KR20090071682A - Process for producing polyketone - Google Patents

Abstract

A process for producing polyketone is provided to improve catalyst activation and inherent viscosity by adding an oleic acid in polymerization in a condition of short polymerization time and using two kinds of acids having pKa of 4 or less as a catalyst component. A process for producing polyketone comprises a step of manufacturing the polyketone by copolymerizing carbon monoxide and ethylenically unsaturated compound in a liquid medium in the presence of an organometallic complex catalyst. The organometallic complex catalyst comprises (a) transition metal compound of Group 9, 10 or 11, (b) a ligand having elements of Group 15, and (c) anion of acid having pKa of 4 or less.

Description

Process for producing Polyketone

The present invention relates to a method for producing a polyketone with improved catalytic activity and intrinsic viscosity. More specifically, it is used as a catalyst component by mixing two kinds of acids having a pKa of 4 or less, and using oleic acid during polymerization under a short polymerization time. The present invention relates to a method for producing a polyketone having improved catalytic activity and intrinsic viscosity.

Copolymers of carbon monoxide with ethylenically unsaturated compounds, in particular polyketones having a structure in which a repeating unit derived from carbon monoxide and a repeating unit derived from an ethylenically unsaturated compound are alternately connected, have excellent mechanical and thermal properties, and are excellent in wear resistance and chemical resistance. It has high gas barrier properties and is a useful material for various applications. Moreover, the high molecular weight of the fully alternating polyketone is considered to be useful as an engineering plastic material having higher mechanical and thermal properties and excellent economical efficiency. In particular, the wear resistance is high, and parts such as automobile gears and chemical resistance are high, and the gas barrier property, such as lining material of chemical transport pipe, is high, so that it can be used for light gasoline tanks and the like. In addition, when the ultrahigh molecular weight polyketone having an intrinsic viscosity of 2 or more is used for the fiber, it is possible to stretch at high magnification, and to manufacture a fiber having high strength and high elastic modulus oriented in the stretching direction, and the fiber may be a belt or a rubber hose. This material is very suitable for building materials and industrial materials such as tire reinforcement, tire cord and concrete reinforcement.

As a method for obtaining a high molecular weight polyketone exhibiting high mechanical and thermal properties, European Patent No. 319083 discloses palladium, 1,3-bis [di (2-methoxyphenyl] phosphino] propane and an anion. A method of polymerizing at a low temperature using a catalyst is disclosed in Japanese Patent Laid-Open No. 4-227726, which discloses palladium and 2- (2,4,6-trimethylbenzene) -1,3-bis [di (2- Japanese Unexamined Patent Publication No. 5-140301 discloses a method of using a catalyst composed of methoxyphenyl) phosphino] propane and an anion, with palladium and 2-hydroxy-1,3-bis [di (2-methoxyphenyl) force. A method using a catalyst consisting of pino] propane and an anion has been disclosed, however, these methods have been economically problematic because the yield of polyketone per catalyst is low and the method of synthesizing the phosphorus ligand is difficult and expensive. .

As a method of obtaining a high molecular weight polyketone using a cheap catalyst, Japanese Patent Laid-Open No. 6-510552 uses a catalyst consisting of palladium, 1,3-bis (diphenylphosphino) propane and an anion of boron fluoride. To disclose polymerization in a tert-butanol solvent. According to this method, although a high molecular weight polyketone is obtained, there is a problem that the yield of polyketone per catalyst is very low, resulting in a high cost of polyketone.

As a method of economically obtaining high molecular weight polyketone with a high yield, Japanese Patent Laid-Open No. 8-283403 discloses a method of polymerization in a mixed solvent of methanol and 1 to 50% by volume of water. In this method, a catalyst consisting of a Group 10 metal source such as palladium, 1,3-bis (diphenylphosphino) propane and an anion of an inorganic acid is used. Particularly, when using palladium acetate, 1-3-bis (diphenylphosphino) propane and phosphorus tungstic acid in a methanol solvent containing 17% by volume of water, the temperature was 30 at 85 ° C and 4.8 MPa in a molar mixed gas such as ethylene and carbon monoxide. By the time of the polymerization reaction, a polymer having an intrinsic viscosity of 1.36 was obtained, and the catalytic activity at that time was 5.7 kg / g-Pdhr. If sulfuric acid is used instead of phosphorus tungstic acid in the mixed solvent, the catalytic activity is 9.5 kg / g-Pdhr. According to this method, although a high molecular weight polyketone is obtained by high catalyst activity, even if lengthening superposition | polymerization time is long, there existed a problem that it was impossible to obtain the polymer with the intrinsic viscosity 2 or more required in order to make a high performance material.

       European Patent No. 0361584, filed by Shell, discloses a process for polymerization at low pressure using trifluoroacetic acid in palladium and 1,3-bis (diphenylphosphino) propane. According to this method, a polymer having a catalyst activity of 1.3 kg / g-Pdhr intrinsic viscosity of 1.8 can be obtained by polymerization of 5.2 hours at 4 MPa at an input ratio of 1: 2 of ethylene and carbon dioxide at 50 ° C. According to this method, polyketone can be obtained under relatively low temperature and low pressure, but it is impossible to obtain polyketone having high intrinsic viscosity required for high performance materials.

Asahi of Japan used sulfuric acid as an inorganic acid in JP2002-317044 in a catalyst system similar to the prior art. The intrinsic viscosity was 6.45 in a 30 minute polymerization reaction of a Group 10 metal source such as palladium and 1,3-bis (diphenylphosphino) propane in a methanol solvent at 80 DEG C and 5.5 MPa of ethylene and carbon monoxide equimolar mixed gas. Phosphorus polymer was obtained, and the catalytic activity at that time was 6.0 kg / g-Pdhr.

As described above, in the method for producing polyketone using carbon monoxide and ethylenically unsaturated compound as a raw material, not only has high catalytic activity but also has a high intrinsic viscosity suitable for use for tire cords. Development is desired.

The present invention is to solve the problems of the prior art as described above, an object of the present invention is to use a mixture of two kinds of acid having a pKa of 4 or less as a catalyst component, and by adding oleic acid during polymerization, catalytic activity even under short polymerization time conditions And to provide a method for producing a polyketone with improved intrinsic viscosity

The process for producing the polyketone of the present invention comprises (a) a Group 9, 10 or 11 transition metal compound, (b) a ligand having an element of Group 15 and (c) an anion of an acid having a pKa of 4 or less. In the method of preparing a polyketone by copolymerizing carbon monoxide and an ethylenically unsaturated compound in a liquid medium in the presence of an organometallic complex catalyst which is formed, two kinds of acids having a pKa of 4 or less are mixed and used as the component (c). Is 1 to 2 hours and is characterized by adding oleic acid during polymerization.

In the present invention, the catalyst is a ligand having an element of (a) Group 9, Group 10 or Group 11 transition metal compound of the Periodic Table (IUPAC Inorganic Chemical Nomenclature, 1989), (b) Group 15 and (c) ) pKa is made up of an anion of an acid of 4 or less.

Examples of the Group 9 transition metal compound in the Group 9, 10 or 11 transition metal compound (a) include complexes of cobalt or ruthenium, carbonates, phosphates, carbamate salts, sulfonates, and the like. Specific examples thereof include cobalt acetate, cobalt acetylacetate, ruthenium acetate, trifluoro ruthenium acetate, ruthenium acetylacetate, and trifluoromethane sulfonic acid ruthenium.

Examples of the Group 10 transition metal compound include a complex of nickel or palladium, carbonate, phosphate, carbamate, sulfonate, and the like, and specific examples thereof include nickel acetate, nickel acetyl acetate, palladium acetate, and palladium trifluoroacetate. , Palladium acetylacetate, palladium chloride, bis (N, N-diethylcarbamate) bis (diethylamine) palladium, palladium sulfate and the like.

Examples of the Group 11 transition metal compound include copper or silver complexes, carbonates, phosphates, carbamates, sulfonates, and the like, and specific examples thereof include copper acetate, trifluoro copper acetate, copper acetylacetate, silver acetate, Trifluoro silver acetate, silver acetyl acetate, silver trifluoromethane sulfonic acid, etc. are mentioned.

Among these, inexpensive and economically preferable transition metal compounds (a) are nickel and copper compounds, and preferred transition metal compounds (a) are palladium compounds in terms of yield and molecular weight of polyketones, and in terms of improving catalytic activity and intrinsic viscosity. Most preferably, palladium acetate is used in the process.

Examples of the ligand (b) having a group 15 atom include 2,2'-bipyridyl, 4,4'-dimethyl-2,2'-bipyridyl, 2,2'-bi-4-picolin , Nitrogen ligands such as 2,2'-bikinolin, 1,2-bis (diphenylphosphino) ethane, 1,3-bis (diphenylphosphino) propane, 1,4-bis (diphenylphosphino) Butane, 1,3-bis [di (2-methyl) phosphino] propane, 1,3-bis [di (2-isopropyl) phosphino] propane, 1,3-bis [di (2-methoxyphenyl ) Pinospino] propane, 1,3-bis [di (2-methoxy-4-sulfonic acid-phenyl) phosphino] propane, 1,2-bis (diphenylphosphino) cyclohexane, 1,2-bis (Diphenylphosphino) benzene, 1,2-bis [(diphenylphosphino) methyl] benzene, 1,2-bis [[di (2-methoxyphenyl) phosphino] methyl] benzene, 1,2- Bis [[di (2-methoxy-4-sulfonate-phenyl) phosphino] methyl] benzene, 1,1'-bis (diphenylphosphino) ferrocene, 2-hydroxy-1,3-bis [di (2-methoxyphenyl) phosphino] propane, 2,2-dimethyl-1,3-bis [di (2-meth When there may be mentioned a ligand such as phenyl) phosphino] propane.

Among them, the ligand (b) having an element of Group 15 is a phosphorus ligand having an atom of Group 15, and particularly, in view of the yield of polyketone, a phosphorus ligand is preferably 1,3-bis [di (2- Methoxyphenyl) phosphino] propane, 1,2-bis [[di (2-methoxyphenyl) phosphino] methyl] benzene, and 2-hydroxy-1,3-bis [in terms of molecular weight of the polyketone. Di (2-methoxyphenyl) phosphino] propane, 2,2-dimethyl-1,3-bis [di (2-methoxyphenyl) phosphino] propane, and do not require an organic solvent in terms of safety Water-soluble 1,3-bis [di (2-methoxy-4-sulfonate-phenyl) phosphino] propane, 1,2-bis [[di (2-methoxy-4-sulfonate-phenyl) phosphino ] Methyl] benzene, the synthesis | combination is easy, it is available in large quantities, and economically preferable is 1, 3-bis (diphenyl phosphino) propane and 1, 4-bis (diphenyl phosphino) butane.

In the present invention, which focuses on the intrinsic viscosity and catalytic activity of the polyketone, the ligand (b) having a group 15 atom is preferably 1,3-bis [di (2-methoxyphenyl) phosphino] propane or 1,3-bis (diphenylphosphino) propane, most preferably 1,3-bis [di (2-methoxyphenyl) phosphino] propane.

The amount of the Group 9, Group 10 or Group 11 transition metal compound (a) used is limited because the appropriate value varies depending on the type of the ethylenically unsaturated compound selected or other polymerization conditions. Although not possible, it is usually 0.01-100 mmol, preferably 0.01-10 mmol, per liter of the capacity of the reaction zone. The capacity of the reaction zone means the capacity of the liquid phase of the reactor.

Examples of the anion (c) of an acid having a pKa of 4 or less include anions of an organic acid having a pKa of 4 or less, such as trifluoroacetic acid, trifluoromethane sulfonic acid, and p-toluene sulfonic acid; Anions of inorganic acids having a pKa of 4 or less, such as perchloric acid, sulfuric acid, nitric acid, phosphoric acid, heteropoly acid, tetrafluoroboric acid, hexafluorophosphoric acid, and fluorosilicic acid; And anions of boron compounds such as trispentafluorophenylborane, trisphenylcarbenium tetrakis (pentafluorophenyl) borate, and N, N-dimethylarinium tetrakis (pentafluorophenyl) borate.

The present invention is different from the prior art in which an acid having a pKa of 4 or less is used alone in a catalyst used in the preparation of a polyketone, and a mixture of two acids having a pKa of 4 or less is used. In the present invention, it is possible to achieve the effect of improving the intrinsic viscosity of the polyketone by using two kinds of acids having a pKa of 4 or less. Among the acids having a pKa of 4 or less, trifluoroacetic acid and p-toluene sulfonic acid or trifluoroacetic acid and sulfuric acid are mixed and used most preferably in terms of improving intrinsic viscosity.

In this invention, it is preferable that the molar ratios of the said (a) component: (b) component: (c) component are 1: 1: 1: 5-20. In particular, the molar ratio of 1: 1.2: 7 showed the best catalytic activity and intrinsic viscosity. Generally, in the prior art, the molar ratio of (a) component: (b) component: (c) component is 1: 1.2: 20, and the amount of acid addition is large.However, an acid having a pKa of 4 or less is used as (c) component. In the present invention using two kinds of mixtures, it was found that polyketones having the most satisfactory catalytic activity and intrinsic viscosity can be obtained when the ratio is 1: 1.2: 7. In the present invention, by adjusting the molar ratio of component (a) to component (b): component (c) to 1: 1.2: 7, the catalytic activity and intrinsic viscosity of the polyketone can be improved and economic benefits can be achieved.

The present invention is another feature of the addition of oleic acid during the polymerization of polyketone. In the present invention, it is possible to achieve the effect of improving the intrinsic viscosity of the polyketone by adding oleic acid during the polymerization of the polyketone.

The molar ratio of the (a) Group 9, Group 10 or Group 11 transition metal compound and oleic acid is 1: 0.1-20, preferably 1: 0.1-10, most preferably 1: 0.1-5. When the amount of oleic acid added is large, the catalytic activity tends to decrease.

In the present invention, examples of the ethylenically unsaturated compound copolymerized with carbon monoxide include ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1 Α-olefins such as tetradecene, 1-hexadecene and vinylcyclohexane; Alkenyl aromatic compounds such as styrene and α-methylstyrene; Cyclopentene, norbornene, 5-methylnorbornene, 5-phenylnorbornene, tetracyclododecene, tricyclododecene, tricycloundecene, pentacyclopentadecene, pentacyclohexadecene, 8-ethyltetra Cyclic olefins such as cyclododecene; Vinyl halides such as vinyl chloride; Acrylic esters, such as ethyl acrylate and methyl acrylate, etc. are mentioned. These ethylenically unsaturated compounds are used individually or in mixture of multiple types. Preferred ethylenically unsaturated compounds among these are α-olefins, more preferably α-olefins having 2 to 4 carbon atoms, and most preferably ethylene.

In the present invention, it is preferable to adjust the input ratio of carbon monoxide and ethylenically unsaturated compound to 1: 1.8. In the production of polyketone, it is common to set the ratio of carbon monoxide and ethylenically unsaturated compound to 1: 1, but in the present invention in which two kinds of acids having a pKa of 4 or less are mixed and used, and oleic acid is added during polymerization, carbon monoxide and ethylenic It was found that setting the ratio of the unsaturated compound to 1: 1.8 can simultaneously achieve the improvement of the catalytic activity and the intrinsic viscosity.

The present invention is further characterized by using a mixed solvent comprising a water-soluble organic solvent and 500 to 5000 ppm water as a liquid medium. If the water is less than 500ppm or more than 5000ppm there is a problem that the catalytic activity is sharply reduced.

Specific examples of the water-soluble organic solvent that can be used in the present invention include alcohols such as methanol, ethanol, propanol, butanol, hexafluoroisopropanol and ethylene glycol; phenols such as m-cresol; Amines such as aniline; Ketones such as acetone and methyl ethyl ketone; Ethers such as diethyl ether, tetrahydrofuran and diglyme; Nitriles such as acetonitrile; Ester, such as acetic acid and methyl acetate, etc. are mentioned, These are used individually or as mixed solvent of multiple types. From the viewpoint of economy and safety of handling, preferred water-soluble organic solvents are alcohols, and more preferably methanol.

In the present invention, two kinds of acids having a pKa of 4 or less are mixed and used, and the addition of oleic acid during polymerization not only improves the catalytic activity and intrinsic viscosity of the polyketone, but also in the prior art, a polymerization time of at least 10 is improved to improve intrinsic viscosity. Unlike the time required to be more than the time, it was confirmed that the production of polyketone having a high intrinsic viscosity even with a polymerization time of about 2 hours.

In the present invention, the copolymerization of carbon monoxide and the ethylenically unsaturated compound includes the Group 9, Group 10 or Group 11 transition metal compound (a), the ligand (b) having an element of Group 15 and pKa of 4 It occurs by the organometallic complex catalyst which consists of the anion (c) of the following acid, and this catalyst is produced by contacting the said three components. Arbitrary methods can be employ | adopted as a method of making it contact. That is, you may make and use the solution which mixed three components previously in a suitable solvent, and may respectively supply three components separately to a polymerization system, and may contact them in a polymerization system. Preferably, the mixing of the components (a) (b) and (c) is performed simultaneously.

In carrying out the present invention, as the polymerization method, a solution polymerization method using a liquid medium, a suspension polymerization method, a gas phase polymerization method in which a small amount of polymer is impregnated with a high concentration of a catalyst solution are used. The polymerization may be either batchwise or continuous. The reactor used for superposition | polymerization can use a well-known thing as it is or processing it. There is no restriction | limiting in particular about polymerization temperature, Generally 40-180 degreeC, Preferably 50-120 degreeC is employ | adopted. Although there is no restriction | limiting also about the pressure at the time of superposition | polymerization, Usually, it is normal pressure-20 MPa, Preferably it is 4-15 MPa.

According to the present invention, there is provided a method for producing a polyketone in which two kinds of acids having a pKa of 4 or less are mixed and used as a catalyst component and oleic acid is added during polymerization to improve catalytic activity and intrinsic viscosity.

Hereinafter, the structure and effect of the present invention will be described in more detail with specific examples and comparative examples, but these examples are only intended to more clearly understand the present invention, and are not intended to limit the scope of the present invention. Intrinsic viscosity and catalytic activity of polyketone in Examples and Comparative Examples were evaluated by the following method.

(1) intrinsic viscosity

Melt the polymerized resin at a concentration of 0.01g / 100ml ~ 1g / 100ml (m-cresol) for about 1-5 hours in a 60 ^° C thermostat and measure the viscosity at 30 ^° C using a Ubelode viscometer. Plot the viscosity according to the concentration and extrapolate to find the intrinsic viscosity.

(2) catalytic activity

The amount of polymerized resin / palladium is determined by the amount of time (kg / g-Pdhr).

(Example 1)

0.0142 g of palladium acetate, 0.0320 g of 1,3-bis [di (2-methoxyphenyl] phosphino] propane, 0.0200 g of trifluoroacetic acid and 0.0333 g of p-toluene sulfonic acid were dissolved in 100 ml of Acetone with 0.5649 g of oleic acid. The solution was dissolved in a mixed solvent of 2497.5 ml of methanol and 2.5 ml of water, and the solution was evacuated by vacuum, and then charged into a nitrogen-substituted stainless autoclave. The mixture was warmed with stirring at a rate of, and when the internal temperature reached 70 ° C., a 1: 1.8 mixed gas of carbon monoxide and ethylene was added until the autoclave internal pressure became 70 bar, while maintaining the internal temperature at 70 ° C. and internal pressure at 70 bar, 2 The stirring was continued for a while After cooling, the gas in the autoclave was purged and the contents were taken out The reaction solution was filtered, washed several times with methanol, and dried under reduced pressure at room temperature to 80 DEG C to obtain 114.18 g of a polymer.

^{From 13} C-NMR and IR results, it was confirmed that this polymer was a polyketone consisting essentially of a repeating unit derived from carbon monoxide and a repeating unit derived from ethylene. The catalytic activity was 8.3 kg / gPdhr and the intrinsic viscosity was high value of 13.2 dl / g.

A summary of these results is shown in Table 1 below.

(Example 2)

0.0142 g of palladium acetate, 0.0320 g of 1,3-bis [di (2-methoxyphenyl] phosphino] propane, 0.0249 g of trifluoroacetic acid and 0.0172 g of p-toluene sulfate were dissolved in 100 ml of Acetone with 0.5649 g of oleic acid. The solution was dissolved in a mixed solvent of 2497.5 ml of methanol and 2.5 ml of water, and the solution was evacuated by vacuum, then charged into a nitrogen-substituted stainless autoclave. The mixture was warmed with stirring at a rate of, and when the internal temperature reached 70 ° C., a 1: 1.8 mixed gas of carbon monoxide and ethylene was added until the autoclave internal pressure became 70 bar, while maintaining the internal temperature at 75 ° C. and internal pressure at 70 bar, 2 The stirring was continued for a while After cooling, the gas in the autoclave was purged and the contents were taken out The reaction solution was filtered, washed several times with methanol, and dried under reduced pressure at room temperature to 80 DEG C to obtain 138.52 g of a polymer.

^{From 13} C-NMR and IR results, it was confirmed that this polymer was a polyketone consisting essentially of a repeating unit derived from carbon monoxide and a repeating unit derived from ethylene. The catalytic activity was 10.1 kg / gPdhr and the intrinsic viscosity was high value of 11.7 dl / g.

A summary of these results is shown in Table 1 below.

(Comparative Example 1)

0.0142 g of palladium acetate, 0.0320 g of 1,3-bis [di (2-methoxyphenyl] phosphino] propane, 0.0200 g of trifluoroacetic acid and 0.0333 g of p-toluene sulfonic acid were dissolved in 100 ml of Acetone. It was dissolved in a mixed solvent of 2497.5 ml and 2.5 ml of water, and the solution was evacuated by vacuum, and then charged into a nitrogen-substituted stainless autoclave After closing the autoclave, the contents were stirred at a speed of 800 rpm. The mixture was warmed, and when the internal temperature reached 70 ° C., a 1: 1.8 mixed gas of carbon monoxide and ethylene was added until the autoclave internal pressure became 70 bar, while stirring was continued for 2 hours while maintaining the internal temperature at 70 ° C. and the internal pressure at 70 bar. After cooling, the gas in the autoclave was purged and the contents were taken out The reaction solution was filtered, washed several times with methanol, and dried under reduced pressure at room temperature to 80 ° C. to obtain 78.14 g of a polymer.

^{From 13} C-NMR and IR results, it was confirmed that this polymer was a polyketone consisting essentially of a repeating unit derived from carbon monoxide and a repeating unit derived from ethylene. The catalytic activity was equivalent to 5.7 kg / gPdhr and the intrinsic viscosity was high at 6.3 dl / g.

A summary of these results is shown in Table 1 below.

(Comparative Example 2)

0.0142 g of palladium acetate, 0.0320 g of 1,3-bis [di (2-methoxyphenyl] phosphino] propane, 0.0249 g of trifluoroacetic acid and 0.0172 g of p-toluene sulfuric acid were dissolved in 100 ml of Acetone. It was dissolved in a mixed solvent of 2497.5 ml and 2.5 ml of water, and the solution was evacuated by vacuum, and then charged into a nitrogen-substituted stainless autoclave After closing the autoclave, the contents were stirred at a speed of 800 rpm. The mixture was warmed, and when the internal temperature reached 70 ° C., a 1: 1.8 mixed gas of carbon monoxide and ethylene was added until the autoclave internal pressure became 70 bar, while stirring was continued for 2 hours while maintaining the internal temperature at 70 ° C. and the internal pressure at 70 bar. After cooling, the gas in the autoclave was purged and the contents were taken out The reaction solution was filtered, washed several times with methanol, and dried under reduced pressure at room temperature to 80 ° C. to obtain 89.61 g of a polymer.

^{From 13} C-NMR and IR results, it was confirmed that this polymer was a polyketone consisting essentially of a repeating unit derived from carbon monoxide and a repeating unit derived from ethylene. The catalytic activity was equivalent to 65 kg / gPdhr, and the intrinsic viscosity was high value of 5.8 dl / g.

A summary of these results is shown in Table 1 below.

Table 1.

Claims (10)

in the presence of an organometallic complex catalyst comprising (a) a Group 9, 10 or 11 transition metal compound, (b) a ligand having an element of Group 15 and (c) an anion of an acid having a pKa of 4 or less, A method of producing a polyketone by copolymerizing carbon monoxide and an ethylenically unsaturated compound in a liquid medium, wherein (c) is used a mixture of two kinds of acids having a pKa of 4 or less and added oleic acid during polymerization. Method for preparing ketones. The method for producing polyketone according to claim 1, wherein the component (a) is palladium acetate. The method for producing a polyketone according to claim 1, wherein the component (b) is 1,3-bis [di (2-methoxyphenyl) phosphino] propane. The method for producing polyketone according to claim 1, wherein trifluoroacetic acid and p-toluene sulfonic acid are mixed and used as the component (c). The method for producing polyketone according to claim 1, wherein trifluoroacetic acid and sulfuric acid are mixed and used as the component (c). The method for producing polyketone according to claim 1, wherein the molar ratio of the component (a): (b) component: (c) is 1: 1.2: 7. The method for producing polyketone according to claim 1, wherein the molar ratio of component (a) to oleic acid is 1: 0.1 to 20. The method of claim 1, wherein the input ratio of the carbon monoxide and the ethylenically unsaturated compound is 1: 1.8. The method for producing polyketone according to claim 1, wherein a mixed solvent comprising a water-soluble organic solvent and 500 to 5000 ppm water is used as the liquid medium. 10. The method of claim 9, wherein the water soluble organic solvent is methanol.