYMPOSIUM SERIES was founded in 1974 to provide
0
1- a medium for publishing symposia quickly in book form. The
8
9
1 format of the Series parallels that of the continuing ADVANCES
k-
1/b IN CHEMISTRY SERIES except that in order to save time the
02 papers are not typeset but are reproduced as they are sub
1
0. mitted by the authors in camera-ready form. Papers are re
1
oi: viewed under the supervision of the Editors with the assistance
d
1 | of the Series Advisory Board and are selected to maintain the
8
19 integrity of the symposia; however, verbatim reproductions of
y 5, previously published papers are not accepted. Both reviews
a
M and reports of research are acceptable since symposia may
ate: embrace both types of presentation.
D
n
o
ati
c
bli
u
P
PREFACE
The catalytic activation of carbon monoxide is a research area currently
receiving major attention from academic, industrial, and government
laboratories. There has been a long standing interest in this area; however,
the new attention obviously is stimulated by concerns with the present and
future costs and availability of petroleum as a feedstock for the production
of hydrocarbon fuels and of organic chemicals. One logical alternative
source to be considered is "synthesis gas," mixtures of carbon monoxide
1
0
0 and hydrogen that can be produced from coal and other carbonaceous
pr
2. materials.
5
1
0 Potential applications of synthesis gas include conversion to liquid
1-
8 fuels via the Fischer-Tropsch reaction, production of hydrogen via the
9
1
k- shift reaction (for ammonia manufacture and for the direct liquifaction
b
1/ of coal) and the production of methanol, ethylene glycol, and other
2
0
1 oxygenated organic chemicals. Efficient catalysts for such processes need
0.
oi: 1 to be designed and their fundamental reaction mechanism chemistry under
d stood. The symposium was organized to focus on these questions. The
1 |
8 major emphasis was directed toward homogeneous catalysis; however,
9
1
5, several authors addressed the question of characterizing catalysis pathways
ay on surfaces. The chapters included in this volume comprise the major part
M
e: of the papers presented and are organized in the order of presentation.
Dat The symposium was sponsored by the Inorganic Division of the American
on Chemical Society and also received some financial support from the
cati Chevron Research Company, for which the Editor is grateful.
bli
u
P

PETER C. FORD
Santa Barbara, California
November 30, 1980
ix
1
Activation of Carbon Monoxide by Carbon and
Oxygen Coordination
Lewis Acid and Proton Induced Reduction
of Carbon Monoxide
D. F. SHRIVER
Department of Chemistry, Northwestern University, Evanston, IL 60201
1
0
0
h
c
2.
5
1
0
1-
8
9
1
k-
b
1/
2
0
1
0.
1
oi:
d
1 |
8
9
1
5,
y
a In its free state, carbon monoxide is highly resistant to
M
e: attack by hydrogen and a variety of other common reducing agents.
at The reactivity of coordinated CO is much greater than that of the
D
n free molecule and metal surfaces are in general even more effec
o
ati tive than simple coordination compounds in promoting CO reduc
blic tion. One great challenge to the inorganic chemist is to make
Pu the connection between chemistry which occurs on the surfaces of
metals and the more readily studied reactions of discrete molecu
lar organometallics. One possible mode of CO activation which
has been invoked in heterogenous catalysis is C and O bonding to
a surface. This bifunctional activation of CO may lead to CO
cleavage and eventual incorporation of a surface carbide into
organic products, or to direct incorporation of the C and O coor
dinated CO into an organic group (1-3). Bifunctional activation
also is thought to be important in molecular systems (4,5), but
it is fair to say that the evidence for, and understanding of
this phenomenon has been very rudimentary. In this paper we pre
sent the results of studies at Northwestern which were designed
to provide clear-cut evidence for bifunctional CO activation in
molecular systems and to provide information on the important
0097-6156/81/0152-0001 $05.00/0
© 1981 American Chemical Society
2 CATALYTIC ACTIVATION OF CARBON MONOXIDE
chemical variables in these reactions. We first describe Lewis
acid promotion of the alkyl migration (CO insertion) reaction,
including recent results on the combination of this acid promoted
alkyl migration reaction with CO reduction. This repetitive
sequence of CO insertion and carbonyl reduction provides a means
of building hydrocarbon chains under mild conditions. Finally,
proton induced CO reduction will be described, and the most
recent mechanistic information on this reaction will be pre
sented. As a prelude to these discussions, we outline two fun
damental reactions of coordinated CO.
Electrophilic and Nucleophilic Attack of Coordinated CO
The attack on coordinated carbon monoxide by nucleophiles was
first extensively developed in synthetic organometallic chemistry
01 by E. 0. Fischer and his students (6); as discussed by others in
0
h this volume, this reaction provides one route to the reduction of
c
52. coordinated CO and to catalysis of the water gas shift reaction.
1
0 Those carbonyl groups which are susceptible to attack by nucleo
1-
8 philes are electron deficient, as judged by their high CO
9
k-1 stretcing frequencies (7).
b
1/
02 By contrast, metal carbonyls having low CO stretcing frequen
1
0. cies are susceptible to attack of the CO oxygen atom by electro-
1
oi: philes such as Al(CH3)3, AlBr3, or BF3. This chemical evidence
d and a variety of physical evidence indicate that a low CO
1 | stretching frequency corresponds to high electron density on the
8
19 CO iigand (8). Carbonyl groups in this category include bridging
5, carbonyls, terminal carbonyls in metal carbonyl anions, and ter
y
Ma minal carbonyls in donor substituted metal carbonyls, structures
e: la through lc. The attack on bridging carbonyls by electrophilic
at
D
n
o
ati 0 0 0
c
bli
u
P

C L 0 C
0 0
AIR.
3
(la) (lb)
(lc)
1. SHRIVER Lewis Acid and Proton Induced Reduction 3
reagents is a common feature of the chemistry of polynuclear
carbonyls, and it may lead to a variety of CO rearrangements
(8^,9^). One striking physical effect of Lewis acid addition to
the oxygen end of CO is a very large reduction in the CO
stretching frequency, which implies a large decrease in CO bond
order, Figure 1 (10). This phenomenon will be discussed in more
detail at the end of the paper, and for the present it will
suffice to point out that the addition of a Lewis acid to the
carbonyl oxygen favors carbene-like resonance structures, which
arise from the polarization of the 7r system, equation 2.
LM-C=0 + A1X > L^C-0^ (2)
n 3
AIX3
The very large perturbing influence of C and 0 bonding on
1
00 the CO bond order led us to explore the influence of Lewis acid
h
2.c and proton acid promoted reactions of metal carbonyl complexes.
5
1
0
1- Acid Promoted CO Insertion
8
9
1
k- Owing in part to its great commercial importance, the CO
b
1/ insertion reaction is perhaps the most thoroughly studied metal
2
10 carbonyl reaction other than substition (11-13). As shown in
10. equation 3a, the currently
doi: R
1 | I ki ki
8
9
1
5,
y
a
M accepted mechanism for this reaction is the migration of the
ate: alkyl group onto a coordinated CO, to yield a coordinatively
D unsaturated metal acyl intermediate (which perhaps may be solvent
n
o stabilized). This intermediate is then attacked by an incoming
cati ligand to produce a stable acyl complex, equation 3b. When a
bli
u
P
. R k R
9 X
v*-c; + L' ^ef v-'*-^ (3b)
0
stable product is formed, k_ « k, ttie kinetic expression takes
2 2
the form given in equation 4, with two limiting conditions,
equations 5a and 5b.
k ^ f L ' H L ^ C O )]
r a te = k. + k[L'] ( 4)
x 2
rate = Kk[Lf][LMR(C0)] when k[Lf] « k. (5a)
2 n 2 x
rate = k[LMR(C0)] when k[Lf] » k_ (5b)
1 n 2 x