Polymerization of CO/olefin with phosphorus bidentate ligand-solid support reaction product

An improved process for the production of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon employs a novel catalyst composition formed from a compound of palladium, an anion of a strong non-hydrohalogenic acid and a supported bidentate ligand of phosphorus. The improved process is characterized by a reduced level of reactor fouling. The polymer products are useful as engineering thermoplastics.

FIELD OF THE INVENTION 
The present invention relates to an improved process for the production of 
a linear alternating polymer of carbon monoxide and at least one 
ethylenically unsaturated hydrocarbon. More particularly, the invention 
relates to a process for the production of such polymers which employs a 
novel catalyst composition formed from, inter alia, a supported bidentate 
ligand of phosphorous. The invention also relates to certain novel 
precursors of the catalyst compositions. 
BACKGROUND OF THE INVENTION 
The class of polymers of carbon monoxide and olefin(s) has been known for 
some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of 
relatively low carbon monoxide content in the presence of free radical 
initiators, e.g., peroxy compounds. G.B. 1,081,304 produced compounds of 
higher carbon monoxide content in the presence of alkylphosphine complexes 
of palladium salts as catalysts. Nozaki extended the reaction to produce 
linear alternating polymers in the presence of arylphosphine complexes of 
palladium moieties and certain inert solvents. See, for example, U.S. Pat. 
No. 3,694,412. 
More recently, the class of linear alternating polymers of carbon monoxide 
and at least one ethylenically unsaturated hydrocarbon has become of 
greater interest in part because of the greater availability of the 
polymers. The more recent processes for the production of such linear 
alternating polymers, also known as polyketones or polyketone polymers, 
are illustrated by a number of published European Patent Applications 
including 121,965, 181,014, 213,671 and 257,663. The processes generally 
involve the use of a catalyst composition formed from a compound of 
palladium, cobalt or nickel, a strong non-hydrohalogenic acid and a 
bidentate ligand of phosphorus, arsenic, antimony or nitrogen. The scope 
of the polymerization process is extensive but, without wishing to be 
limited, a preferred catalyst composition is formed from a compound of 
palladium, a non-hydrohalogenic acid having a pKa below 2 and a bidentate 
ligand of phosphorus. 
The polymerization process whereby the linear alternating polymers are 
produced will typically provide a polymeric product which is substantially 
insoluble in the media of its production. In this as in many if not most 
polymerization processes producing insoluble product, some degree of 
reactor fouling takes place. This problem is reduced by the conventional 
procedures such as polishing the internal surfaces of the reactor or 
coating the surfaces with materials such as Teflon.RTM.. In copending U.S. 
patent application Ser. No. 338,246, filed Apr. 14, 1989, now U.S. Pat. 
No. 4,940,776 the degree of reactor fouling is reduced by incorporating in 
the reaction mixture a solid material including inorganic solids as well 
as preformed linear alternating polymer. It has also been proposed to add 
sulfonated polymeric solids to the reaction mixture as an acid component, 
e.g., U.S. patent application Ser. No. 908,899, filed Sept. 18, 1986, now 
U.S. Pat. No. 4,835,250 and other solids as a catalyst carrier for gas 
phase polymerization in U.S. patent application Ser. No. 053,780, filed 
May 26, 1987, now U.S. Pat. No. 4,778,876. It would be of advantage, 
however, to provide a polymerization process of producing linear 
alternating polymers whereby the extent of reactor fouling is reduced 
beyond that which would result from the mere presence of solid material in 
the polymerization mixture. 
SUMMARY OF THE INVENTION 
The present invention provides an improved process for the production of 
linear alternating polymers of carbon monoxide and at least one 
ethylenically unsaturated hydrocarbon which exhibits a reduced degree of 
reactor fouling. More particularly, the invention provides an improved 
process which employs a catalyst composition formed from, inter alia, a 
supported bidentate ligand of phosphorus. The invention further relates to 
novel bidentate ligands of phosphorus and to the novel catalyst 
compositions formed therefrom. 
DESCRIPTION OF THE INVENTION 
In the process of the invention there is employed a catalyst composition 
formed from a compound of palladium, a non-hydrohalogenic acid having a 
pKa below 2 and a supported bidentate ligand of phosphorus. The process 
provides an efficient method for the production of linear alternating 
polymers of carbon monoxide and at least one ethylenically unsaturated 
hydrocarbon in which a reduced degree of reactor fouling is observed. 
The ethylenically unsaturated hydrocarbons which are useful as precursors 
of the polyketone polymers have up to 20 carbon atoms inclusive, 
preferably up to 10 carbon atoms inclusive, and are aliphatic including 
ethylene and other .alpha.-olefins such as propylene, 1-butene, 
isobutylene, 1-hexene, 1-octene and 1-dodecene, or are arylaliphatic 
containing an aryl substituent on an otherwise aliphatic molecule, 
particularly an aryl substituent on a carbon atom of the ethylenic 
unsaturation. Illustrative of this latter class of ethylenically 
unsaturated hydrocarbons are styrene, p-methylstyrene, p-ethylstyrene and 
m-isopropylstyrene. The preferred linear alternating polymers are 
copolymers of carbon monoxide and ethylene or terpolymers of carbon 
monoxide, ethylene and a second ethylenically unsaturated hydrocarbon of 
at least 3 carbon atoms, particularly an .alpha.-olefin such as propylene. 
The structure of the polyketone polymers is that of a linear alternating 
polymer and the polymer will contain substantially one molecule of carbon 
monoxide for each molecule of ethylenically unsaturated hydrocarbon. When 
the preferred terpolymers are produced there will be at least about 2 
units incorporating a moiety of ethylene for each unit incorporating a 
moiety of the second hydrocarbon. Preferably, there will be from about 10 
units to about 100 units incorporating a moiety of ethylene for each unit 
incorporating a moiety of the second hydrocarbon. The polymer chain of the 
preferred polyketone polymers is therefore represented by the repeating 
formula 
EQU --CO--CH.sub.2 --CH.sub.2)].sub.x [CO--G)].sub.y (I) 
wherein G is a moiety of an ethylenically unsaturated hydrocarbon of at 
least 3 carbon atoms polymerized through the ethylenic unsaturation 
thereof and the ratio fo y:x is no more than about 0.5. When the preferred 
copolymers are produced there will be no second hydrocarbon present and 
the copolymers are represented by the above formula I where y is zero. 
When the preferred terpolymers are produced the --CO--CH.sub.2 CH.sub.2 -- 
units and the --CO--G-- units are found randomly throughout the polymer 
and the preferred ratio of y:x is from about 0.01 to about 0.1. The end 
groups or "caps" of the polymer will depend on what materials were present 
during the polymerization and whether and how the polymer has been 
purified. The precise properties of the polymer do not depend to any 
substantial extent upon the particular end groups, however, so that the 
polymer is fairly represented by the formula for the polymeric chain as 
depicted above. 
Of particular interest are the polyketone polymers of number average 
molecular weight from about 1000 to about 200,000, particularly those of 
number average molecular weight from about 20,000 to about 90,000 as 
determined by gel permeation chromatography. The physical properties of 
the polymer will depend in part on the molecular weight, whether the 
polymer is a copolymer or a terpolymer and, in the case of terpolymers, 
the nature of and the proportion of the second hydrocarbon present. 
Typical melting points for the polymers are from about 175.degree. C. to 
about 300.degree. C., particularly from about 210.degree. C. to about 
270.degree. C. The polymers will have a limiting viscosity number (LVN), 
measured in a standard capillary viscosity measuring device in m-cresol at 
60.degree. C., of from about 0.5 dl/g to about 10 dl/g, preferably from 
about 0.8 dl/g to about 4 dl/g. 
The catalyst composition to be utilized in the process of the invention is 
formed from a compound of palladium, an anion of a non-hydrohalogenic acid 
having a pKa (measured in water at 18.degree. C.) below 2 and the 
supported bidentate ligand of phosphorus. The palladium compound precursor 
of the catalyst composition is preferably a palladium alkanoate and 
palladium acetate, palladium propionate, palladium hexanoate and palladium 
octanoate are satisfactory. Palladium acetate is particularly preferred. 
The anion to be employed is the anion of an inorganic acid such as 
sulfuric acid or perchloric acid or the anion of an organic acid such as a 
carboxylic acid, including trichloroacetic acid, dichloroacetic acid or 
trifluoroacetic acid, or a sulfonic acid such as methanesulfonic acid, 
trifluoromethanesulfonic acid or p-toluenesulfonic acid. The anions of 
trifluoroacetic acid and p-toluenesulfonic acid constitute a preferred 
class of anions from which the catalyst compositions of the invention are 
formed. The anion is preferably provided as the free acid but may 
alternatively be provided as a metal salt, particularly a non-noble 
transition metal salt such as the copper salt or the nickel salt. In yet 
another modification the anion and the palladium are provided as a single 
compound, e.g., palladium trifluoroacetate. However provided, the quantity 
of anion to be utilized is from about 1 mol to about 100 mols per mol of 
palladium. Preferably the quantity of anion should be from about 2 mols to 
about 50 mols of anion per mol of palladium. 
The supported bidentate ligand of phosphorus is the reaction product of a 
solid support, organic or inorganic, containing a reactive group on the 
surface thereof which will react with a group, other than the phosphorus 
atoms, of the bidentate phosphorus ligand whose support is desired. A wide 
variety of such solid supports are satisfactory but preferred supports 
include supports having 
a) carbonyl groups, as illustrated by preformed linear alternating polymers 
of carbon monoxide and ethylenically unsaturated hydrocarbon, particularly 
linear alternating polymers of carbon monoxide and ethylene, 
b) hydroxyl groups such as silica, alumina and hydrogenated carbon 
monoxide/ethylenically unsaturated hydrocarbon polymers in which at least 
a portion of the carbonyl groups have been converted to hydroxyl, 
c) carboxylic acid groups such as copolymers of ethylene with acrylic acid 
or methacrylic acid, 
d) halogen groups such as chloromethyl-substituted polystyrenes and 
reaction products of silica with (2-chloroethyl)triethoxysilane, and 
e) isocyanate groups such as poly[methylene(polyphenylisocyanate)]. Such 
solid supports are known materials or are produced by known methods and a 
number of the supports are commercial. In part for reasons of convenience, 
the hydroxyl group-containing supports are particularly preferred, 
especially silica. 
The bidentate ligands of phosphorus are ligands which contain, in addition 
to the two phosphorus atoms, a group which is reactive with the support on 
which the ligand is to be supported. Illustrative of such bidentate 
phosphorus ligands are ligands which contain 
i) hydroxyl groups such as 
2-hydroxy-1,3-bis[di(2-methoxyphenyl)phosphino]propane, and 
ii) trialkoxysilyl groups such as the reaction product of 
2-hydroxy-1,3-bis[di(2-methoxyphenyl)phosphino]propane with 
(3-isocyanatopropyl)triethoxysilane. 
The ligands of type i) are novel materials but are produced by reaction of 
an alkali metal di(alkoxyphenyl)phosphide with epichlorohydrin. Preferred 
alkoxyphenylphosphides are those wherein each alkoxy has up to 4 carbon 
atoms and at least one alkoxy is located on a phenyl ring carbon atom 
ortho to the carbon atom through which the phenyl ring is connected to the 
phosphorus. Phosphides of lithium, sodium, potassium, rubidium or cesium 
are suitable although sodium di(alkoxyphenyl)phosphides are preferred. To 
form the hydroxy-substituted diphosphine, the appropriately substituted 
trialkoxyphosphine is reacted with alkali metal in liquid ammonia at 
reduced temperatures and the resulting phosphide is reacted with 
epichlorohydrin at moderate temperatures to produce the 
hydroxy-substituted diphosphine. 
The preferred bidentate phosphorus ligands, however, are those of type ii) 
which are produced by reacting the 
2-hydroxy-1,3-bis[di(alkoxyphenyl)phosphino]propane with an 
(isocyanatoalkyl)trialkoxysilane wherein each alkyl has up to 4 carbon 
atoms inclusive, e.g., (3-isocyanatopropyl)triethoxysilane. 
The preferred supported bidentate phosphorus ligands are produced by 
reacting this silane-containing product with a hydroxyl-containing support 
such as silica. Whatever the particular nature of the supported bidentate 
phosphorus ligand, sufficient ligand is employed to provide from about 1 
mol to about 10 mols of phosphorus per mol of palladium, preferably from 
about 2 mols to about 5 mols of phosphorus per mol of palladium. 
It is useful on occasion, but not required, to enhance the activity of the 
catalyst composition by the inclusion in the mixture from which the 
catalyst composition is formed an amount of a quinone. The preferred 
quinones are 1,4-quinones and 1,4-benzoquinone, 1,4-naphthoquinone and 
1,4-anthraquinone are satisfactory. The class of 1,4-benzoquinone and 
1,4-naphthoquinone is preferred. The presence of quinone in the catalyst 
composition mixture is not required and amounts of quinone up to about 
5000 mols of quinone per mol of palladium are suitable. When quinone is 
present, amounts of quinone from about 5 mols to about 1000 mols of 
quinone per mol of palladium are preferred. 
The polymerization process is conducted by contacting in a suitable reactor 
the carbon monoxide and ethylenically unsaturated hydrocarbon reactants 
and a catalytic quantity of the catalyst composition in a liquid reaction 
diluent under polymerization conditions. Alkanol reaction diluents such as 
ethanol and methanol are satisfactory with methanol being preferred. 
Sufficient catalyst composition is employed to provide from about 
1.times.10.sup.-7 mol to about 1.times.10.sup.-3 mol of palladium per mol 
of ethylenically unsaturated hydrocarbon to be polymerized. Preferred 
quantities of catalyst composition provide from about 1.times.10.sup.-6 
mol to about 1.times.10.sup.-3 mol of palladium per mol of ethylenically 
unsaturated hydrocarbon to be polymerized. The molar ratio of carbon 
monoxide to ethylenically unsaturated hydrocarbon is from about 5:1 to 
about 1:10, preferably from about 2:1 to about 1:5. The polymerization 
conditions include a reaction temperature from about 40.degree. C. to 
about 120.degree. C. although reaction temperatures from about 50.degree. 
C. to about 100.degree. C. are more frequent. Typical reaction pressures 
are from about 20 bar to about 150 bar, preferably from about 30 bar to 
about 100 bar. The contact of reactants and catalyst composition is 
facilitated by the provision of conventional agitation means such as 
shaking or stirring. Subsequent to polymerization, the reaction is 
terminated as by cooling the reaction mixture and releasing the pressure. 
The linear alternating polymer product is obtained as a material 
substantially insoluble in the medium of its production and is recovered 
by conventional methods such as filtration or decantation. The presence of 
small amounts of catalyst composition residue, including the ligand 
support, is not overly detrimental and in most instances the polymer is 
used as obtained. If desired, however, the polymer is purified by a 
solvent or complexing agent selective for the catalyst residues or by 
other conventional methods. 
The polyketone polymers are thermoplastics of relatively high molecular 
weight and are useful as engineering thermoplastics. They are processed by 
methods conventionally employed with thermoplastics, such as extrusion, 
injection molding and thermoforming, into a wide variety of shaped 
articles of established utility. Specific applications include the 
production of containers for food and drink and the production of parts 
and housings for automotive applications. The improved process of the 
invention is characterized by a reduced degree of reactor fouling, thereby 
providing an enhanced efficiency of polymer production.

The invention is further illustrated by the following Comparative Examples 
(not of the invention) and the following Illustrative Embodiments which 
should not be regarded as limiting. The copolymer products of Comparative 
Example I and II and of Illustrative Embodiments IV, VI and VIII were 
examined by .sup.13 C-NMR analysis. Each copolymer was found to be linear 
with alternating moieties derived from carbon monoxide and ethylene. 
COMATIVE EXAMPLE I 
A copolymer of carbon monoxide and ethylene was produced by charging 180 ml 
of methanol to an autoclave of 300 ml capacity equipped with a mechanical 
stirrer. The contents of the autoclave were warmed to 90.degree. C. and an 
equimolar mixture of carbon monoxide and ethylene was added until a 
pressure of 55 bar was reached. A catalyst composition solution was then 
added which comprised 24.5 ml methanol, 1.5 ml toluene, 0.01 mmol 
palladium acetate, 0.011 mmol 
2-hydroxy-1,3-bis[di(2-methoxyphenyl)phosphino]propane, 0.2 mmol 
trifluoroacetic acid and 2.0 mmol 1,4-naphthoquinone. The pressure inside 
the autoclave was maintained by addition of an equimolar mixture of carbon 
monoxide and ethylene. After 4.98 hours the polymerization was terminated 
by cooling the reactor and contents to room temperature and releasing the 
pressure. 
The resulting polymer suspension contained 4.98 g of copolymer and 19.90 g 
of copolymer remained on the internal surfaces of the autoclave. The 
reactor fouling was therefore calculated to be 80%. The rate of 
polymerization based on total copolymer was calculated to be 4.7 kg of 
copolymer/g Pd hr. 
ILLUSTRATIVE EMBODIMENT I 
The compound 2-hydroxy-1,3-bis[di(2-methoxyphenyl)phosphino]propane was 
produced in a reactor equipped with a mechanical stirrer. While the 
reactor was maintained at -45.degree. C., a mixture of 101.2 g 
tri(methoxyphenyl)phosphine and 1100 ml of liquid ammonia and 13.1 g of 
sodium was introduced. After 4 hours, 15.3 g of ammonium chloride, 50 ml 
of tetrahydrofuran and a solution of 13.2 g of epichlorohydrin in 200 ml 
of tetrahydrofuran were sequentially added. The ammonia was then 
evaporated and the mixture was heated to 45.degree. C. for 0.75 hour. The 
mixture was then cooled to 20.degree. C. and 105 ml of water was added and 
an aqueous layer and a tetrahydrofuran layer were formed. The 
tetrahydrofuran layer was evaporated to remove solvent and methoxybenzene. 
The residue was extracted with dichloromethane and the solvent evaporated 
from the extract. The remaining white solid was washed with methanol and 
dried. The resulting product, 
2-hydroxy-1,3-bis[di(2-methoxyphenyl)phosphino]propane was obtained in a 
71% yield based on the tri(methoxyphenyl)phosphine. 
ILLUSTRATIVE EMBODIMENT II 
A supported phosphorus bidentate ligand was produced by refluxing for 12 
hours a mixture of 5.49 g of 
2-hydroxy-1,3-bis[di(2-methoxyphenyl)phosphino]propane prepared according 
to the procedure of Illustrative Embodiment I, 2.47 g of 
(3-isocyanatopropyl)triethoxysilane and 100 ml of p-xylene. After addition 
of 38.56 g of silica, the mixture was refluxed for an additional 12 hours. 
The resulting supported bidentate phosphorus ligand was recovered by 
filtration, washed with p-xylene and dried. 
ILLUSTRATIVE EMBODIMENT III 
A solid palladium/phosphorus bidentate ligand was produced by stirring for 
16 hours at room temperature a mixture of 5.15 g of a supported phosphorus 
bidentate ligand prepared by the procedure of Illustrative Embodiment II, 
37 g of palladium acetate and 50 ml of methanol. The resulting 
palladium/phosphorus bidentate ligand composition was recovered by 
filtration and dried. The composition contained 4.33 mg of palladium/g of 
composition. 
ILLUSTRATIVE EMBODIMENT IV 
A copolymer of carbon monoxide and ethylene was produced by charging to an 
autoclave of 300 ml capacity equipped with a mechanical stirrer 220 ml of 
methanol, 439 g of a palladium/phosphorus bidentate ligand prepared by the 
procedure of Illustrative Embodiment III and 0.039 mmol of trifluoroacetic 
acid. The contents of the autoclave were heated to 90.degree. C. and an 
equimolar mixture of carbon monoxide and ethylene was added until a 
pressure of 55 bar was reached. The pressure within the autoclave was 
maintained by addition of the equimolar mixture. After 5.52 hours the 
polymerization was terminated by cooling the autoclave and contents to 
room temperature and releasing the pressure. The resulting polymer 
suspension contained 10.44 g of copolymer and 0.10 g of copolymer remained 
on the internal surfaces of the autoclave. The reactor fouling was 0.9% 
and the copolymer was obtained at the rate of 1.0 kg of copolymer/g Pd hr. 
ILLUSTRATIVE EMBODIMENT V 
A catalyst composition was produced by stirring for 16 hours at room 
temperature a mixture of 2 g of a supported phosphorus bidentate ligand 
prepared by the procedure of Illustrative Embodiment II, 166 mg of 
palladium trifluoroacetate and 25 ml of tetrahydrofuran. The resulting 
solid catalyst composition was recovered by filtration, washed with 
tetrahydrofuran and dried. The catalyst composition contained 12.5 mg of 
palladium/g of composition. 
ILLUSTRATIVE EMBODIMENT VI 
A copolymer of carbon monoxide and ethylene was produced by a procedure 
substantially similar to that of Illustrative Embodiment IV except that 
154 mg of catalyst composition produced by the procedure of Illustrative 
Embodiment V was charged to the autoclave instead of the 
palladium/bidentate phosphorus ligand composition and trifluoroacetic 
acid, and the reaction time was 18.8 hours instead of 5.52 hours. The 
resulting polymer suspension contained 21.2 g of copolymer and 0.65 g of 
copolymer remained on the internal surfaces of the autoclave. The 
polymerization rate was 0.61 kg of copolymer/g Pd hr and the reactor 
fouling was 3%. 
ILLUSTRATIVE EMBODIMENT VII 
A catalyst composition was produced by a procedure substantially similar to 
that of Illustrative Embodiment V except that 112 mg of palladium acetate 
and 170 mg of trifluoroacetic acid were employed instead of palladium 
trifluoroacetate. The catalyst composition contained 13.5 g of palladium/g 
of composition. 
ILLUSTRATIVE EMBODIMENT VIII 
A copolymer of carbon monoxide and ethylene was produced by a procedure 
substantially similar to that of Illustrative Embodiment IV except that 
64.5 g of a catalyst composition prepared by the procedure of Illustrative 
Embodiment II was introduced into the autoclave instead of the 
palladium/phosphorus bidentate ligand composition and trifluoroacetic 
acid, and the reaction time was 24.2 hours instead of 5.52 hours. The 
resulting polymer suspension contained 9.3 g of copolymer and 0.2 g of 
copolymer remained on the internal surfaces of the autoclave. The reactor 
fouling was 2% and the polymerization rate was 0.39 kg of copolymer/g Pd 
hr. 
COMATIVE EXAMPLE II 
A copolymer of carbon monoxide and ethylene was produced by a procedure 
substantially similar to that of Comparative Example I except that the 
autoclave additionally contained 155 mg of the silica employed as a 
starting material in Illustrative Embodiment I but no 1,4-naphthoquinone, 
and the reaction time was 3.2 hours instead of 4.98 hours. The resulting 
polymer suspension contained 5.74 g of copolymer and 4.16 g of copolymer 
remained on the internal surfaces of the autoclave. The polymerization 
rate was 2.91 g of copolymer/g Pd hr and the reactor fouling was 42%.