WO1999061508A1

WO1999061508A1 - Process for the copolymerization of carbon monoxide with an olefinically unsaturated compound

Info

Publication number: WO1999061508A1
Application number: PCT/EP1999/003585
Authority: WO
Inventors: Jacobus Adrianus Bakkum; Sami Karaborni; Martien Krijger; Guy Lode Magda Maria Verbist; Rudolf Jacobus Wijngaarden; Nico Maria VAN OS
Original assignee: Schrier Johanna Maria Hendrika; Shell Internationale Research Maatschappij BV
Current assignee: Schrier Johanna Maria Hendrika; Shell Internationale Research Maatschappij BV
Priority date: 1998-05-26
Filing date: 1999-05-21
Publication date: 1999-12-02
Anticipated expiration: 2000-11-26
Also published as: AU4367399A

Abstract

A process for copolymerization of carbon monoxide with an olefin comprises contacting the monomers in the presence of a Group VIII metal catalyst, in a two phase reaction mixture comprising a polar phase, for example methanol/water, suspended in a continuous apolar phase, for example dodecane. The polar phase contains the catalyst, and the resultant polymer. The continuous apolar phase retains low viscosity throughout the process and aids good mixing throughout the process.

Description

PROCESS FOR THE COPOLYMERIZATION OF CARBON MONOXIDE WITH AN OLEFINICALLY UNSATURATED COMPOUND

The invention relates to a process for the preparation of copolymers comprising copolymerizing carbon monoxide with an olefinically unsaturated compound, or compounds, in the presence of a Group VIII metal containing catalyst composition.

Processes of this kind are well known in the art, for example from EP-A-213671 and EP-A-619335. The copolymers prepared are linear copolymers wherein the monomer units originating from carbon monoxide and the monomer units originating from the olefinically unsaturated compound, or compounds, occur in alternating or substantially alternating order.

In EP-A-213671 it is mentioned that such a copolymerization is carried out in a liquid diluting agent, and that lower alcohols such as methanol and ethanol are very suitable as liquid diluting agents . In the examples methanol is the diluting agent. The copolymer is not soluble in methanol, or other lower alcohols, and at the end of the process the precipitated copolymer is filtered off. Such processes are called suspension or slurry copolymerization processes.

In EP-A-619335 it is mentioned that the catalyst compositions for copolymerization of carbon monoxide and an olefinically unsaturated compound can be used in either the gas-phase or the liquid-phase, the term liquid-phase also including suspension polymerization processes, which are also called slurry processes . Suitable solvents are said to be ketones (e.g. acetone), ethers, glycol ethers, chlorinated solvents (e.g. chloroform, dichloromethane) , hydrocarbon solvents (e.g. cyclohexane, toluene), methanol and ethanol . The processes described in EP-A-213671 and EP-A-619335 are typical of processes described in many patent publications relating to such copolymers. These reflect the fact that in real-life practice polyketone copolymers are made by slurry copolymerization. This is despite the fact that the copolymer produced tends to be a rather fluffy solid. This causes the viscosity of the slurry to increase dramatically already at a low concentration of the copolymer, and therefore to give rise to problems in keeping the reactor contents well mixed as the copolymerization proceeds.

We have now determined that this morphology problem can be avoided by carrying out the polymerization in a two liquid phase reaction mixture. Namely, it has been found that in such reaction mixtures the morphology problem arising from the fluffy polymer is avoided: the continuous phase still has a low viscosity, even if the polar phase is rigid with fluffy polymer.

In accordance with a first aspect of the present invention there is provided a process for the preparation of a linear alternating polyketone copolymer, from carbon monoxide and an olefinically unsaturated compound, comprising copolymeπzing the monomers in the presence of a suitable catalyst composition, characterized in that the process is carried out in a reaction mixture which comprises a polar phase and an apolar phase, said apolar phase being a continuous phase, and the catalyst composition and the copolymer formed being retained in said polar phase. The polar phase and the apolar phase may be bicontmuous phases. Bicontinuous phases are generally characterized by intertwined, sample spanning pathways of both phases separated by surfactant sheets. Preferably, however, the apolar phase is a continuous phase within which the polar phase is a dispersed discontinuous phase. Preferably, the polar phase is dispersed within the apolar phase as droplets. Typically the droplets may be of average diameter in the range from 5 nm to 500 μm. The reaction mixture may be tailored by means of selection of the respective compounds of the polar and apolar phases, of their proportions, and of the amount and type of a stabilising surfactant, or surfactants, when employed. It will be appreciated by the person skilled in the art that the process of the invention is one which would often be called an emulsion polymerization reaction, but that term is not used in the definitions herein because of lack of consensus as to the boundaries of the term "emulsion".

When the average diameter of the droplets of the polar phase is of the order of microns, for example in the range of 500 nm to 50 μm, the reaction mixture may tend to be called an emulsion, or ordinary emulsion, by many persons skilled in the art. A surfactant or surfactants will generally be used, in an amount typically 0.1-2% by total weight of the emulsion.

In the context of this patent document, by "average diameter of the droplets" is meant the Sauter mean value of the diameter.

When the average diameter of droplets of the polar phase is in the range up to 500 nm the reaction mixture may tend to be called a microemulsion or miniemulsion, by many persons skilled in the art. It will frequently involve the presence of an appreciable amount of a suitable surfactant or surfactants, typically 5-15 wt% by total weight of the microemulsion or miniemulsion.

When the average diameter of the droplets of the polar phase is above 50 μm, it may tend to be called a two-phase suspension, by many persons skilled in the art. A surfactant will generally not be used.

Whilst said ordinary emulsions are preferred reaction mixtures in the present invention there is no reason why the invention cannot be applied using microemulsions or min emulsions, or two-phase suspensions, as described above, and such are within the ambit of the present invention.

In the practice of the present invention the proportion by volume of the polar phase to the apolar phase is a matter of choice. In preferred embodiments in which a polar phase is dispersed as droplets in a continuous apolar phase, it is generally desirable to select the proportion of the continuous apolar phase such that it is at or slightly above the minimum amount required to permit adequate stirring of the reaction mixture throughout the process. Consequently the amount of the discontinuous polar phase retaining the copolymer which forms is at or slightly below a maximal amount. The proportion by volume of the apolar phase to the polar phase may typically be 30-70 : 70-30, preferably 40-60 : 60-40.

As mentioned above the nature of the reaction mixture may be tailored, and there will be a wide variety of polar compounds, apolar compounds and surfactants which can in different combinations form two-phase reaction mixtures suitable for use in the present invention, such that the catalyst and forming polymer are present in the polar phase. All-embracing definitions or lists cannot be given and the devising of suitable reaction mixtures which are in accordance with the present invention represents work within the scope of the person skilled in the art, using his ordinary skill and knowledge and/or undertaking work by the ordinary process of trial and error. However, by way of guidance we can state the following, based on work carried out to date.

The polar phase may suitably comprise, for example, a monohydπc or polyhydric alcohol, a ketone or a halogenated hydrocarbon. A suitable monohydric alcohol is a compound of formula R^-OH, wherein Rl is a C^**__6 alkyl group, preferably a C]__4 alkyl group. Ethanol or, especially, methanol are of particular interest. A suitable polyhydric alcohol is a C2-4 alkane substituted by 2 or 3 hydroxy groups. Examples are ethylene glycol, propylene glycol and glycerol . A suitable ketone is a di (C]__4alkyl) ketone . An example is acetone. A suitable halogenated hydrocarbon is a halogenated benzene or a halogenated C__ alkane. Preferred halogen substituents are fluorine and chlorine. Examples of such solvents are chlorobenzene and dichloromethane .

The polar phase may suitably comprise water. The polar phase may suitably comprise a first polar compound and a second polar compound, being liquids miscible with each other. Their relative proportions by volume may suitably be 5-95 : 95-5, preferably 30-70 :

70-30, most preferably 40-60 : 60-40. By having two (or more) such polar compounds the characteristics of the polar phase may easily be tailored. Said first polar compound may suitably be water. Said second polar compound may suitably be one of the organic compounds mentioned above but is preferably a polyhydric or, especially, a monohydπc alcohol, as defined above. Methanol/water blends are especially preferred.

Alternatively or additionally, the characteristics of the polar phase may be altered by the addition of compounds which dissolve therein to form ions.

The apolar phase may suitably comprise a Cg-20 alkane, preferably a C_n-14 alkane.

The apolar phase may comprise a first apolar compound and a second apolar compound, miscible with each other. The relative proportion by volume may suitably be 5-95 : 95-5, preferably 30-70 : 70-30. By having two (or more) apolar compounds miscible with each other the characteristics of the apolar phase may easily be tailored. However a one-component apolar phase will generally be preferred as there are fewer requirements of the compound (s) of the apolar phase than of the polar phase. To a person skilled in the art it will be clear that the compound (s) thereof have low solubility in the polar phase and that the compound (s) of the polar phase, and the catalyst and the copolymer, have low solubility in it.

A blend comprising a large number of components may be used. For example if an alkane fraction from a refinery is used, this fraction is frequently a blend of close homologues .

The apolar phase may be a liquid olefinically unsaturated compound, being a reactant of the copolymerization. This is distinct from a situation where the apolar phase is not itself a reactant, but an agent for the delivery of the reactants from the gas phase in the reactor, to the polar phase where the reaction takes place. Where the apolar phase comprises a liquid olefinically unsaturated compound it may be the sole constituent of the apolar phase or may be in admixture with one or more other constituents, but itself a substantial constituent, for example constituting at least 20% by weight of the apolar phase, preferably at least 50%. One olefinically unsaturated compound which may be particularly suitable in this respect is propene .

As mentioned above a surfactant may desirably be present in order to stabilise the reaction mixture. Many surfactants will be suitable. Examples are alkoxylates, for example alkylphenol alkoxylates, alcohol alkoxylates, polyol alkoxylates, amine alkoxylates, ester alkoxylates, acid alkoxylates; sulphonates, for example alkylaryl sulphonates, alkane sulphonates; alkane sulphates, for example sodium lauryl sulphates; ether sulphates, for example sodium lauryl ether sulphates; alkane phosphates; esters of alkylene oxide polymers; and saponified carboxylic acids, for example derivatives of fatty acids, rosin acid and tall oil acids. Thought to be especially suitable are alcohol alkoxylates of the general formula R2-E-OH where R² represents a Cg-24 preferably Cι_2-18' alkyl group, and E represents a polyalkylene oxide chain, preferably having an average 3 to 20, especially 5-10, alkylene oxide units, those alkylene oxide units preferably being ethylene oxide units, or ethylene oxide and propylene oxide units together.

However, the surfactant of choice for the particular reaction will depend on the choice of chemicals for the polar phase and the apolar phase and is a matter for the ordinary exercise of the expertise of the person skilled in the art.

Further, the person skilled in the art can gauge the desired amount of surfactant, when present, once other choices have been made, and can optimise the amount by means of trial and error work, if required. However, typically, a surfactant may suitably be present in amount in the range 0.1-15% by weight of the liquid phases, preferably 0.1-2%, especially 0.5-1.5%, for an ordinary emulsion, as is preferred, and 2-10% for a microemulsion or miniemulsion. A two-phase suspension is likely to have no surfactant.

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 hetero atoms, such as unsaturated esters, ethers and amides. Unsaturated hydrocarbons are preferred. Examples of suitable olefinic monomers are lower olefins, such as ethene, propene and butene-1, cyclic olefins such as cyclopentene, aromatic compounds, such as styrene and α-methylstyrene and vinyl esters, such as vinyl acetate and vinyl propionate. Most preference is given to ethene and mixtures of ethene with another olefinically unsaturated compound, in particular an α-olefin, such as ■propene or butene-1. The term "lower" used in this document to specify an organic compound has the meaning that the organic compound contains up to 6 carbon atoms. Generally, the molar ratio of on the one hand carbon monoxide and on the other hand the olefinically unsaturated compound (s) used as monomer is selected in the range of 1:5 to 5:1. Preferably the molar ration is in the range of 1:2 to 2:1, substantially equimolar rations being preferred most.

Examples of suitable Group VIII metals for use in the catalyst composition are nickel and cobalt. However, the Group VIII metal is preferably a noble Group VIII metal, of which palladium is most preferred. The Group VIII metal is typically employed as a cationic species. As the source of Group VIII metal cations conveniently a Group VIII metal salt is used. Suitable salts include salts of mineral acids, such as sulphuric acid, nitric acid, phosphoric acid, perchloric acid and sulphonic acids, and organic salts, such as acetylacetonates . Preferably, a salt of a carboxylic acid is used, for example a carboxylic acid with up to 8 carbon items, such as acetic acid, trifluoroacetic acid, trichloroacetic acid, propionic acid and citric acid. Palladium (II) acetate and palladium (II) trifluoroacetate represent particularly preferred sources of palladium cations. Another suitable source of Group VIII metal cations is a compound of the Group VIII metal in its zero- valent state. The catalyst composition of the invented process is preferably based, as an additional component, on a ligand which forms a complex with the Group VIII metal. It would appear that the presence of two complexing sites in one ligand molecule significantly contributes to the activity of the catalysts. It is thus preferred to use a ligand containing at least two dentate groups which can complex with the Group VIII metal. Although less preferred, it is also possible to employ a monodentate ligand, i.e. a compound which contains a single dentate group which can complex with the Group VIII metal, in particular a dentate group of phosphorous. Suitably a bidentate ligand is used which contains two phosphorus-, nitrogen- or sulphur- containing dentate groups. It is also possible to use a mixed bidentate ligand such as 1-dιphenylphosphmo- 3-ethylthιopropane . A preferred group of bidentate ligands can be indicated by the general formula _R3_R4_M1__R-_M2R5_R6 _(j)

In this formula M^*-- and M² independently represent a phosphorus, nitrogen, arsenic or antimony atom, R3, R4 , X³ and R^ independently represent a non-substituted or polar substituted hydrocarbyl group, in particular of up to 10 carbon atoms, and R represents a bivalent organic bridging group containing at least 1 atom in the bridge, for example a carbon atom or a nitrogen atom. In the ligands of formula (I) M-¹- and M² preferably represent phosphorus atoms. R3, R4 , R^ _and R^ may independently represent optionally polar substituted alkyl, aryl, alkaryl, aralkyl or cycloalkyl groups.

Preferably at least one of R3 , R4 , R5 and R^ represents an aromatic group, in particular an aromatic group which is polar substituted.

Suitable polar groups include halogen atoms, such as fluorine and chlorine, alkoxy groups such as methoxy and ethoxy groups and alkylammo groups such as methylamino, dimethylammo and diethylammo groups. Alkoxy groups and alkylammo groups contain m particular up to 5 carbon atoms in each of their alkyl groups.

It is preferred that one or more of R3 , R4 , R5 _ancj 6 represents an aryl group, preferably a phenyl group, substituted at an ortho position with respect to M¹ or M² with an alkoxy group, especially a methoxy group.

In the ligands of formula (I), R preferably represents a bivalent organic bridging group containing from 2 to 4 bridging atoms, at least two of which may be carbon atoms. Examples of such groups R are -CH2-CH2-,

-CH₂-CH₂-CH₂, -CH₂-C(CH₃)2-CH2-, -CH₂-Si (CH3 ) ₂-CH₂-, and

-CH2-CH2-CH2-CH2- . Preferably R is a trimethylene group.

Preferred ligands are 1 , 3-bis [bis (2 , 4-dimethoxyphenyl ) - phosphino] propane, 1, 3-bis [bis (2, 4 , 6-trimethoxyphenyl) - phosphino] propane and, more preferred, 1, 3-bis [bis (2- ethoxyphenyl ) phosphino] propane .

Other suitable bidentate ligands are nitrogen containing compounds of the general formula

Xl X²

/ \ / \ N = C - C = N wherein X^*-- and X² independently represent organic bridging groups each containing 3 or 4 atoms in the bridge at least 2 of which are carbon atoms. There may be an additional bridging group connecting the bridging groups

X-*- and X². Examples of such compounds are 2, 2 ' -bipyridine, 4 , 4 ' -dimethyl-2, 2 ' -bipyridine,

4,4' -dimethoxy-2, 2 ' -bipyridine, 1, 10-phenanthroline, 4 , 7-diphenyl-l, 10-phenanthroline and 4 , 7-dimethyl- 1, 10-phenanthroline . Preferred compounds are 2 , 2 ' -bipyridine and 1, 10-phenanthroline . Again other suitable bidentate ligands are sulphur containing compounds of the general formula

R⁷S-Q-SR⁸ wherein X and R° independently represent a non- substituted or polar substituted hydrocarbyl group and Q represents a bivalent bridging group containing 2 to

4 carbon atoms in the bridge . The groups R⁷ and R^**-¹ are preferably alkyl groups, each having in particular up to 10 carbon atoms. Very suitable bis thio compounds are 1, 2-bιs (ethylthio) ethane and 1, 2-bιs (propylthio) ethene . The amount of bidentate ligand supplied may vary considerably, but is usually dependent on the amount of Group VIII metal present in the catalyst composition. Preferred amounts of bidentate ligands are m the range of from 0.5 to 8, more preferably in the range of from 0.5 to 2 moles per gram atom of Group VIII metal, unless the bidentate ligand is a nitrogen bidentate ligand, m which case the bidentate ligand is preferably present in an amount of from 0.5 to 200 and in particular 1 to 50 moles per gram atom of Group VIII metal. The monodentate ligands are preferably present in an amount of from 0.5 to 50 and in particular 1 to 25 moles per gram atom of Group VIII metal.

The Group VIII metal containing catalyst compositions may be based on another additional component which functions during the copolymerization as a source of anions which are non- or only weakly co-ordinating with the Group VIII metal under the conditions of the copolymerization. It will be appreciated that the weakness of the co-ordination of the anions to the Group VIII metal is critically dependent upon the polarity of the polar phase and determination of suitable reaction mixtures which permit the weaknesses of co-ordination within the polar phase for good polymerization may be needed, but will be straightforward for a skilled person in the art to determine. For example, if trial and error work shows a particular copolymerization to be unsuccessful a prime cause is likely to be that the polar phase is insufficiently polar to allow the anions to the Group VIII metal to leave. The solution may be to use an additional component which supplies particularly weakly co-ordinating anions, and/or to use a polar phase of higher polarity. Thus, whilst certain combinations (e.g. of too strongly co-ordinating anions and too weakly polar phases) may not be suitable, it is believed that any of the additional components customarily used may be used in the processes of the invention. Such typical additional components are, for example, protic acids, salts of protic acids, Lewis acids, acids obtainable by combining a Lewis acid and a protic acid, and salts derivable from such combinations. Suitable are strong protic acids and their salts, which strong protic acids have in particular a pKa of less than 6, more in particular less than 4, preferably less than 2, when measured in aqueous solution at 18 °C . Examples of suitable protic acids are the above mentioned acids which may also participate m the Group VIII salts, e.g. perchloric acid and trifluoroacetic acid. Suitable salts of protic acids are, for example, cobalt and nickel salts. Other suitable protic acids are adducts of boric acid and 1,2-dιols, catechols or salicylic acids. Salts of these adducts may be used as well. Suitable Lewis acids are, for example, BF3, AIF3, SF5 and Sn(CF3Sθ3)2_' and also hydrocarbylboranes . Protic acids with which Lewis acids may be combined are for example sulphonic acids and hydrohalogenic acids, in particular HF. A very suitable combination of a Lewis acid with a protic acid is tetrafluoroboπc acid (HBF4). Other compounds which function during the copolymerization as a source of anions which are non- or weakly co-ordinating with the Group VIII metal are salts which contain one or more hydrocarbyl- borate anions or carborate anions, such as sodium tetrakis [bιs-3, 5- (trifluoromethyl ) phenyl] borate, lithium tetrakis (perfluorophenyl) borate and cobalt carborate (Co (Bι_^*]_CH^*]_2 ) 2 ) • Again other compounds which may be mentioned in this context are aluminoxanes, in particular methyl aluminoxanes and t-butyl aluminoxanes. Of the said additional components mentioned above hydrocarbylborane compounds appear to be especially suitable. Preferred are compounds of formula BXYZ where at least one of the groups X, Y and Z represents an optionally substituted phenyl group. Any group X, Y and Z which is not an optionally substituted phenyl group may suitably be a Cι__g alkyl group (especially C-_j__4 alkyl) or a C]__5 haloalkyl group (especially C-_]__ fluoroalkyl) .

Preferably at least two, and most preferably all three, of the groups X, Y and Z independently represent an optionally substituted phenyl group.

Preferably groups X, Y and Z are identical. An optionally substituted phenyl group X, Y and Z is suitably a phenyl group optionally substituted by 1-5 halogen atoms or by 1-3 haloalkyl groups. Preferred halogen substituents are 1-5 fluorine atoms or 1 bromine atom (preferably para-located) or 1 chlorine atom (preferably para-located) . Preferred haloalkyl substituents are C_-4 fluoroalkyl groups, especially trifluoromethyl . Examples of preferred groups X, Y and Z are phenyl, pentafluorophenyl, p-chlorophenyl, p-bromophenyl and 3, 5-bιs (trifluoromethyl) phenyl.

Particular preferred hydrocarbylborane compounds are tπphenylborane and tris [bιs-3 , 5- (trifluoromethyl) phenyl] borane, and, especially tris (pentafluorophenyl) borane .

The amount of the additional component which functions during the copolymerization as a source of anions which are non- or only weakly co-ordinating with the Group VIII metal is preferably selected in the range of 0.1 to 50 equivalents per gram atom of Group VIII metal, in particular in the range of from 0.5 to 25 equivalents per gram atom of Group VIII metal. However, the aluminoxanes may be used m such quantity that the molar ratio of aluminium to the Group VIII metal is in the range of from 4000:1 to 10:1, preferably from 2000:1 to 100:1. The amount of catalyst composition used in the process of the invention may vary between wide limits. Recommended quantities of catalyst composition are in the range of 10^~8 to 10^~2, calculated as gram atoms of Group VIII metal per mole of olefinically unsaturated compound to be copolymerized with carbon monoxide. Preferred quantities are in the range of 10^~7 to 10^~3 on the same basis.

The performance of Group VIII metal catalyst compositions in the copolymerization process may be improved by introducing an organic oxidant, such as a quinone or an aromatic nitro compound. Preferred oxidants are qumones selected from the group consisting of benzoqumone, napththoquinone and anthraqumone . The quantity of oxidant is advantageously in the range of from 1 to 50, preferably in the range of from 1 to 20 mole per gram atom of metal of Group VIII.

The copolymerization process is usually carried out at a temperature between 20 and 200 °C, preferably at a temperature in the range of from 30 to 150 °C, and usually applying a pressure between 0.2 and 20 MPa, pressures in the range of from 1 to 10 MPa being preferred.

The copolymerization mixture may be agitated, e.g. by stirring, at a specific power input of typically 0.1-15 W/kg liquid phase, preferably 0.2-12 W/kg liquid phase in particular 0.5-10 W/kg liquid phase.

The polyketone copolymers of this invention have typically a limiting viscosity number (LVN) m the range of 0.1-5 dl/g, in particular 0.5-3 dl/g, based on viscosity measurements at 60 °C of solutions of the copolymers in m-cresol.

The polyketone copolymers obtained according to the invention are suitable as thermoplastics for fibres, filaments, films or sheets, or for injection moulding, compression moulding and blow moulding applications. They may be used for applications m the car industry, for the manufacture of packaging materials for food and drinks and for various uses in the domestic sphere.

The invention extends in a further aspect to a copolymer prepared by a process of the invention, as described herein.

The invention is now illustrated by means of the following example. The diluents were analytical grade chemicals, which were used as purchased. Example A linear alternating copolymer of carbon monoxide and ethene was prepared as follows.

A 2 litre experimental reactor was charged with a methanol/water solution (250 g water, 250 g methanol) containing the catalyst, with dodecane (490 g) and with an alcohol ethoxylate surfactant DOBANOL 45-7 (10 g. ex. Shell, an n-C]_4_-]_5 alkanol ethoxylate with 7 ethylene oxide units on average) . The catalyst was palladium acetate; 1, 3-bis [bis (ortho-methoxyphenyl) -phosphino] - propane; and tris (pentafluorophenyl) borane, the molar ratio of the catalyst components being 1; 1.1; 10. The concentration of palladium on the water/methanol blend was 10 ppm by weight. The mixture was stirred for 5 minutes with a specific power input of about 3 W/kg liquid phase. The turbid emulsion formed remained stable without further stirring for more than 5 minutes at ambient temperature, and also at 80 °C . The emulsion was of methanol/water droplets, containing the catalyst, suspended in the continuous dodecane phase. The average droplet size at ambient temperature measured by NMR, was 28 μm. The reactor was heated to 80 °C and then pressurized with 25 bar pressure of ethylene, and 25 bar pressure of carbon monoxide. The reactor content was stirred throughout with a specific power input of about 3 W/kg liquid phase. The rate of formation of the copolymer was approximately 8 kg copolymer/ (g palladium, hour) initially, dropping after about 30 minutes to a steady 2 kg copolymer/g palladium hour. The reaction time was about 2 hours. Throughout the reaction time the reaction mixture was well stirrable. At the end of the process the emulsion was broken (flocculated) by addition of 500 g acetone and subsequent heating. The slurry thus obtained was filtered and dried. The copolymer powder obtained has a bulk density of 250 kgm^~3, a melting point of 260 °C and an LVN of 1.0 dl/g.

Before the emulsion polymerization described above was conducted, a trial slurry polymerization had been carried out in a blend of methanol and water (both 50% by weight) to certify the catalyst performance m such a mixture. The same catalytic activity as for the conventional slurry polymerization carried out in pure methanol was found, and so the emulsion polymerization could be proceeded with.

Claims

C L A I M S

1. A process for the preparation of a linear alternating polyketone copolymer, from carbon monoxide and an olefinically unsaturated compound, comprising copolymerizing the monomers in the presence of a suitable catalyst composition, characterized in that the process is carried out in a reaction mixture which comprises a polar phase and an apolar phase, said apolar phase being a continuous phase, and the catalyst composition and the copolymer formed being retained in said polar phase.

2. A process as claimed in claim 1, wherein the polar phase is a discontinuous phase.

3. A process as claimed in claim 2, wherein the polar phase is dispersed within the apolar phase as droplets of average diameter in the range of 5 nm to 500 μm (measured at ambient temperature) .

4. A process as claimed in claim 3, wherein the average diameter of the droplets is in the range of 100 nm to

10 μm.

5. A process as claimed in any preceding claim, wherein the proportion by volume of the apolar phase to the polar phase is in the range 30-70 : 70-30.

6. A process as claimed in any preceding claim, wherein the polar phase comprises a first polar compound and a second polar compound, being liquids miscible with each other.

7. A process as claimed in any preceding claim, wherein the polar phase comprises a monohydric or polyhydric alcohol, a ketone or a halogenated hydrocarbon.

8. A process as claimed in claim 7, wherein the polar phase comprises a monohydric C^*ι -4 alcohol.

9. A process as claimed in any preceding claim, wherein the polar phase comprises methanol and water, the proportion by volume thereof being in the range 30-70 : 70-30.

10. A process as claimed in any preceding claim, wherein the apolar phase comprises a Cg_20 alkane.