Catalyst composition and process for the preparation of polymers

A catalyst composition useful in polymerizing carbon monoxide with one or more ethylenically unsaturated compounds is presented. The catalyst composition comprises a metal of Group VIII of the Periodic Table and an anion which is weakly or non-coordinating with the Group VIII metal and which includes an oxidant moiety in its molecular structure. A process for the preparation of copolymers catalyzed by this composition is also presented.

FIELD OF THE INVENTION 
The invention relates to catalysts and processes for the preparation of 
copolymers of carbon monoxide with one or more compounds comprising an 
ethylenically unsaturated bond. 
BACKGROUND OF THE INVENTION 
Linear copolymers of carbon monoxide and one or more ethylenically 
unsaturated compounds may be prepared by reacting the monomers under 
polymerization conditions with a catalyst system which comprises a Group 
VIII metal and a weakly or non-coordinating anion. The preparation of 
these copolymers may be carried out in the liquid phase. That is, the 
reaction can be conducted so that the continuous phase is formed by a 
liquid diluent such as a non-polymerizable liquid in which the catalyst 
dissolves but in which the formed copolymers are substantially insoluble. 
The recovery and purification of the product of such a process normally 
requires a filtration or centrifugation step. Moreover, a distillation 
step is usually required in order to recover pure diluent. 
The preparation of the copolymers may also proceed in the gas phase. When 
this approach is taken the continuous phase is formed by gaseous carbon 
monoxide and possibly one or more of the other monomers if they are 
present in the gas phase under the prevailing polymerization conditions. 
The gas phase preparation of the copolymers is considered advantageous 
because product recovery is simpler than in the liquid phase process. The 
separation and purification steps inherent in the liquid phase process can 
also be omitted in gas phase production. This improves the economics of 
the process. 
Considerable efforts have been made to increase the activity of the 
catalyst system. Some improvement has resulted from, for example, changing 
the reaction conditions or modifying the components participating in the 
catalyst. EP-A-239145 proposes an enhancement of catalytic activity by 
incorporating an oxidant such as a quinone in the catalyst system. Between 
about 1 and 10000 mol of quinone per gram atom of palladium are 
purportedly preferred with between about 10 and 100 mol per gram atom of 
palladium being set forth in the examples. 
EP-A-272728 proposes that other oxidants are also suitable for enhancing 
the catalyst activity such as organic nitrites and nitro compounds. 
Quantities similar to those of the quinones are recited for the use such 
other oxidants. That is, large amounts of the oxidants are required. 
Significant improvements in catalyst activity continue to be sought. 
Moreover, the art could benefit from such improvements particularly where 
the process occurs in the gas phase without large quantities of catalyst 
modifiers. Economically advantageous catalyst systems such as those which 
do not require separate or discrete additions of catalyst promoter are 
also needed. 
SUMMARY OF THE INVENTION 
A catalyst composition is presented herein comprising a metal of Group VIII 
of the Periodic Table, and an anion which is weakly or non-coordinating 
with the Group VIII metal and which includes an oxidant moiety in its 
molecular structure. 
In one embodiment, the catalyst composition comprises a cobalt 
napthoquinone sulfonate. 
This catalyst composition is particularly useful in the preparation of 
copolymers which comprises copolymerizing carbon monoxide with one or more 
ethylenically unsaturated compounds. 
In one embodiment, the process is conducted in the gas phase.

DETAILED DESCRIPTION OF THE INVENTION 
It has now been found that catalyst compositions comprising a weakly or 
non-coordinating anion which includes an oxidant moiety in its molecular 
structure increases the catalytic activity in the polymerization of carbon 
monoxide and one or more compounds having an ethylenically unsaturated 
bond well beyond catalyst activities obtained with previously used 
catalyst modifiers. This is particularly true in the case of gas phase 
polymerizations. These catalyst systems and processes do not require the 
use of a large amount of oxidant. Furthermore, polymers prepared using 
this catalyst composition and process possess a better thermal stability 
than polymers prepared using .the large amount of oxidant for enhancing 
the catalyst activity. 
The invention thus relates to a catalyst composition comprising: 
a) a metal of Group VIII of the Periodic Table, and 
b) an anion which is weakly or non-coordinating with the Group VIII metal 
and which includes an oxidant moiety in its molecular structure. 
The invention further relates to a process for the preparation of 
copolymers which comprises copolymerizing carbon monoxide with one or more 
ethylenically unsaturated compounds in the presence of a catalyst 
composition according to this invention. 
The weakly or non-coordinating anion is typically an anion derived from an 
acid with a pKa of less than 6. An anion of an acid with a pKa of less 
than 2 is preferred. The anion may contain one or more anionic groups; one 
is preferred. The weakly or non-coordinating anion is preferably an anion 
derived from a sulfonic acid or a carboxylic acid. Phosphoric acids are 
also suitable sources of the weakly or non-coordinating anion. 
The oxidant moiety may comprise an aromatic or (cyclo)aliphatic group to 
which one or more oxo, nitro or nitroso groups are attached. Suitably the 
oxidant moiety is selected from nitro groups, having groups such as 
nitrophenyl groups, 1,3-dinitrophenol groups, 4-isopropyl-1-nitrophenyl 
groups and nitropropyl groups. The corresponding weakly or 
non-coordinating anions are thus selected from 1,3-dinitrobenzenes, 
4-isopropyl-1-nitrobenzenes and nitropropanes substituted with an 
appropriate anionic group. 
Oxidant moleties from groups containing two carbonyl groups in conjugation 
with ethylenic and/or aromatic unsaturation as to form a quinone are 
preferred. 1,2- or 1,4-quinones are most preferred. In such cases the 
weakly or non-coordinating anion may be, for example, a 1,2- or 
1,4-benzoquinone; a 1,2- or 1,4-naphthaquinone; or a 1,2-, 1,4- or 
9,10-anthraquinone substituted with an appropriate anionic group. 
Anionic groups from sulfonic acids are preferred. Very good results have 
been obtained with an anion derived from 
9,10-anthraquinone-2,6-disulphonic acid, and in particular 
1,2-naphthoquinone-4-sulfonic acid, 1,4-naphthoquinone-2-sulfonic acid and 
9,10-anthraquinone-2-sulfonic acid. 
The weakly or non-coordinating anion may be incorporated in the catalyst 
composition of the invention in the form a salt, typically a cobalt salt, 
or in the form of an acid. If desired, the anion may be incorporated 
simultaneously with the Group VIII metal, e.g. as a complex in which the 
metal and the anion participate. An example is the complex Pd(CH.sub.3 
CN).sub.2 (1,2-naphthoquinone-4-sulphonate)2 which can be prepared by 
reacting palladium chloride with the silver salt of 
1,2-naphthoquinone-4sulfonic acid in acetonitrile as solvent. 
The amount of the weakly or non-coordinating anion present in the catalyst 
compositions of this invention is typically in the range of from 0.5 to 20 
mol per gram atom of Group VIII metal, preferably from 1.0 to 10 mol per 
gram atom of Group VIII metal and most preferably from 1.5 to 5 mol per 
gram atom of Group VIII metal. 
The metals of Group VIII include the noble metals ruthenium, rhodium, 
palladium, osmium, iridium and platinum as well as iron, cobalt and 
nickel. Mixtures of Group VIII metals may also be used. Among the group 
VIII metals, palladium, rhodium and nickel are preferred. Palladium is 
most preferred. 
Metal salts are ordinarily used for incorporating the Group VIII metal(s) 
in the catalyst system. A metal salt of a carboxylic acid such as acetic 
acid is preferred. 
It is also preferred that the catalyst composition comprises a ligand 
capable of complexing with the Group VIII metal via one or more atoms of 
the ligand selected from phosphorus, arsenic, antimony, sulphur and 
nitrogen atoms. 
Suitable ligands include monodentate ligands, bidentate ligands and 
polydentate ligands. Bidentate ligands, in particular those which are 
capable of complexing with the Group VIII metal via two atoms of the 
ligand selected from phosphorus, sulphur and nitrogen atoms, are 
preferred. 
Preferred nitrogen bidentates are compounds of the general formula 
##STR1## 
wherein X and Y represent organic bridging groups containing three or four 
bridging atoms, two of which are carbon atoms. Such preferred bidentates 
include, for example, 2,2'-bipyridine and 1,10-phenanthroline. 
Preferred sulphur bidentates are compounds of the general formula R.sub.1 
S-R-SR.sub.2 wherein R represents a bivalent organic bridging group 
containing at least two carbon atoms in the bridge and each of R.sub.1 and 
R.sub.2 independently represents an optionally substituted hydrocarbyl 
group, such as 1,2-bis(ethylthio)ethane and cis-1,2-bis(benzylthio)ethene. 
Preferred phosphorus bidentates are compounds of the general formula 
EQU R.sup.1 R.sup.2 P-R-PR.sup.3 R.sup.4 (II) 
wherein R has the previously established meaning and each of R.sub.1, 
R.sub.2, R.sub.3 and R.sub.4 independently represents a substituted or 
non-substituted hydrocarbyl group. R.sub.1, R.sub.2, R.sub.3 and R.sub.4 
may be the same or different, optionally substituted, aliphatic, 
cycloaliphatic or aromatic groups. Aromatic groups substituted by one or 
more polar groups are preferred. Compounds of formula (II) wherein each of 
R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represents a phenyl group comprising 
an alkoxy group containing up to 4 carbon atoms at one or both 
orthopositions with respect to the phosphorus atom to which the phenyl 
group is linked are especially preferred. 
Examples of suitable phosphorus containing bidentate ligands are 1,2-bis 
(diphenylphosphino) ethane, 1,3-bis (diphenylphosphino)-propane, 
1,3-bis[bis(2-methoxyphenyl)phosphino]propane and 1,3-bis[bis (2, 
6-dimethoxyphenyl) phosphino]propane. 
In general, it is preferred that the bidentate ligand be present in the 
catalyst system in the range of between about 0.5 to 100 mol per gram atom 
of Group VIII metal. It is even more preferred that the bidentate ligand 
is present in a range of between about 1 to 50 mol per gram atom of Group 
VIII metal. However, if the catalyst system comprises a phosphorus 
bidentate ligand of formula (II), the preferred amount of ligand is then 
in the range of about 0.5 to 2.0 and more preferably in the range of about 
0.75 to 1.5 mol per gram atom of Group VIII metal. 
When the process of this invention is carried out as a gas phase process 
the catalyst composition is best used as a supported catalyst. That is, 
the catalyst composition is deposited on a support or carrier material. 
The support may be inorganic such as silica, alumina, talc or charcoal. 
Alternatively organic supports may be used such as cellulose, dextrose or 
dextran gel. Supports which are substantially comprised of a porous 
material are preferred such as a carrier material having a pore volume of 
at least 0.01 cm.sup.3 per gram as determined by mercury porosimetry. 
Polymeric materials such as polyethylene, polypropylene, polyoxymethylene 
and polystyrene comprise some very suitable supports. Mixed materials such 
as polymer impregnated silicas may also be used. 
A preferred carrier material is a linear alternating copolymer of carbon 
monoxide with one or more ethylenically unsaturated compounds. A copolymer 
which as regards structure and composition is substantially the same as 
the copolymer to be prepared in the process of the invention is a most 
preferred carrier. 
The preparation of the catalyst system may conveniently be carried out in a 
separate step preceding the process of the invention, e.g. by combining 
the catalyst components. Impregnating the carrier material with a solution 
or suspension of the catalyst components or precursors thereof can also be 
conducted to prepare the catalyst system. Further, the various catalyst 
components may be added to the carrier material together or separately. 
Ethylenically unsaturated compounds which can be used as starting materials 
in the copolymerization process of the invention include compounds 
consisting exclusively of carbon and hydrogen. Compounds which also 
comprise one or more hetero-atoms such as unsaturated esters may also be 
used as starting materials. Unsaturated hydrocarbons are preferred 
ethylenically unsaturated compounds. Examples include lower olefins such 
as ethene, propene and 1-butene, cyclic compounds such as cyclopentene and 
aromatic compounds such as styrene and alpha-methylstyrene. Ethene, 
propene or a mixture of ethene and propene are the most preferred 
ethylenically unsaturated compounds. 
The molar ratio between the monomers (ie., carbon monoxide and the 
ethylenically unsaturated compound(s)) is generally in the range of about 
5:1 to 1:5. Preferably the molar ratio is in the range of about 2:1 to 
1:2, for example when the monomers are in substantially equimolar amounts. 
When the process of this invention is carried out as a gas phase process it 
is preferably carried out with addition of a small quantity of a volatile 
protic liquid such as a lower aliphatic alcohol. Such alcohols typically 
have up to 4 carbon atoms and/or hydrogen. The quantity of this liquid is 
sufficiently small so that under the polymerization conditions the liquid 
is substantially in the gas phase. A suitable quantity may be 40-60% by 
weight, relative to the quantity which is sufficient to saturate the gas 
cap under the conditions of the polymerization. 
When the copolymerization process is carried out as a liquid phase process 
a diluent is preferably used in which the catalyst composition is soluble 
and in which the formed copolymer product is substantially insoluble. 
Preferred diluents are volatile protic liquids comprising a lower alcohol 
having up to 4 carbon atoms. Methanol is a most preferred diluent. 
The preparation of the copolymers is preferably carried out at a 
temperature in the range of between about 20.degree. to 200.degree. C., 
although the use of a reaction temperature outside that range is not 
precluded. The most preferred reaction temperature is between about 
25.degree. to 150.degree. C. Suitable pressures generally are within the 
range of about 1 to 200 bar, but preferably the pressure is in the range 
of about 2 to 150 bar. 
The quantity of catalyst used in the process of this invention can vary 
within wide limits. Per mol of ethylenically unsaturated compound to be 
polymerized, a quantity of catalyst is preferably used which contains 
10.sup.--7 -10.sup.--3 and in particular 10.sup.-6 -10.sup.-4 gram atom 
Group VIII metal. 
The copolymers obtained according to the invention can be processed into 
shaped articles, films, sheets, fibers and the like. They exhibit good 
mechanical properties and are hence suitable for a variety of commercially 
interesting applications. Such applications include, for example, 
automobile parts and packaging materials for food and drinks. 
The invention will be further illustrated by the following examples. In 
each example, C.sup.13 -NMR analysis established that the carbon 
monoxide/ethene copolymers prepared had linear chains in which the units 
originating from carbon monoxide were alternating with the units 
originating from ethene. 
EXAMPLE 1 (COMATIVE) 
A carbon monoxide/ethene copolymer was prepared as follows. 
A catalyst was prepared by absorbing a catalyst solution containing 0.25 ml 
tetrahydrofuran, 3.75 ml methanol, 0.01 mmol palladium acetate, 0,011 mmol 
1,3-bis[bis(2-methoxyphenyl) phosphino]propane and 0.05 mmol 
p-toluenesulphonic acid on 8 g of a linear alternating terpolymer of 
carbon monoxide with ethene and propene. 
The catalyst thus prepared was introduced into a 500-ml autoclave provided 
with a mechanical stirrer. After the autoclave was closed and the air 
therein was replaced by 1 bar carbon monoxide, 20 bar carbon monoxide was 
forced in, followed by 20 bar ethene. The autoclave contents were brought 
to a temperature of 90.degree. C. and the pressure was maintained by 
forcing in a 1:1 (v/v) carbon monoxide/ethene mixture. After 5 hours the 
polymerization was terminated by releasing the pressure and cooling the 
reaction mixture to room temperature. 
The polymerization rate was calculated from the consumption of the carbon 
monoxide/ethene mixture used to maintain the pressure. The rate found 
after 1 hour polymerization time (an approximation of the initial rate), 
the rate found after 4 hours and the average rate over the entire period 
of 5 hours have been given in Table I. The quantity of copolymer obtained 
was in agreement with the average polymerization rate. 
EXAMPLES 2-7 
Carbon monoxide/ethene copolymers were prepared in substantially the same 
way as in Example 1, but with the difference that 0.05 mmol of one of the 
sulfonic acids or cobalt sulphonates mentioned in Table I were used, 
instead of p-toluenesulphonic acid. 
The polymerization rates were as indicated in Table I. The quantities of 
the copolymers obtained were in agreement with the average polymerization 
rates. 
These examples illustrate that catalysts made according to the instant 
invention display significantly greater activity than has been previously 
seen. 
EXAMPLES 8 AND 9 (COMATIVE) 
Carbon monoxide/ethene copolymers were prepared in substantially the same 
way as in Example 1, but with the difference that the catalyst solution 
contained, as an additional compound, 1,4-naphthoquinone. The quantity of 
1,4-naphthoquinone was 0.05 mmol in Example 8 and 0.5 mmol in Example 9. 
The polymerization rates were as indicated in Table I. The quantities of 
the copolymers obtained were in agreement with the average polymerization 
rates. 
TABLE I 
______________________________________ 
Polymerization rates 
(kg copolymer/g Pd .multidot. h) 
Sulfonic acid or 
After After Average 
Example 
cobalt sulphonate 
1 h 4 h over 5 h 
______________________________________ 
1.sup.1) 
p-toluenesulphonic acid 
1.8 1.8 1.8 
2 1,2-naphthoquinone-4- 
8.2 14.5 10.7 
sulfonic acid 
3 9,10-anthraquinone-2- 
6.4 16.6 10.4 
sulfonic acid 
4 cobalt 1,2-naphtho- 
15.3 15.9 15.1 
quinone-4-sulphonate 
5 cobalt 1,4-naphtho- 
12.3 12.3 12.3 
quinone-2-sulphonate 
6 cobalt 9,10-anthra- 
4.8 8.0 5.9 
quinone-2-sulphonate 
7 cobalt 9,10-anthra- 
4.5 4.5 4.2 
quinone-2,6-disulphonate 
8.sup.1,2) 
p-toluenesulphonic acid 
2.3 2.3 2.3 
9.sup.1,3) 
p-toluenesulphonic acid 
2.9 2.9 2.9 
______________________________________ 
.sup.1) for comparison; not according to the invention 
.sup.2) 0.05 mmol naphthoquinone was present 
.sup.3) 0.5 mmol naphthoquinone was present 
EXAMPLE 10 (COMATIVE) 
A carbon monoxide/ethene copolymer was prepared as follows. A 300-ml 
autoclave provided with a mechanical stirrer was charged with 130 ml 
methanol and 2.7 g of a linear alternating terpolymer of carbon monoxide 
with ethene and propene. A catalyst solution prepared by combining 0.13 ml 
tetrahydrofuran, 0.88 ml methanol, 0.005 mmol palladium acetate, 0.0055 
mmol 1,3-bis[bis(2-methoxyphenyl)phosphino]propane and 0.025 mmol 
p-toluenesulphonic acid was added. 
After the autoclave was closed and the air therein was replaced by 1 bar 
carbon monoxide, 25 bar carbon monoxide was forced in, followed by 25 bar 
ethene. The autoclave contents were brought to a temperature of 85.degree. 
C. and the pressure was maintained by forcing in a 1:1 (v/v) carbon 
monoxide/ethene mixture. After 2.5 hours the polymerization was terminated 
by releasing the pressure and cooling the reaction mixture to room 
temperature. The copolymer was filtered off, washed with methanol and 
dried at 70.degree. C. 
Eleven (11) g of copolymer was obtained, from which an average 
polymerization rate of 6 kg copolymer/(g Pd.hour) was calculated. 
EXAMPLE 11 
A carbon monoxide/ethene copolymer was prepared in substantially the same 
way as in Example 11, but with the difference that 0.025 mmol of 
1,2-naphthoquinone-4-sulfonic acid was used, instead of p-toluenesulphonic 
acid. 
20 g of copolymer was obtained. The average polymerization rate was 13 kg 
copolymer/(g Pd.hour). 
This example further illustrates the improved activity with the catalyst 
system of the instant invention.