MXPA97010001A - Catalyst composition and process for the preparation of copolymers of carbon monoxide and a compound olefinically insatur - Google Patents

Abstract

A catalyst composition which is based on (a) a source of nickel cations, and (b) a bidentate binder of the general formula (I): RûRýMû-R-MýRüR4 wherein Mûy Mýrepresentan independently phosphorus, nitrogen, arsenic or antimony, Rû , RýRüy R4 independently represent groups of optionally substituted hydrocarbyls on the understanding that at least one of Rû, Rý, Rüy R 4 represents a substituted aryl group, and R represents a bivalent expansive group in which the bridge consists of more than two expansive atoms , and a process for the preparation of carbon monoxide copolymers and an olefinically unsaturated compound comprising the contact of the numbers in the presence of the catalyzed composition

Description

CATALYST COMPOSITION * AND PROCESS FOR THE PREPARATION OF COPOLYMERS OF CARBON MONOXIDE AND COMPOUND ON OLEFINICALLY INSECTED The invention relates to a catalyst composition and a process for the preparation of carbon monoxide copolymers of one or more olefinically unsaturated compounds. Linear copolymers of carbon monoxide with one or more olefinically unsaturated compounds can be prepared by contacting the monomers in the presence of a Group VIII metal-containing catalyst. The copolymers can be processed by conventional techniques in films, sheets, sheets, fibers and articles formed for domestic use and for parts in the automotive industry. They are eminently suitable for use in many exteriors for thermoplastics. In the copolymers in question the units originating from carbon monoxide or otherwise and the units originating from the compound (s) olefinically unsaturated or otherwise given in an alternating or substantially alternating arrangement. Therefore, the preparation of copolymers using palladium-based catalysts such as Group VIII of REF: 26332 metals have been studied extensively because the palladium-based catalyst provides a high polymerization ratio. However, one disadvantage of using palladium-based catalysts is the high price of palladium. This high price is accepted as an issue, in fact because it is caused by the limited natural availability of this metal. Methods are available for the extraction of palladium residues from copolymers which allow the recycling of palladium, but these methods introduce additional process steps in which they complicate the overall scheme of the polymerization process. Another disadvantage is that the palladium-based catalysts have a tendency to be coated, ie to become the zero valent metal state. The coating during the development of the copolymer and further processing may cause some gray discoloration of the copolymer, in particular when its permanent catalyst content is high. The coating may also occur during the catalyst preparation or storage of the catalyst composition before its use in the copolymerization process. The tendency to be coated is associated with the noble character of the palladium metal.

It may be desirable to find an alternative to the paiadium-based catalyst. Nickel and cobalt are other group VIII metals, which can be used in the copolymerization of carbon monoxide with olefinically unsaturated compounds. For example, US-A-398438 describes the use of catalysts based on nickel cyanide. These catalysts, however, show a low polymerization activity despite the application of a high polymerization temperature. In addition, copolymers made with these catalysts contain cyanide as permanent catalysts. It could then be that similar compounds containing cyanide, for example hydrogen cyanide, tin being released from the copolymer during its terminal application uses. This is particularly undesirable when the copolymer is used as a packaging material in contact with the food. An improvement in the polymerization rate was made in Patent EP-A-121965 with samples of the use of catalysts containing nickel or cobalt complexes with a bidentate binder which is 1,3-bis (diphenylphosphino) -propane or , 4-bis (diphenylphosphino) utane. However, in the example in which the molecular weight of the copolymer was determined, it was lower than desirable in many applications. In addition, the polymerization ratio obtained still leaves substantially room for improvements. Patent EP-A-470759 describes the use of catalysts based on nickel complexes with a mercaptocarboxylic acid. From the worked examples, in the last application it can be understood that the polymerization rate carried out were again low. This may conclude that here only unsatisfactory results have been obtained with nickel or cobalt-based catalysts. It has been found that improvements in the preparation of nickel-containing catalysts can be carried out using, here, nickel complexes with a modified bidentate binder. The modification involves the presence of chelated atoms. The improvements reside in the polymerization rate, as well as in the feasible molecular weight. The advantages of this encounter are that in a simple and efficient way the copolymers can be prepared using a catalyst containing non-nickel metal, cyanide-free metal. In addition, the prepared reactor powders can have a very low content of permanent catalysts and have a good color realization. The copolymers have a good level of metal stability and are in principle free of cyanide. It also appears that the use of nickel-based catalysts surprisingly leads to a copolymer with a high molecular weight that a similar catalyst, based on palladium, is used in another form under identical conditions. The results with cobalt were unsatisfactory. Accordingly, the invention relates to a catalyst composition which is based on (a) a nickel cation source, and (b) a bidentate binder of the formula (I): R1R2M1-R-M2R3R4 wherein M1 and M2 represent independently phosphorus, nitrogen, arsenic or antimony, RX, R, R3 and R4 independently represent optionally substituted hydrocarbyl groups on the understanding that at least one of RX, R, R3 and R4 represent a substituted aryl group, and R represents a expansive bivalent group in which the bridge consists of more than two expansive atoms. The invention also relates to a process for the preparation of carbon monoxide copolymers and an olefinically unsaturated compound comprising contacting the monomers in the presence of the catalyst composition according to this invention.

Additionally, the invention relates to a linear carbon monoxide copolymer and an olefinically unsaturated compound in which the copolymer comprises in an amount of up to 500 ppm relative to the weight of the copolymer and in which the copolymer is free or substantially free of palladium . As the nickel cation source, a nickel salt, such as a nickel (II) salt, is conveniently used. Suitable salts include salts of mineral acids such as sulfuric acid, nitric acid, phosphoric acid and sulfonic acids, and organic salts such as nickel acetylacetonate. Preferably a nickel salt of a carboxylic acid is used, for example a carboxylic acid with up to 8 carbon atoms such as formic acid, acetic acid, trifluoroacetic acid, trichloroacetic acid, propionic acid and citric acid. Other preferred nickel salts are nickel halides such as nickel (II) bromide and nickel (II) iodide. Nickel (II) acetate represents a particularly preferred source of nickel cations. Another very convenient source of nickel cations is composed of nickel in a zero valent state, for example a nickel (0) complex, an organic binder, such as a diene or phosphine. Examples of such complexes are nickel (0) bis (triphenylphosphino) dicarbonyl nickel (0) and nickel (0) dicyclooctadiene tetracarbonyl, of which the cationic species can be formed by the reaction, for example, with a strong acid such as the acids defined at this point, for example trifluoroacetic acid. In the binders of formula (I) M1 and M2 preferably represent phosphorus atoms. The groups RX, R2, R3 and R4 are independently hydrocarbyl groups which may optionally be polar substituents. R1, R2, R3 and R4 can independently represent optionally polar alkyl, aryl, aralkyl, alkaryl or cycloalkyl substituent groups typically having up to 20 carbon atoms, more typically up to 10 carbon atoms, with the understanding that at least one of R1 , R2, R3 and R4 represent an aryl substituent group such as an aryl group preferably having up to 20 carbon atoms, more preferably up to 10 carbon atoms. Typically at least one of R1, R2 and at least one of R3 and R4 represent an aryl substituent group, more typically each of R ^ R ^ R ^ R represent an aryl substituent group. Suitable substituents present in the aryl substituent group (s) are alkyl groups, such as the methyl, ethyl or t-butyl groups. However, aryl groups are preferred polar substituents. Polar substituents include halogen atoms, such as fluoride and chloro alkoxy groups such as methoxy and ethoxy groups and alkylamino groups such as methyl amino, dimethylamino and diethylamino groups. Alkoxy groups and alkylamino groups containing in particular up to 5 carbon atoms in each of their alkyl groups. Preferred polar substituents are an alkoxy group, especially a methoxy group. It is preferred that substituent aryl groups R ^ R ^ R3, and R4 are phenyl groups having a substituent typically in the ortho position with respect to M1 or M2. Additional substituents are preferably placed in the ortho position as well as in a position para with respect to M1 or M2. The expansive group R of the binders of formula (I) are typically an organic expansive group having up to 10 carbon atoms. The expansive atoms are preferably carbon atoms, but it is also feasible that one or two expansive atoms are heteroatoms, such as oxygen or silicone atoms. Preferably there are two expansive carbon atoms. The expansive group R can be aliphatic, olefinic or aromatic in nature. However, a 1,2-alkylene group, for example a 1,2-propylene group, a 2,3-butylene group or a 1,2-cyclohexene group, is preferable. R more preferably represents an ethylene group (-CH2-CH2-). The preferred bidentate binders are 1, 2-bis [(2-methoxy-phenyl), phenylphosphino] ethane, 1,2-bis [(2,4-di-methoxyphenyl) phosphino-padan, 1,2-bis [bis (2, 4, 6-tri- methoxyphenyl) phosphino] ethane and, more preferably, 1,2-bis [bis (2-methoxyphenyl) phosphino] ethane. The amount of bidentate binders supplied to the catalyst composition may vary, but is conveniently selected in the range of 0.1 to 2 moles of bidentate binder per gram of nickel atom. Preferably, the amount is in the range of 0.5 to 1.5 moles of binder per gram of nickel atom. The nickel-containing catalyst composition can be based on a source of anions as an additional catalyst component. The skilled person will appreciate that suitable anions are those which are non or only unconvincingly coordinating with the nickel under the polymerization conditions. Examples of suitable anions are protic acid anions, which include acids that are obtained by the combination of Lewis acid and a protic acid and acids which are close to boric acid and a 1,2-diol, a catechol or an acid salicylic. Preferred acids are strong acids, for example those having a pKa of less than 6, in particular less than 4, more in particular less than 2m when measured in aqueous solution at 18 ° C. Examples of suitable protic acids are the acids mentioned above, which may also participate in the nickel salts, for example trifluoroacetic acid. Examples of Lewis acids defined and exemplified at this point, in particular are boron tritluoride, boron pentaluoride, tin dichloride, tin difluoride, tin di (methyl sulfonate), aluminum trifluoride and arsenic pentafluoride, triphenylborane, tris (perfluorophenyl) ) -borane and tris [3, 5-bis (trifluoromethyl) phenyljborane. Examples of protic acids which can be combined with a Lewis acid are sulfonic acids and hydrohalogenic acids, in particular hydrogen fluoride. Very convenient combinations of a Lewis acid with a protic acid are tetrafluoroboric acid and hexafluoroboric acid (HBF4 and HBF6): Other suitable anions are anions of which it seems that they are not stable conjugated acids. Such as tetrahydrocarbylborate anions or carborate anions. Borate anions may comprise the same or different hydrocarbyl groups attached to boron, such as alkyl, aryl, aralkyl, and cycloalkyl groups. Preferred tetraaryl borates are, as tetraphenyl borate, tetrakis [3,5-bis (trifluoromethyl) phenyljborate and tetrakis (perfluorophenyl) borate, and carbonate (B 1? CH 2 2). The source of anions can be acids from which the anions are derivatives, or their salts. Other sources of anions are conveniently Lewis acid, such as halides, in particular fluorides, boron, tin, antimony, aluminum or arsenic. Boron trifluoride and boron pentafluoride are very convenient. Other suitable Lewis acids are hydrocarbylorans. The hydrocarbylborans may comprise a hydrocarbyl group or two or three of the same or different hydrocarbyl groups attached to the boron, such as alkyl, aryl, aralkyl, and cycloalkyl groups, preferably aryl groups. They may also comprise hydrocarbyloxy or hydroxy groups or halogen atoms attached to boron. Examples of suitable hydrocarbylborans are triphenylborane, tris (perfluorophenyl) borane and tris [3,5-bis (trifluoromethylphenyl) bromine, etc. Again other convenient compounds in which to function as a source of anions are aluminoxanes, in particular methyl aluminoxanes and aluminoxanes t- Butyl The quantity of the anion source which is preferably selected to which is provided in the range of 0.5 to 50 equivalents of anions per gram of nickel atom, in particular in the range of 0.1 to 25 equivalents of anions per gram of nickel atom However, aluminoxanes can be used as such an amount that the molar ratio of aluminum to nickel is in the range of 4000: 1 to 10: 1, preferably from 2000: 1 to 100: 1, more preferably from 500: 1 to 200: 1. The activity of the catalyst composition is such that quantities in the range of 10"7 to 10" 2 per gram of nickel atom per mole of olefinically unsaturated compound to be copolymerized are suitable. Preferably, the amount would be 10"6 to 10" 3, on the same basis. The olefinically unsaturated compounds which can be used as monomers in the copolymerization process of the invention include compounds consisting exclusively of carbon and hydrogen and compounds which in addition comprise heteroatoms such as unsaturated esters. Unsaturated hydrocarbons are preferred. Examples of suitable monomers are lower? -fins, co-or ethane, propan? and butane-1, cyclic olefins such as cyclopentane, aromatic compounds, such as styrene and alpha-methylstyrene and vinyl esters such as vinyl acetate and vinyl propionate. Preference is given to ethane and mixtures of ethane with another α-olefin such as propane or butane-1. Generally, the molar ratio of one form of carbon monoxide to another form of the olefinically unsaturated compound (s) can be selected within a wide range, for example in the range of 1:50 to 20: 1. However, it is preferred to use a molar ratio in the range of 1:20 to 2: 1. The process of the invention is conveniently carried out in the presence of a diluent. Preferably a diluent is used in which the polymers are insoluble or virtually insoluble so that they form a suspension until their formation. Recommended diluents are polar organic liquids such as ketones, ethers, esters or amides. Preferably, protic liquids are used, such as monohydric and dihydric alcohols, in particular lower alcohols having more than 4 carbon atoms per molecule, such as methanol and ethanol. The process of this invention can be carried out as a gas phase process in the case where the typically used catalyst is deposited in a particular material solid or chemically bonded thereto. When a diluent is used, in which the copolymer forms a suspension it is preferred to have a particular solid material suspended in the diluent before the monomers are connected to the catalyst composition. Particular suitable solid materials are silica, polyethylene and carbon monoxide copolymers and an olefinically unsaturated compound, preferably a copolymer on which it is based on the same monomers as the prepared copolymer. The amount of the particular solid material is preferable in the range of 0.1 to 20 g, particularly 0.5 to 10 g per 100 g of diluent. The conditions under which the process of the invention is carried out, include the use of elevated temperatures and pressures, such as between 20 and 200 ° C, in particular between 30 and 130 ° C, and between 1 and 200 bar, in particular between 5 and 500 bar. The carbon monoxide pressure is typically at least 1 bar.

The copolymers can be coated with the polymerization mixture using conventional techniques. When a diluent is used, the co-polymers can be coated by filtration or by evaporation of the diluent. The copolymer can be purified by some prolonged washes. The copolymers are conveniently prepared in units of origin from carbon monoxide or otherwise and units originating from olefinically unsaturated compound (s) or otherwise may be provided in an alternative or substantially alternative device. The term "substantially alternative" will generally be understood by the skilled person as a means in which the molar ratio of the units originating from the carbon monoxide to the units originating from the olefinically unsaturated compound (s) is about 35:65, in particular about 40:60. When the polymers are alternative, this ratio equals 50:50. A high Limiting Viscosity Number (LVN) or intrinsic viscosity of the LVN copolymers is dictated by a high molecular weight. The LVN is calculated from the determined viscosity values, measured by different concentrations of m-cresol copolymers at 60 ° C. It is preferred to prepare copolymers having LVN in the range from 0.2 to 10 dl / g, in particular from 0.4 to 8 dl / g, more in particular from 0.6 to 6 di. It is also preferred to prepare copolymers which have a melting point above 150 ° C, as determined by Scanning Differential Calorimetry (DSC). For example, linear copolymers of carbon monoxide and ethane and linear copolymers of carbon monoxide, ethane and other α-olefin which are alternative or become substantially alternative in this category. It is particularly preferred to prepare alternating linear copolymers of carbon monoxide and ethane or linear alternating copolymers of carbon monoxide, ethane and other α-olefin in which the molar ratio of the other α-olefin to ethane is typically about 1: 100, preferably in the range of 1: 100 to 1: 3, more preferably in the range of 1:50 to 1: 5. In addition, for practical reasons the nickel content of the copolymers will typically be about 0.01 ppm, relative to the copolymer prisoner. It is preferred to prepare copolymers which have a nickel content in the range of 0.05 to 300 ppm, in particular 0.1 to 200 ppm, relative to the weight of the copolymer. The copolymers are substantially free, preferably of palladium. "Substantially free of palladium" indicates to the skilled person that the palladium content is lower than the value normally carried when a palladium-based catalyst is employed in the copolymerization, for example less than 1 ppm, in particular, less than 0.1 ppm, relative to the weight of the copolymer. Alternatively, it is preferred that, if the palladium is present, the weight ratio of palladium to nickel is less than 1:50, in particular, less than 1: 100 or more particularly even less than 1: 200. Preferably, the copolymers are free tin or substantially free of organic cyanides. Substantially free of organic cyanides can be considered copolymers of which the content of organic cyanide, measured as the weight of CN, is less than 10 ppm, in particular less than 1 ppm, more in particular less than 0.1 ppm, relative to the weight of the copolymer. The content of cyanide copolymers can be determined by the expansiveness of the cyanide within an aqueous solution, for example by dissolving the copolymer in a convenient polar solvent, such as exafluoroisopropanol, and adding water, after which the cyanide content of the aqueous solution can be determined using standard methods.

The invention will be illustrated by the following examples of the preparation of linear alternative carbon monoxide / olefin copolymers.

Example 1 A carbon monoxide / ethane copolymer was prepared as follows. A stirred 200 ml autoclave, was charged with a catalyst solution consisting of 100 ml of methanol, 0.25 mmol of nickel (III) acetate, 1 mmol of trifluoroacetic acid, and 0.3 mmol of 1,2-bis [bis (2-methoxy-phenyl) phosphino Ethane The air in the autoclave was eliminated by evacuation. The autoclave was pressurized with ethane at 20 bar and additionally with 30 bar of carbon monoxide, that is to say a total of ethane and carbon monoxide of 50 bar. Subsequently the autoclave was heated to 90 ° C. After 5 hours the polymerization was terminated by cooling to room temperature and subsequently the pressure was released. The powder of the copolymer reactor was coated by filtration, washed with methanol and dried at 60 ° C under nitrogen at a reduced pressure.

There was obtained 13.5 g of a white water copolymer having an LVN of 1.67 dl / g, which corresponds to an average number of molecular weight of about 25000.

Example 2 (by comparison) A carbon monoxide / ethane copolymer was prepared as described in Example 1, but with the difference that 0.3 mmol of 1, 3-bis [bis (2-methoxyphenylphosphinoj-propane was used instead of 1,2-bis [(2-methoxy-phenyl) phosphino-padan and the polymerization time was 10 hours instead of 5 hours.) 0.7 g of a yellowish white copolymer was obtained.

Example 3 (by comparison) A carbon monoxide / ethane copolymer was prepared as described in Example 1, but with the difference that 0.3 mol of 1,2-bis (diphenylphosphino) ethane were used instead of l, 2- bis [bis (2-methoxyphenyl) phosphinojetane and the polymerization time was 10 hours instead of 5 hours. 0.6 g of a yellowish white copolymer was obtained.

Example 4 (by comparison) A carbon monoxide / ethane copolymer was prepared as described in Example 1, but with the difference that 0.3 mmol of 1,3-bis (diphenylphosphinopropane were used instead of 1,2-bis [ bis (2-methoxyphenyl) phosphinojetane and the polymerization time was 3 hours instead of 5 hours 0.1 g of a yellowish white copolymer was obtained.

Example 5 A carbon monoxide / ethane copolymer was prepared as described in Example 1, but with the difference that (1) the catalyst solution consisted of 100 ml of methanol, 0.1 mmol of nickel (II) acetate, 0.2 mmol of tetrafluoroboric acid, and 0.12 mmol of l, 2-bis [bis (2-methoxyphenyl) phosphinopathene, (2) the temperature was 100 ° C instead of 90 ° C, and (3) the polymerization time was 3 hours instead of 5 hours. He obtained 8 g of white water copolymer that has an LVN of 1.64 dl / g.

Example 6 A copol er? of carbon monoxide / ethane was prepared as described in Example 1, but with the difference that (1) the catalyst solution consisted of 100 ml of methanol, 0.1 mmoi of nickel acetate (II), 0.2 mmol of trifluoroacetic acid, and 0.12 mmol of l, 2-bis [bis (2-methoxyphenyl) phosphinojetane, (2) the temperature was 100 ° C instead of 90 ° C, (3) ethane and carbon monoxide they were fed at 30 bar and 20 bar pressure instead of 20 bar and 30 bar, respectively, and (4) the polymerization time was 1 hour instead of 5 hours. 4.5 g of a white water copolymer having an LV of 2.10 dl / g was obtained.

Example 7 (by comparison) A carbon monoxide / ethane copolymer was prepared as described in Example 6, but with the difference that the catalyst solution contained 0.1 mmol of cobalt (III) acetate instead of nickel acetate (II). ) and that the polymerization time was 3 hours instead of 1 hour. 0.3 g of a yellowish white copolymer was obtained.

Example 8 A carbon monoxide / ethane copolymer was prepared as described in Example 1, but with the difference that (1) the catalyst solution consisted of 100 ml of methanol, 0.02 mmol of nickel (II) acetate, 0.04 mmol of trifluoroacetic acid, and 0.24 mmol. of l, 2-bis [bis (2-methoxyphenyl) -phosphinojetane, (2) the temperature was 100 ° C instead of 90 ° C, (4) the ethane and the carbon monoxide were fed at 40 bar and 20 bar. pressure bar instead of 20 bar and 30 bar, respectively, and (4) the polymerization time was 1.5 hours instead of 5 hours. 6.0 g of a white water copolymer having an LVN of 2.35 dl / g was obtained.

Example 9 A carbon monoxide / ethane copolymer was prepared as described in Example 1, but with the difference that (1) the catalyst solution consisted of 100 ml of methanol, 0.02 nickel acetate (II) nickel, 0.04 mmol of trifluoroacetic acid, and 0.024 mmol of l, 2-bis [bis (2-methoxyphenyl) -phosphinojetane, (2) the temperature was 100 ° C instead of 90 ° C, (4) ethane and carbon monoxide they were fed at 30 bar and 10 bar pressure instead of 20 bar and 30 bar, respectively, and (4) the polymerization time was 0.12 hours instead of 5 hours. 3.5 g of a white water copolymer having an LVN of 5.95 dl / g was obtained.

Example 10 A carbon monoxide / ethane copolymer was prepared as described in Example 1, but with the difference that (1) the catalyst solution consisted of 100 ml of methanol, 0.1 mmol of nickel (II) acetate, 0.12 mmol of 1, 2-bis [bis (2-methoxyphenyl) -phosphinojetane, (2) ethane and carbon monoxide were fed at 40 bar and 10 bar pressure instead of 20 bar and 30 bar, respectively, (3) additionally carbon monoxide was fed at a pressure of 10 bar at three points at a time, viz. at 0.5, 1.0 and 1.5 hours after the starting point of the copolymerization, and (4) the polymerization time was 2.5 hours instead of 5 hours. 11 g of a white water copolymer having an LVN of 4.1 dl / g was obtained.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the manufacture of the objects to which it refers. Having described the invention as above, the content of the following is claimed as property.

Claims (14)

1. A catalyst composition characterized in that it is based on (a) a nickel cation source, and (b) a bidentate binder of the general formula (I): R1R2M1-R-M2R3R4 wherein M1 and M2 independently represent phosphorus, nitrogen, arsenic or antimony, RX, R2, R3 and R4 independently represent optionally substituted hydrocarbyl groups on the understanding that at least one of R1, R2, R3 and R4 represent a substituted aryl group, and R represents a bivalent expansive group in which the Bridge consists of 'more than two expansive atoms.

2. A catalyst composition according to claim 1, characterized in that the nickel cation source comprises a nickel salt or a nickel (0) complex compound with an organic binder.

3. A catalyst composition according to claim 1 or 2, characterized in that M1 and M2 represent phosphorus atoms and at least one of R1 and R2 and at least one of R3 and R4 of the bidentate binder of the general formula (I), typically each of R1, R2, R3 and R4, represent a polar substituent aryl group.

4. A catalyst composition according to claim 3, characterized in that the polar substituent aryl group is a substituent phenyl group in an ortho position with respect to M1 or M2 with an alkoxy group, especially a methoxy group.

5. A catalyst composition according to any of claims 1-4 characterized in that the bivalent expansive group R is a 1,2-alkylene group, preferably an ethylene group (-CH 2 -CH 2 -).

6. A catalyst composition according to any of claims 1-5 characterized in that the amount of the bidentate binder of the general formula (I) is selected from the range of 0.5 to 1.5 moles per gram of the nickel atom.

7. A process according to any of claims 1-6, characterized in that the catalyst composition is based as an additional component, in a source of anions selected from sources of protic acid anions, tetrahydrocarbylborate anions. and carborate anions, or selected from Lewis acids and aluminoxanes, with anions are preferably applied in amounts of 1 to 25 equivalents per gram of the nickel atom, on the understanding that the aluminoxanes are preferably applied in such amount that the molar ratio of aluminum to Nickel is in the range of 2000: 1 to 100: 1, in particular 500: 1 to 200: 1.

8. A process for the preparation of carbon monoxide copolymers and an olefinically unsaturated compound comprises contacting the monomers in the presence of a catalyst composition as claimed in any of claims 1-7.

9. A process according to claim 8, characterized in that the olefinically unsaturated compound is an unsaturated hydrocarbon, such as ethane or a mixture of ethane with another α-olefin.

10. A process according to claim 8 or 9, characterized in that the contacting is carried out in a diluent in which the copolymers are insoluble or virtually insoluble, such as methanol or ethanol, so as to form a suspension of their formulation, using such amount of the catalyst composition that the amount of the nickel present is in the range of 10"7 to 10" 2 per gram of atom, preferably 10"to 10 ~ 3 per gram of atom per mole of the olefinically unsaturated compound for copolymerizing, and applying a molar ratio of carbon monoxide to the olefinically unsaturated compound (s) in the range of 1:50 to 20: 1, preferably from 1:20 to 2: 1, a temperature between 20 and 200 ° C, in particular between 30 and 130 ° C, and a pressure between 1 and 200 bar in particular between 5 and 500 bar.

11. A liner copolymer of carbon monoxide and an olefinically unsaturated compound in which the copolymer comprises nickel in an amount of up to 500 ppm relative to the weight of the copolymer and in which the copolymer is free or substantially free of palladium.

12. A copolymer according to claim 11, characterized in that the copolymer has a nickel content in the range of 0.5 to 300 ppm, in particular 0.1 to 200 ppm, relative to the weight of the copolymer.

13. A copolymer according to claim 11 or 12, characterized in that if the palladium and / or organic cyanide are present, the content of palladium is less than 1 ppm and the content of the organic cyanide is less than 10 ppm, calculated as the weight of CN, both contents are relative to the weight of the polymer.

14. A copolymer according to any of claims 11-13, characterized in that the copolymer is a linear alternative copolymer of carbon monoxide and ethane or a linear alternative copolymer of carbon monoxide, ethane and other α-olefin.