WO2003085008A1 - Method of recovering catalyst from hydrogenation reaction mixture and process for producing hydrogenated conjugated diene polymer - Google Patents

Abstract

A method of catalyst recovery which comprises bringing a platinum element-containing catalyst contained in a hydrogenation reaction mixture into contact with an oxidizing agent to oxidize the catalyst, adding a complexing agent to the reaction mixture simultaneously with or after addition of the oxidizing agent to complex the catalyst, and separating out the complex yielded; and a process for producing a hydrogenated conjugated diene polymer which comprises: a reaction step (A) in which a conjugated diene polymer is hydrogenated in the presence of a platinum element-containing catalyst; an oxidation step (B) in which the catalyst contained in the reaction mixture is contacted with an oxidizing agent; a complexing step (C) in which a complexing agent is added to the resultant reaction mixture to yield a complex of the oxidized catalyst; and a catalyst recovery step (D) in which the complex yielded is separated from the reaction mixture which has undergone the complexing.

Description

 Description Method for recovering catalyst from hydrogenation reaction mixture and method for producing hydrogenated conjugated diene polymer

 The present invention relates to a method for recovering a hydrogenation catalyst contained in a hydrogenation reaction mixture and a method for producing a hydrogenated conjugated polymer. Background technology.

 In the chemical industry that manufactures pharmaceuticals, agrochemicals, petrochemicals, and polymers, a hydrogenation reaction that hydrogenates carbon-carbon unsaturated bonds and carbon-nitrogen unsaturated bonds contained in various compounds and converts them into the corresponding saturated bonds. Is widely practiced.

 For example, in the field of polymers, a method for selectively or partially hydrogenating a carbon-carbon double bond of a conjugated polymer is known as a useful means for modifying a conjugated gen-based polymer. Hydrogenated conjugated diene polymers such as lyl-butadiene copolymers are produced on an industrial scale.

As a typical process for producing such a hydrogenated conjugated polymer,

(1) A step of emulsion-polymerizing a monomer containing a conjugated gen and coagulating and drying the obtained latex to prepare a raw material polymer. (2) Dissolving the raw material polymer in an organic solvent (hydrogenation reaction solvent) Hydrogenating using a supported catalyst in which a platinum group element-containing catalyst is supported on a carrier that is insoluble in the organic solvent; (3) separating the supported catalyst from the hydrogenation reaction mixture, A process comprising recovering a polymerized polymer from an organic solvent is known.

 However, in the above processes (1) and (2), the raw material polymer once recovered from the latex of the conjugated gen-based polymer is pulverized and dissolved again in an organic solvent, and after the organic solvent is hydrogenated, A complicated operation such as distillation is required. In addition,

Depending on the preparation conditions of the supported catalyst used in (2), the support may be damaged during the hydrogenation reaction and the catalyst components may fall off the support. Even if the amount is separated and recovered, there is a problem that the recovery rate of the valuable and expensive catalyst containing a platinum group element is reduced.

 On the other hand, a process using an organic solvent-soluble unsupported catalyst without using a supported catalyst as described in (2) above, or a process using a supported or unsupported catalyst without going through the steps as described in (1) to (2) above. Various studies have been made on a process for directly hydrogenating a conjugated gen-based polymer in a latex state obtained by emulsion polymerization using a supported catalyst (for example, US Pat. No. 3,898,2). No. 08, 'Japanese Unexamined Patent Application Publication No. 2-178830).

 However, in a hydrogenation reaction in a latex state containing an aqueous medium, when a supported catalyst is used as in the above-described conventional process, the catalytic activity was not sufficiently satisfactory. In addition, when an unsupported catalyst that dissolves or disperses in an organic solvent or aqueous medium is used, it is extremely difficult to separate and recover the catalyst after the completion of the reaction. There was a problem of increasing. Disclosure of the invention

 In view of the above circumstances, an object of the present invention is to react the platinum group element-containing catalyst used in the hydrogenation reaction in the post-treatment stage of the hydrogenation reaction in hydride production, which is widely performed in various fields of the chemical industry. An object of the present invention is to provide a method for efficiently separating and recovering from a mixture.

 Another object of the present invention is to provide a method for producing a hydrogenated conjugated gen-based polymer, wherein the platinum group element-containing catalyst used in the hydrogenation reaction of the raw material polymer is prepared from a reaction mixture containing an organic solvent or an aqueous medium. An object of the present invention is to provide an industrially advantageous process for producing hydrogenated conjugated gen-based polymers that can be efficiently separated and recovered.

In order to solve the above-mentioned problems, the present inventors aimed at both a reaction system for hydrogenating a conjugated gen-based polymer (raw material) in a latex state and a reaction system for hydrogenating a conjugated gen-based polymer (raw material) in an organic solvent solution. After the completion of the reaction, the post-treatment method has been intensively studied. As a result, first, an oxidizing agent is added to the reaction mixture to oxidize the catalyst residue, and simultaneously or subsequently, a complexing agent is added to the reaction mixture to complex the catalyst residue. Found that the complex formed by this method can be separated efficiently. did.

 In addition, the improvement in the post-treatment method of the hydrogenation reaction as described above is applicable to not only (1) production of a hydrogenated polymer but also hydrogenation reactions in various fields; (2) hydrogenation reaction The catalyst containing the platinum group element used in the process can be easily recovered and reused, so even if a large amount of catalyst is used, there is no problem in economical efficiency, and the production of various hydrides, especially the production of hydrogenated conjugated gen-based polymers, is possible. (3) Since the amount of residual catalyst in the obtained hydride is small, there is little adverse effect on the quality of products containing the hydride; Thus, the present invention has been completed.

 Thus, according to the present invention, the platinum group element-containing catalyst contained in the hydrogenation reaction mixture is oxidized by bringing it into contact with an oxidizing agent, and is further added to the reaction mixture simultaneously with or after the addition of the oxidizing agent. A method for recovering a catalyst is provided, wherein a complexing agent is added to perform a complexing treatment, and a formed complex is separated.

 Further, according to the present invention, a reaction step (A) of hydrogenating the conjugated gen-based polymer in the presence of a platinum group element-containing catalyst; an oxidation treatment step of bringing the catalyst contained in the reaction mixture into contact with an oxidizing agent (B): a complexing treatment step of adding a complexing agent to the reaction mixture to form an oxidized catalyst complex (C); a catalyst recovery step (D) of separating the complex formed from the complexed reaction mixture ); Which provides a method for producing a hydrogenated conjugated gen-based polymer. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, a method for recovering the hydrogenation catalyst contained in the hydrogenation reaction mixture and a method for producing the hydrogenation co-polymer are described in detail.

 In the catalyst recovery method of the present invention, the catalyst containing the platinum group element contained in the hydrogenation reaction mixture is oxidized by bringing it into contact with an oxidizing agent, and further, a complexing agent is added to the reaction mixture to perform complexing. It is characterized in that the formed complex is separated.

The catalyst recovery method of the present invention uses a platinum group element-containing catalyst in the fields of manufacturing pharmaceuticals, agricultural chemicals, industrial chemicals, petroleum, petrochemicals, polymer products, fats and oils, edible oils, lubricants, fragrances, and the like. It is widely applicable when performing hydrogenation reactions, The medium (catalyst residue) can be efficiently recovered from the reaction mixture.

 The hydrogenation reaction mixture to which this method can be applied is not particularly limited as long as it is a mixture obtained by performing a hydrogenation reaction in the presence of a platinum group element-containing catalyst. Such hydrogenation reactions include, for example, the partial hydrogenation of acetylene to ethylene, the partial hydrogenation of 3-hexene-1 to cis-13-hexene1-1-ol. Hydrogenation of acetylene bond to carbon-carbon double bond; hydrogenation of gasoline (improvement of gasoline quality), production of isooctane from diisobutylene, production of saturated dalyceride from unsaturated glyceride, conjugation Hydrogenation of carbon-carbon double bonds to saturated bonds, typically represented by the production of hydrogenated conjugated gen-based polymers from benzene-based polymers; carbonyl to produce the corresponding alcohol from cyclopentanone / cyclohexanone Hydrogenation of a group; a hydrogenation reaction of converting a nitrile group or an azomethine group (Schiff base) into an amino group; and the like.

 Among the various hydrogenation reactions described above, the catalyst recovery method of the present invention is particularly preferably applicable to the method for producing a hydrogenated conjugated gen-based polymer according to another invention of the present invention. Hereinafter, the specific embodiment will be described.

 The method for producing a hydrogenated conjugated polymer according to the present invention comprises: a reaction step (A) of hydrogenating the conjugated polymer in the presence of a platinum group element-containing catalyst; (B); a complexing step of adding a complexing agent to the reaction mixture to form an oxidized catalyst complex (C); a complex formed from the complexed reaction mixture It is essential to include a catalyst recovery step (D); The above-described reaction step (A :), oxidation treatment step (B), complexation treatment step (C), and catalyst recovery step (D) are performed in this order, but other treatment steps may be added if desired. Can be added. Step (B) and step (C) can be performed simultaneously. In addition, the catalyst recovered in the step (D) can be purified or regenerated as required, and then can be reused in the step (A).

The hydrogenation in the reaction step (A) means that at least a part of the carbon-carbon double bond contained in the conjugated polymer is hydrogenated to be converted into a saturated bond. The conjugated gen-based polymer applied in this step (A) may contain at least one kind of conjugated gen monomer or at least one kind of monomer copolymerizable with the conjugated gen monomer. Mers 1 It is produced by a conventionally known emulsion polymerization method or solution polymerization method, preferably by an emulsion polymerization method, in combination with one or more kinds.

 The conjugated diene monomer is not particularly limited as long as it is a polymerizable monomer having a conjugated diene structure. For example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2, Examples include 3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, and 1,3-pentene. Of these, 1,3-butadiene and 2-methyl-1,3-butadiene are preferred, and "1,3-butanediene is more preferred.

 Examples of monomers copolymerizable with the conjugated diene monomer include α,] 8-ethylenically unsaturated nitrile monomers such as acrylonitrile, methacrylonitrile, and croton nitrile; <X, / 3-ethylenically unsaturated carboxylic acids such as acid, methacrylic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid; methyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, triflu A, 3-ethylenically unsaturated carboxylic acid esters such as loethyl acrylate and methyl methacrylate; α, β-ethylenically unsaturated carboxylic acid amides such as acrylamide and methacrylamide; styrene, α-methylstyrene, ρ- Vinyl aromatic compounds such as methyl styrene and divinylbenzene; vinyl acetate, vinyl acetate Binirue one ether compound such as a full year old Roe chill ether; vinyl esters such as and the like.

 Among these monomers copolymerizable with the conjugated diene monomer, a monomer having an electron-withdrawing functional group is preferable from the viewpoint that the hydrogenation reaction in the step (Α) proceeds smoothly. j8—Ethylenically unsaturated nitrile monomer, especially acrylonitrile, is preferably used.

 The monomer composition ratio in the conjugated diene polymer is not particularly limited, but is preferably 5 to 100% by weight of the conjugated diene monomer and 95 to 0% by weight of a monomer copolymerizable therewith. In other words, it is 10 to 90% by weight of a conjugated diene monomer and 90 to 10% by weight of a monomer copolymerizable therewith.

Specific examples of the conjugated gen-based polymer applied to the hydrogenation in the step (A) include butadiene polymer, isoprene polymer, butadiene-styrene copolymer, and acrylonitrile. Tolyl-butadiene copolymer, acrylonitrile-isoprene copolymer, acrylonitrile-butadiene-isoprene copolymer, methacrylonitrile-butadiene copolymer, methyl acrylonitrile-isoprene copolymer, methacrylonitrile Tributyl-butadiene-isoprene copolymer, acrylonitrile-methacrylonitrile-butadiene copolymer, acrylonitrile-butadiene-methyl acrylate copolymer, acrylonitrile-butadiene-acrylic acid copolymer, and the like. It is possible.

 Among the above conjugated gen-based polymers, acrylonitrile-1,3-butadiene copolymer and methacrylonitrile-11,3-butadiene copolymer are preferred from the viewpoint of practicality and versatility as a raw material for producing a hydrogenated copolymer. Coalescence is preferred. In particular, 30 to 95% by weight of Ί, 3-butadiene, preferably 45 to 85% by weight, and 5 to 70% by weight of acrylonitrile, preferably Ί5 to 55% by weight. Polymers are preferred.

 The weight-average molecular weight (gel permeation 'chromatography method, standard polystyrene conversion) is not particularly limited, but is usually determined to be 5,000 to 50,000, 000.

 Emulsion polymerization, which is suitable for preparing a conjugated diene polymer (raw material), is generally carried out in an aqueous medium using a radical polymerization initiator, and a known polymerization initiator and molecular weight regulator are used. Just use it. The polymerization reaction may be any of a batch system, a semi-batch system, and a continuous system, and the polymerization temperature and pressure are not particularly limited. The emulsifier to be used is not particularly limited. Anionic surfactants, surfactants, amphoteric surfactants, nonionic surfactants, and the like can be used, but anionic surfactants are preferred. . These emulsifiers may be used alone or in combination of two or more. The amount used is not particularly limited.

 The solid content concentration of the conjugated polymer latex obtained by emulsion polymerization is not particularly limited, but is usually 2 to 70% by weight, preferably 5 to 60% by weight. The concentration of the solid component can be appropriately adjusted by a known method such as a blending method, a dilution method, and a concentration method.

The hydrogenation reaction in step (Α) is performed in latex state (hereinafter referred to as “latex hydrogenation”). Also say. ), It is more preferable to adjust the solid content of the latex to be in the range of 10 to 50% by weight from the viewpoint of reaction efficiency.

 In the hydrogenation reaction in the step (A), a conjugated polymer rubber obtained by coagulating and drying a latex obtained by emulsion polymerization is dissolved in an appropriate organic solvent in a state of a polymer solution (hereinafter referred to as “solution system”). Hydrogenation ”).

 In this case, the coagulation and drying of the latex may be performed by a known method, but by providing a treatment step of bringing the crumb obtained by coagulation into contact with a basic aqueous solution, the obtained conjugated gen-based polymer rubber can be treated with tetrahydrofuran. It is preferable to modify the polymer solution to be dissolved in (THF) so that the pH of the polymer solution measured is more than 7. The pH of the polymer solution, as measured in solution in THF, is preferably from 7.2 to 12, more preferably from 7.5 to 11.5, most preferably from 8 to 1%. By the contact treatment between the crumb and the basic aqueous solution, solution-based hydrogenation can be promptly advanced.

 The solution concentration of the conjugated gen-based polymer in the solution hydrogenation is 1 to 70% by weight, preferably 2 to 40% by weight. Examples of the organic solvent used for the solution-based hydrogenation include linear or cyclic aliphatic hydrocarbons such as n-hexane, cyclohexane, and n-hexane; benzene, toluene, xylene, and chlorobenzene. Aromatic hydrocarbons; ketones such as acetone, methyl ethyl ketone, getyl ketone, methyl isopropyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone; getyl ether, tetrahydrofuran Ethers such as dioxane and benzoyl; esters such as ethyl acetate; and the like. Among these organic solvents, ketones are preferably used.

 The catalyst used in the hydrogenation reaction in step (A) is a hydrogenation catalyst containing a platinum group element (ruthenium, rhodium, palladium, osmium, iridium or platinum). As the hydrogenation catalyst, a palladium compound and a rhodium compound are preferable from the viewpoint of catalytic activity and availability, and a palladium compound is more preferable. Further, two or more platinum group element compounds may be used in combination, but also in this case, it is preferable to use a palladium compound as a main catalyst component.

A palladium compound as a hydrogenation catalyst is not particularly limited as long as it has catalytic activity. Not limited. Usually, a valence II or valence IV palladium compound is used, and its form is a salt / complex.

 Examples of the palladium compound include organic acid salts such as palladium acetate and palladium cyanide; halides such as palladium fluoride, palladium chloride, palladium bromide, and palladium iodide; oxyacid salts such as palladium nitrate and palladium sulfate; Palladium oxide; Palladium hydroxide; Palladium compounds such as dichloro (cyclopentadiene) palladium, dichloro (norbornadiene) palladium, dichlorobis (triphenylphosphine) palladium, sodium palladium tetrachloride, and ammonium hexachloropalladium; Complex salts such as potassium trasianopalladate; and the like.

 Among these palladium compounds, palladium acetate, palladium nitrate, palladium sulfate, palladium chloride, sodium tetrachloroporate, and ammonium hexachloropalladate are preferred, and palladium acetate, palladium nitrate and palladium chloride are more preferred.

 The rhodium compound as the hydrogenation catalyst is not particularly limited as long as it has catalytic activity. For example, halogenated compounds such as rhodium chloride, rhodium bromide and rhodium iodide; inorganic acids such as rhodium nitrate and rhodium sulfate Salts; Organic acid salts such as rhodium acetate, rhodium formate, rhodium propionate, rhodium butyrate, rhodium oxyacid, rhodium naphthenate, rhodium acetylacetonate; rhodium oxide; rhodium trihydroxide And the like.

 The hydrogenation catalyst can be used as an unsupported catalyst in which the catalyst component is directly dissolved or dispersed in the reaction system without being supported on a carrier. Further, it can be used as a supported catalyst in which a catalyst component is supported on a support and charged into a reaction system. Further, supported and non-supported catalysts can be used in combination.

As the carrier of the supported catalyst, a known catalyst carrier such as activated carbon, activated clay, alumina gel, silica gel, and diatomaceous earth is used. Examples of a method for supporting the catalyst component on a carrier include an impregnation method, a coating method, a spray method, an adsorption method, and a precipitation method. The supported amount of the catalyst component is usually 0.5 to 80% by weight, preferably 1 to 50% by weight, more preferably 2 to 30% by weight. The carrier supporting the catalyst component reacts Depending on the type of vessel and reaction type, it can be formed into, for example, a spherical shape, a cylindrical shape, a polygonal column shape, an 82-cam shape, and the like. The supported catalyst may be added as it is to the latex or solution hydrogenation reaction system.

 As a method for adding the unsupported catalyst to both reaction systems described above, a method of directly adding and then dissolving or dispersing in the reaction system; dissolving or dispersing in water or an organic solvent in advance and preparing a catalyst solution state A method of adding to a reaction system; In the latter method, particularly when an aqueous catalyst solution is prepared, for example, inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, bromic acid, perchloric acid, and phosphoric acid; sodium salts and potassium salts of these inorganic acids; and organic acids such as acetic acid And coexistence thereof may improve the solubility in water, which is preferable in some cases. Furthermore, when an unsupported medium is applied to latex-based hydrogenation, it is soluble or dispersible in latex as a hydrogenation catalyst stabilizer in order to maintain the stability of the platinum group element-containing catalyst in the latex. A high molecular weight compound having a weight average molecular weight of preferably 1,000 to 100,000, more preferably 2,000 to 500,000 can be used. By the addition of the stabilizer, the catalytic activity of the hydrogenation catalyst is enhanced, the amount of the catalyst used can be reduced, and the storage stability of the catalyst solution can be improved.

Hydrogenation catalyst stabilizers are soluble or dispersible in a catalyst-containing solution and a polymer or polymer latex (meaning that they are in a stable dispersed state like a colloid), and aggregate in the latex. Any material can be used as long as it can maintain the hydrogenation catalyst in a dissolved or dispersed state without causing precipitation or precipitation. Specific examples of the hydrogenation catalyst stabilizer include polymers of vinyl compounds having a polar group in a side chain such as polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl acetal, and polyalkyl vinyl ether; sodium polyacrylic acid; Metal salts of polyacrylic acid such as polyacrylic acid potassium; polyethers such as polyethylene oxide, polypropylene oxide, and ethylene oxide-propylene oxide copolymer; cellulose derivatives such as carboxymethyl cellulose and hydroxypropyl cellulose; Natural polymers such as gelatin and albumin; Among them, a polymer or polyether of a vinyl compound having a polar group in a side chain is preferable. Polyvinyl pyrrolidone and polyalkyl vinyl ethers are particularly preferred. The hydrogenation catalyst stabilizer can be dissolved or dispersed in the latex together with the hydrogenation catalyst and used for the hydrogenation reaction. In this case, the concentration of the hydrogenation catalyst stabilizer in the latex is preferably 0.5 to 20 times, more preferably 1 to 10 times, the weight of the metal element in the hydrogenation catalyst.

 The hydrogenation catalyst stabilizer can be dissolved or dispersed in water or an organic solvent together with the hydrogenation catalyst, prepared in advance as a hydrogenation catalyst solution, and supplied to the hydrogenation reaction. When the catalyst solution is an aqueous solution, for example, an inorganic acid such as nitric acid, sulfuric acid, hydrochloric acid, bromic acid, perchloric acid, or phosphoric acid; a metal salt such as a sodium salt or a potassium salt of such an inorganic acid; Acid, etc., which may increase the solubility of the hydrogenation catalyst in water. In this case, the concentration of the acid in the catalyst aqueous solution is preferably 1 to 20 times, more preferably 1 to 10 times the molar amount of the metal element in the hydrogenation catalyst.

 In particular, the method for preparing the catalyst aqueous solution preferably includes the step of preparing an acidic aqueous solution of the hydrogenation catalyst, followed by the step of adding the hydrogenation catalyst stabilizer of the present invention to the aqueous solution.

 The catalyst aqueous solution does not cause aggregation or precipitation of the hydrogenation catalyst even after standing at 25 ° C for 1 hour or more, preferably 1 day or more, more preferably 14 days or more. The temperature of the hydrogenation reaction is usually 0 ° (3 to 200 ° C., preferably 5 ° C. to 150 ° C., more preferably 10 ° to 100 ° C.). This is not desirable because side reactions such as hydrogenation of the nitrile group may occur, and if the reaction temperature is excessively low, the reaction rate is reduced and is not practical.

The pressure of hydrogen is usually from atmospheric pressure to 2 OMPa, preferably from atmospheric pressure to 15 MPa, more preferably from atmospheric pressure to 1 OMPa. The reaction time is not particularly limited, but is usually 30 minutes to 50 hours. Note that it is preferable to first pressurize the hydrogen gas after the reaction system is replaced with an inert gas such as nitrogen, and then replaced with hydrogen. The hydrogenation reaction of the latex system and the solution system in step (A) can be performed under basic conditions to improve the reaction efficiency and reduce the amount of the hydrogenation catalyst used. The method of performing the reaction under basic conditions is not particularly limited, and can be appropriately selected depending on the reaction system of the latex-based hydrogenation and the solution-based hydrogenation. For example, in the case of latex-based hydrogenation, a method in which a basic compound is directly added to the reaction system to increase the pH of the hydrogenation reaction solution (latex) measured with a pH meter to more than 7 is mentioned. Can be The pH of the hydrogenation reaction solution is preferably in the range of 7.2 to 13, more preferably 7.5 to 12.5, and even more preferably 8.0 to 12. The method and timing for adding the basic compound are not particularly limited. For example, a method in which a basic compound is added to latex before adding a catalyst to the hydrogenation reaction solution; A method of adding a compound;

 In the solution-based hydrogenation, as described above, the step of preparing the conjugated gen-based polymer rubber (raw material) to be subjected to the hydrogenation reaction is performed by bringing the polymer into contact with a basic aqueous solution. A method of adding a basic compound to the reaction system after the start of the hydrogenation reaction;

 Further, in both latex-based hydrogenation and solution-based hydrogenation, a method in which a basic compound is added at the stage of preparing a catalyst solution of an unsupported catalyst, particularly a catalyst aqueous solution, can be adopted. When an inorganic acid or the like is used to promote the dissolution of the unsupported catalyst in water, an amount of a basic compound that neutralizes the inorganic acid is added to the aqueous catalyst solution.

 The basic compound for making the hydrogenation reaction solution or the catalyst solution basic is not particularly limited, and examples thereof include an alkali metal compound, an alkaline earth metal compound, ammonia, an ammonium salt compound, and an organic amine compound. . Preferably, they are an alkali metal compound and an alkaline earth metal compound.

Examples of the alkali metal compound include hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; carbonate compounds such as lithium carbonate, sodium carbonate, and potassium carbonate; lithium hydrogen carbonate, sodium hydrogen carbonate, and hydrogen carbonate power. Bicarbonate compounds such as lithium; oxides such as lithium oxide, potassium oxide, and sodium oxide; organic acid salt compounds such as acetic acid potassium and sodium acetate; lithium methoxide, lithium ethoxide, sodium methoxide, sodium chloride Alkoxides such as sodium hydroxide and potassium pentoxide; phenoxides such as sodium phenoxide and potassium phenoxide; and the like. Preferred are alkali metal hydroxides, carbonate compounds and bicarbonate compounds, more preferably Hydroxide.

 Examples of the alkaline earth metal compound include hydroxides, carbonate compounds, hydrogen carbonate compounds, oxides, organic acid salt compounds, alkoxides of alkaline earth metals such as magnesium, calcium, strontium, and barium. Phenoxides and the like. Preferred are hydroxides, carbonate compounds and hydrogen carbonate compounds of alkaline earth metals, more preferably hydroxides.

 Examples of the ammonium salt compound include ammonium carbonate and ammonium hydrogen carbonate. Examples of the organic amine compound include aliphatic, alicyclic, and aromatic mono- and polyamino compounds, such as triethylamine, ethanolamine, molwood phosphorus, N-methylmolwood phosphorus, pyridine, hexamethylene diamine, and dodecamethylene. Examples thereof include diamine and xylylenediamine.

 These basic compounds can be used as they are, or can be used after being diluted or dissolved with water or an organic solvent such as alcohol or ketone. The basic compounds may be used alone or in combination of two or more, and the amount used may be appropriately selected so that the hydrogenation reaction solution or the catalyst solution exhibits basicity.

 Hydrogenation rate of hydrogenated conjugated gen-based polymer obtained by the production method of the present invention (Ratio of hydrogenated carbon-carbon double bond to total carbon-carbon double bond existing in polymer before reaction) ) Can be arbitrarily controlled within the range of 1 to 100%. The hydrogenation rate represented by iodine value is preferably not more than 20.

 One of the major features of the production method according to the present invention is that, as a post-treatment method of the above-mentioned hydrogenation reaction step (A), an oxidation treatment step of bringing a catalyst (catalyst residue) contained in a reaction mixture into contact with an oxidizing agent. (B). After completion of the hydrogenation reaction, the catalyst in the system is in a reduced state, and in step (B), it is oxidized by bringing it into contact with an oxidizing agent. The oxidizing agent is not particularly limited as long as it has catalytic oxidizing ability, and can be appropriately selected according to each of the reaction systems of the latex hydrogenation and the solution hydrogenation.

Examples of the oxidizing agent for the latex-based hydrogenation include air (oxygen); peroxides such as hydrogen peroxide, peracetic acid, and perbenzoic acid; and the like, preferably air, hydrogen peroxide, and more preferably peroxide. Hydrogen oxide. As the oxidizing agent for solution hydrogenation, Iodine; metal octogenates such as ferric chloride (F e CI ₃ ); peroxides such as hydrogen peroxide, peracetic acid, and perbenzoic acid; and the like, preferably ferric chloride, iodine, and the like. Preferably, it is ferric chloride.

 The use amount of these catalyst oxidizing agents is not particularly limited, and is 1 to 100 times, preferably 3 to 50 times the mol of the platinum group element contained in the catalyst used for the hydrogenation reaction. The contact temperature is usually 0 to 100, preferably 50 to 95 ° C, more preferably

70 to 90 ° C. The contact time is usually 0 minutes to 20 hours, preferably 30 minutes to

10 hours.

 The method of contacting the catalyst with the oxidizing agent is not uniform depending on the type of the oxidizing agent, but can be appropriately selected depending on the reaction system of the latex-based hydrogenation and the solution-based hydrogenation. For example, when air is used as the oxidizing agent in the latex-based hydrogenation step (B), air is continuously blown into the open reaction mixture; the gaseous atmosphere of the open or closed reaction mixture container is changed. Stirring the reaction mixture with air; and the like. When using hydrogen peroxide, it may be added to the reaction mixture and stirred. When an oxidizing agent such as ferric chloride, iodine, or hydrogen peroxide is applied to the solution-based hydrogenation step (B), a predetermined amount thereof may be added to the reaction mixture and stirred.

 Another major feature of the production method according to the present invention is that a complexing treatment is carried out following the above-mentioned step (B), or simultaneously or during the same. That is, a complexing step (C) in which a complexing agent is added to the reaction mixture oxidized in step (B) to form a catalyst complex is essential.

 The complexing agent used in the step (C) is not particularly limited as long as it has a catalytic complexing ability, and can be appropriately selected depending on the reaction system of the latex-based hydrogenation and the solution-based hydrogenation. The complexing method is also not particularly limited, and the complexing treatment can be carried out by adding a predetermined amount of a complexing agent as it is or as a solution of water or an organic solvent to the reaction mixture, followed by stirring.

As a complexing agent for latex-based hydrogenation, one that forms a water-insoluble complex with a platinum group element is preferable. As such a complexing agent, for example, a talented xime compound is cited, and from the strength of complex formation ability, a talented ximexium compound is preferable, and dimethyl dalioxime, Α, J3-alkanedione dicumium, such as cyclohexanediene dimedium, is more preferred. Of these, dimethyl dalioxime is most preferred.

 Examples of the complexing agent for solution-based hydrogenation include ammonia; ammonium salts of organic acids or inorganic acids such as ammonium acetate, ammonium benzoate, and ammonium sulfate; and the like. Preferred are ammonia and ammonium acetate, and more preferred is ammonia.

 The amount of the complexing agent to be used is generally 1- to 50-fold, preferably 2- to 30-fold the molar amount of the platinum group element contained in the catalyst used in the hydrogenation reaction in step (I). The complexing treatment time is generally about 0 minutes to 20 hours, preferably 30 minutes to 10 hours.

 The complexing temperature is usually from 0 to 100 ° C. For example, in the complexing treatment of latex-based hydrogenation, the complex is grown or aggregated to a particle size larger than the polymer particles. It is preferable to take the steps of stirring under heating, followed by standing, and cooling. The latex PH at the time of complex formation is preferably adjusted to about 8 to 10.5.

 In the production method of the present invention, a catalyst separation step (D) is provided following the above-described complexation step (C). That is, it is essential to separate the formed complex from the complexed reaction mixture. The method of separating the formed complex is not particularly limited, and an appropriate method of separating the complex can be adopted according to each of the reaction systems of latex hydrogenation and solution hydrogenation.

 For example, in the latex-based hydrogenation, when dimethylglyoxime is used as a complexing agent in the step (C), an insoluble complex is expected to be present in the reaction mixture (latex). By the operation, the precipitate can be easily removed and recovered from the reaction mixture. When filtering the precipitate, there is no particular limitation on a filtration device, a filtration method, and the like, except that a filter cloth or a filter paper that transmits only latex is used. Either vacuum filtration or pressure filtration can be employed, but in order to perform filtration efficiently, it is preferable to coat the filter cloth with a filter aid such as diatomaceous earth and perform vacuum filtration.

When separating the formed complex, for example, a method in which an adsorbent is contained in a reaction mixture containing the complex, and the reaction mixture is stirred or allowed to stand to adsorb the complex can be employed. The use of an adsorbent is particularly suitable in solution-based hydrogenation. The adsorbent may be present in the reaction mixture from the beginning, but is preferably added to the reaction mixture containing the complex after the completion of the complexing step (C). Examples of the adsorbent include activated carbon; silicon-containing inorganic compounds such as diatomaceous earth, talc, clay, activated clay, and silica; activated alumina; synthetic zeolite such as radiolite; ion exchange resin; However, among these, activated carbon and silicon-containing inorganic compounds are preferred.

 The adsorption treatment can be performed by a method of stirring and mixing the reaction mixture, a method of passing the reaction mixture through a column filled with these adsorbents, and the like. The adsorbent that has adsorbed the complex can be removed from the reaction mixture by a known separation operation such as filtration or eccentric separation.

 As described above, by allowing the adsorbent to coexist in the hydrogenation reaction mixture, preferably by adding the adsorbent to the hydrogenation reaction mixture after the complexation treatment, When the formed complex is adsorbed on the adsorbent and separated, the oxidation reaction step (B) of bringing the catalyst contained in the hydrogenation reaction mixture into contact with the oxidizing agent may be omitted, even if the hydrogenation reaction mixture is omitted. The contained platinum element-containing catalyst can be efficiently removed. That is, the method including the following steps (A), (C), (C '), and (D) enables efficient production of a hydrogenated conjugated gen-based polymer. Reaction step (A) for hydrogenating a conjugated polymer in the presence of a catalyst containing a platinum group element; complexing step (C) for adding a complexing agent to the reaction mixture to form a complex of an oxidized catalyst By allowing the adsorbent to coexist in the hydrogenation reaction mixture, preferably by adding the adsorbent to the hydrogenation reaction mixture after the complexation treatment, to reduce the complex formed by the complexation treatment. A method for producing a hydrogenated conjugated gen-based polymer, comprising: a step of adsorbing on the adsorbent (C ′); a step of recovering the adsorbed complex from the reaction mixture (D).

 In the production method of the present invention, the steps (B) to (D) as described above are employed to separate and recover the hydrogenation catalyst containing the platinum group element applied to the step (A) very efficiently. be able to.

As a filtration device used for separation by filtration, a filtration device having a structure in which a plurality of filter elements are housed in a sealable housing is preferably used. You. Here, “filtration element J” includes a filter medium alone or a combination of a filter medium and a filter plate, and refers to an entire member having a “filtration” function of a filtration device. In particular, in view of the filtration area and the filtration speed, the filter element is preferably a cylindrical or hollow disk, and the number is preferably 5 or more, more preferably 10 or more. As a filtering device equipped with such a filter element, there is a pressurized filter which is called a fundabag filter or a leaf filter.

 For efficient filtration without clogging, the filter element can be pre-coated with a filter aid such as diatomaceous earth. Specifically, before supplying the substance to be filtered, a suspension of the filter aid is filled in the housing, and the suspension is filtered, so that the filter aid is collected on the filter element. A layer is formed.

 In the latex-based hydrogenation, a hydrogenated conjugated polymer latex from which the hydrogenation catalyst has been almost completely removed is obtained, so that it can be directly used as a latex product. The content of the platinum group element in the latex (per polymer) is usually at most 300 ppm, preferably at most 100 ppm. Further, by coagulating and drying the polymer latex by a known method, a hydrogenated conjugated polymer rubber from which the hydrogenation catalyst has been almost removed can be obtained. That is, a method generally used in industry, for example, adding a coagulant such as aluminum sulfate, magnesium sulfate, calcium chloride to a polymer latex to obtain crumbs, washing with water as needed, draining, hot air Through a drying step such as drying, drying under reduced pressure, or extrusion drying, the hydrogenated co-polymer polymer can be obtained. .

 The separated platinum group element-containing catalyst and its complex can be recovered and reused by dissolving, decomposing, reacting, etc.

When a supported catalyst is used in the solution-based hydrogenation step (A), by performing steps (B) to (D), a considerable amount of the catalyst component dropped from the support into the reaction solvent is separated. Can be recovered. Also, when an unsupported catalyst is used in the solution-based hydrogenation step (A), a considerable amount of the used catalyst can be separated and recovered from the reaction mixture. In liquid hydrogenation, after separating the catalyst in step (D), the organic solvent is distilled off by a known method to obtain a hydrogenated conjugated gen-based polymer. Can be.

 When an unsupported catalyst is used in latex or solution hydrogenation, the recovery of platinum group elements can be generally 70% or more, and if conditions are selected, 95% or more can be achieved. In addition, when a supported catalyst is used, the total recovery of the platinum group element combined with the platinum group element recovered in the state of being supported on the carrier is usually 70% or more, and if the conditions are selected, it is 95% or more. can do.

 The latex of hydrogenated conjugated polymer finally recovered by the latex-based hydrogenation method usually has a platinum group element content of 100 ppm or less, preferably 80 ppm or less, per polymer. Preferably, it can be 50 ppm or less. Further, the hydrogenated conjugated polymer rubber obtained by separating from the above latex and the hydrogenated conjugated polymer rubber obtained in the solution hydrogenation also contain the content of the platinum group element derived from the hydrogenation catalyst. However, it can be obtained as extremely low as described above. The content of the platinum group element is preferably as low as possible, and the lower limit is not limited. Generally, a hydrogenated conjugated polymer rubber having a content per polymer rubber of about 5 ppm or less is industrially advantageous. It is difficult to manufacture.

 Also, the separated platinum group element-containing catalyst and its complex can be recovered by dissolution, decomposition, reaction treatment, etc., and reused.

 Example

 Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Parts and percentages in these examples are by weight unless otherwise specified.

 The hydrogenation rate of the hydrogenated conjugated diene polymer was measured by proton NMR. After the recovery of the hydrogenation catalyst, the amount of palladium in the separated hydrogenated conjugated polymer rubber was determined by dissolving in sulfuric acid after carbonizing / ashing a part of the hydrogenated polymer rubber at 600 ° C. And measured by atomic absorption spectrometry.

 Example 1 Latex-based hydrogenation

The autoclave was charged sequentially with 2 parts of potassium oleate, about 80 parts of ion-exchanged water, 37 parts of acrylonitrile, and 0.5 parts of t-dodecylmercaptan. After replacing the inside of the reactor with nitrogen, 63 parts of butadiene were sealed. Cool reactor to Ί 0 ° C Then, 0.1 part of peroxide at the mouth of cumene hydride and 0.0 part of ferrous sulfate were added. Next, the contents were stirred for about 6 hours while maintaining the reactor at 10 ° C. Thereafter, a 10% aqueous solution of hydroquinone was added to the reactor to terminate the polymerization. Unreacted monomers were removed from the polymerization reaction solution to obtain a latex. The polymerization conversion was 90%. The acrylonitrile-butadiene copolymer (NBR) latex thus obtained was subjected to a hydrogenation reaction in a latex state.

 Palladium acetate (the amount of Pd metal used was 700 ppm based on the NBR ratio) was added to water, and nitric acid was added at a molar equivalent of 5 times the amount of palladium to prepare 300 parts of a palladium acidic aqueous solution. . To the aqueous solution, polyvinyl virolidone having a weight average molecular weight of 50,000 was added 5 times by weight with respect to palladium. Further, an aqueous potassium hydroxide solution was added to prepare an aqueous catalyst solution A having a pH of 9.0.

 The total amount of the above-mentioned NBR latex (solid content: 120 parts) and the aqueous solution of catalyst A adjusted to a total solid content concentration of 30% and the catalyst aqueous solution A were put into a tote clave equipped with a stirrer, and nitrogen gas was allowed to flow for 10 minutes. The dissolved oxygen in the latex was removed. After purging the system twice with hydrogen gas, 3 MPa of hydrogen was pressurized. The contents were heated to 50 ° C and stirred for 6 hours to carry out a hydrogenation reaction to obtain a hydrogenated NBR reaction mixture in a latex state.

 To the reaction mixture in the latex state, 2 parts of a 30% aqueous hydrogen peroxide solution was added, and the mixture was stirred (oxidation treatment) at 80 ° C for 2 hours. Next, the pH of the reaction mixture was adjusted to 9.5, and dimethyldalioxime corresponding to 5 times the molar amount of palladium contained in the catalyst aqueous solution A was added as a powder. When the reaction mixture was stirred at 80 ° C for 5 hours (complexation treatment), insolubles were precipitated in the latex. The whole latex was subjected to suction filtration to separate a precipitate. The obtained white filtrate was concentrated under reduced pressure on a low evaporator to obtain a solid hydrogenated NBR. Hydrogenation The hydrogenation rate of NBR was 93%. The amount of palladium in the hydrogenated NBR was 37 ppm. This amount of palladium corresponded to 5.2% of the palladium charged to the hydrogenation reaction, and the remaining palladium had been removed from the hydrogenated NBR.

 Comparative experiment

In addition, the storage stability of the same aqueous catalyst solution A as used in the hydrogenation in Example 1 to which the hydrogenation catalyst stabilizer (polyvinyl pyrrolidone) was added was separately evaluated. As a result, no aggregation or precipitation was observed at all even when left at 25 ° C for about 4 days.

 Furthermore, in order to examine the effect of the hydrogenation catalyst stabilizer (polyvinylpyrrolidone) added prior to the hydrogenation in the method of Example 1 described above, a comparative experiment was performed as follows.

 The hydrogenation reaction and the recovery of the hydrogenated polymer were performed in the same manner as in Example 1 except that polyvinylpyrrolidone was not added to the hydrogenation catalyst aqueous solution A used in the method of Example 1 above. . Hydrogenation The hydrogenation rate of NBR reached only 70%. As a result of evaluating the storage stability of the catalyst aqueous solution A to which polyvinylpyrrolidone was not added, a slight precipitate was observed when the catalyst aqueous solution A was left at 25 ° C for 1 hour.

 As is clear from the above Example 1 and the comparative experiment, when the catalyst stabilizing agent was not co-present during the hydrogenation reaction, the hydrogenation addition rate of the hydrogenated conjugated polymer was 90%. , And the catalyst precipitated or precipitated when the aqueous catalyst solution was stored for a long period of time. On the other hand, when the hydrogenation reaction was performed in the presence of a catalyst stabilizer, the hydrogenation rate of the hydrogenated conjugated polymer reached 90% or more, and the aqueous solution of the catalyst was stored for a long time. However, it was still uniformly dissolved.

 Comparative Example 1 Latex-based hydrogenation

 In the same manner as in Example 1, preparation of NBR (polymerization conversion: 90%), preparation of catalyst aqueous solution A, hydrogenation reaction in latex state, and (hydrogenation of 92%) were sequentially performed. The pH of the reaction mixture was adjusted to 9.5 without adding the hydrogen peroxide solution and dimethyl dalioxime used in Example 1, and the mixture was stirred at 80 ° C for 7 hours. There was no change in the state of the reaction mixture (latex), and no precipitate as in Example I was observed. When the whole amount of the latex was subjected to suction filtration, all of the latex passed through the filter paper. The filtrate was once darker and dark gray. The obtained filtrate was concentrated under reduced pressure by a rotary evaporator to obtain solid hydrogenated NBR.

 The amount of palladium in the hydrogenated NBR was 6990 ppm, which was equivalent to 98.6% of the palladium charged in the hydrogenation reaction.

 Example 2 Solution hydrogenation

Acrylonitrile-butadiene copolymer (NBR) Tex was prepared. The above latex was dropped into coagulated water while stirring 300 parts of coagulated water in which 3 parts of calcium chloride (coagulant) was dissolved, to coagulate the latex. The crumb was separated from the coagulated water, washed with water, and dried under reduced pressure at 50 ° C. This crumb was dissolved in acetone to prepare a 15% polymer solution. 800 parts of the acetone solution

Palladium acetate (the amount used is 500 ppm in the ratio of Pd metal / NBR described above) was added to (solid content: 120 parts), and the mixture was charged into a Saito clave equipped with a stirrer. Nitrogen gas was allowed to flow for 0 minutes. To remove dissolved oxygen. After purging the system twice with hydrogen gas, 5 MPa of hydrogen was pressurized. The contents were heated to 50 ° C and stirred for 6 hours to carry out a hydrogenation reaction.

 After the completion of the hydrogenation reaction, the system was cooled to room temperature and the hydrogen in the system was replaced with nitrogen. 1.84 parts of ferric chloride was added to the reaction mixture, and the mixture was stirred at 30 ° C for 3 hours (oxidation treatment). Next, 16 parts of ammonia water was added and the mixture was stirred at 80 ° C for 5 hours (complexation treatment). After cooling, 6 parts of activated carbon was added, and the mixture was stirred at room temperature for 3 hours (adsorption treatment), and then the activated carbon was filtered off. The obtained filtrate was added to 10 times the amount of water, and the precipitated rubber was taken out. It was dried with a vacuum drier for 24 hours to obtain hydrogenated NBR.

 The amount of palladium in this hydrogenated NBR was 50 ppm, corresponding to 10% of the palladium charged in the hydrogenation reaction, and the remaining palladium had been removed from the hydrogenated NBR.

 Comparative Example 2 Solution hydrogenation

 In the same manner as in Example 2, preparation of NBR (polymerization conversion: 90%), preparation of an acetone solution thereof, and hydrogenation reaction were sequentially performed. The reaction mixture was stirred at 30 ° C. for 3 hours without adding the ferric chloride used in Example 2. Next, 16 parts of water was added without adding the ammonia water used in Example 2, and the mixture was stirred at 80 ° C. for 5 hours. After cooling, 6 parts of activated carbon was added, and the mixture was stirred at room temperature for 3 hours (adsorption treatment), and then the activated carbon was filtered off. The resulting filtrate was added to 10 times the amount of water, and the precipitated rubber was taken out. It was dried in a vacuum dryer for 24 hours to obtain hydrogenated NBR.

 The amount of palladium in the hydrogenated NBR was 495 ppm, which corresponded to 99% of the palladium charged in the hydrogenation reaction.

As is clear from the comparison between Example 1 and Example 2 and Comparative Example I and Comparative Example 2, the presence or absence of oxidation treatment and complexation treatment as a post-treatment method after the completion of the hydrogenation reaction was determined. Thus, it can be seen that the palladium content in the obtained hydrogenated NBR is significantly different. It was confirmed that the catalyst used in the hydrogenation reaction (latex-based, solution-based) can be efficiently separated from the reaction mixture by the oxidation and complexation treatments.

 Example 3

 In a Saito clave, 2 parts of potassium oleate, 180 parts of ion-exchanged water, 37 parts of acrylonitrile, and 0.5 part of t-decyl mercaptan were sequentially charged. After replacing the inside of the reactor with nitrogen, 63 parts of butadiene were sealed. The reactor was cooled to 10 ° C. and 0.01 part of peroxide at the mouth of cumenehydride and 0.01 part of ferrous sulfate were added. The contents were then stirred for 16 hours while maintaining the reactor at 10 ° C. Thereafter, a 0% aqueous solution of octa-idoquinone was added into the reactor to terminate the polymerization. Unreacted monomers were removed from the polymerization reaction solution to obtain an acrylonitrile-butadiene copolymer (NBR) latex. The polymerization conversion was 90%. While stirring 300 parts of coagulated water in which 3 parts of calcium chloride (coagulant) was dissolved at 50 ° C., the latex was dropped into the coagulated water. An aqueous solution of potassium hydroxide was added thereto to precipitate polymer crumb while maintaining the pH at 11.5. An NBR column was fractionated from the coagulated water, washed with water, and dried at 50 ° C under reduced pressure. This crumb was dissolved in acetone to prepare a 15% polymer solution. To 800 parts of the acetone solution (120 parts of solid content) was added palladium acetate (the amount of Pd metal used was 500 ppm with respect to the NBR), and the mixture was charged into an autoclave equipped with a stirrer. Dissolved oxygen was removed by flowing nitrogen gas for 10 minutes. After purging the system twice with hydrogen gas, 5 MPa of hydrogen was pressurized. The contents were heated to 50 ° C and stirred for 6 hours to carry out a hydrogenation reaction.

 After the hydrogenation reaction, cool to room temperature and replace the hydrogen in the system with nitrogen. Then add 1.84 parts of ferric chloride to the reaction solution and stir at 30 ° C for 3 hours (oxidation treatment) Then, 16 parts of aqueous ammonia was added, followed by stirring at 80 ° C for 5 hours (complexation treatment). After cooling, 6 parts of activated carbon was added, and the mixture was stirred at room temperature for 3 hours (adsorption treatment), and then the activated carbon was filtered off. The obtained filtrate was poured into 10 times the amount of water, and the precipitated rubber was collected. It was dried in a vacuum dryer for 24 hours to obtain hydrogenated NBR.

The amount of palladium in the hydrogenated NBR was 50 ppm, and the recovery of palladium used in the hydrogenation reaction was 90%. Comparative Example 3

 Hydrogenated NBR was obtained in the same manner as in Example 3. However, after the completion of the hydrogenation reaction, the complexing treatment with ammonia and the adsorption treatment with activated carbon were performed without performing the oxidation treatment with ferric chloride.

 The amount of palladium in the obtained hydrogenated NBR was 200 ppm, and the recovery of palladium used in the hydrogenation reaction was 60%.

 Comparative Example 4

 In Example 3, 16 parts of water was added without addition of ammonia water (complexation treatment) after the hydrogenation reaction, followed by stirring at 80 ° C for 5 hours. After cooling, 6 parts of activated carbon was added, and the mixture was stirred at room temperature for 3 hours (adsorption treatment), and then the activated carbon was filtered off. The resulting filtrate was added to 10 times the amount of water, and the precipitated rubber was taken out. It was dried with a vacuum dryer for 24 hours to obtain hydrogenated NBR.

 The amount of palladium in this hydrogenated NBR was 495 ppm, and the recovery of palladium used in the hydrogenation reaction was only 1%.

 Example 4

 Example 3 was repeated except that palladium chloride-silica-supported catalyst (Pd was used in an amount of 200 ppm based on the ratio of Nd to Pd metal) was used in place of palladium acetate as the hydrogenation catalyst. After the adsorption treatment, the supported hydrogenation catalyst and the activated carbon were separated by filtration.

 The amount of palladium in the hydrogenated NBR was 60 ppm, and the recovery of palladium used in the hydrogenation reaction was 70%.

 Comparative Example 5

 In Example 4, 16 parts of water was added without adding aqueous ammonia after the hydrogenation reaction, followed by stirring at 80 for 5 hours. After cooling, 6 parts of activated carbon was added, and the mixture was stirred (adsorption treatment) at room temperature for 3 hours. Then, the supported hydrogenation catalyst and activated carbon were separated by filtration. The obtained filtrate was added to 10 times the amount of water, and the precipitated rubber was taken out. It was dried in a vacuum dryer for 24 hours to obtain hydrogenated NBR.

The amount of palladium in the hydrogenated NBR was 140 ppm, and the recovery of palladium used in the hydrogenation reaction was 30%. As is clear from the comparison between Example 3 and Example 4 and Comparative Examples 3 to 5, in producing hydrogenated NBR using an unsupported platinum group hydrogenation catalyst, the reaction after the hydrogenation reaction was performed. By subjecting the mixture to oxidation treatment, complexing treatment and adsorption removal, hydrogenated NBR with extremely low platinum group element content was obtained (comparison between Example 3 and Comparative Example 3). Omitting the complexation increased the metal content in the hydrogenated NBR (Comparative Example 4).

 Also, when hydrogenating NBR is produced using a supported platinum group hydrogenation catalyst, the reaction mixture after the hydrogenation reaction is oxidized, complexed, and adsorbed to remove the platinum group element. Hydrogenated NBR with low content was obtained (Example 4). On the other hand, if the complexing treatment was not performed, the metal content in the hydrogenated NBR increased (Comparative Example 5). As a result, when the supported hydrogenation catalyst was used, desorption of the catalyst from the support occurred, and it was shown that the method of the present invention is also effective in overcoming this.

 Example 5

 Hydrogenation was performed in the same manner as in Example 1 to obtain a hydrogenated NBR reaction mixture in a latex state. However, the amount of palladium acetate used as a hydrogenation catalyst was changed from 700 ppm to 800 ppm in Pd metal ZNBR ratio.

 To the resulting hydrogenated NBR reaction mixture, 24 L of 30% hydrogen peroxide solution was added, and the mixture was stirred (oxidation treatment) at 80 ° C for 2 hours. —Next, the pH of the reaction mixture (latex) was adjusted to 9.5, and dimethylglyoxime corresponding to 5 times the molar amount of palladium contained in the catalyst aqueous solution A was added as a powder. Then, when the mixture was heated to 80 ° C and stirred for 5 hours, insolubles were precipitated in the latex.

 The reaction mixture containing the above insolubles was filtered using a FUNDABAC filter (trade name: FUNDABAC, manufactured by Ishikawajima-Harima Heavy Industries, Ltd.). The fundaback filter has a large number of cylindrical filter elements (Ί6 to 28 depending on the model) in a sealable housing. Each filter element has a tubular filter plate covered with a filter cloth. The tubular filter plate consists of a candle piece through which the filtrate flows and a riser pipe in the center where the filtrate collects.

The filter element was precoated with radiolite (diatomaceous earth) suspension and filtered under pressure. The obtained white filtrate was concentrated under reduced pressure by a rotary evaporator to obtain a solid hydrogenated NBR. Hydrogenation The hydrogenation rate of NBR was 93%.

 The amount of palladium in the hydrogenated NBR was 40 ppm. The amount of palladium lost due to leakage during filtration and adhesion to the housing wall was only 1% of the amount used for the hydrogenation reaction.

 Example 6

 The operation was performed in the same manner as in Example 5, except that the filtration was performed using Leaffill Yu (Ishikawajima-Harima Heavy Industries, Ltd.) as a filtration device. The leaf filter has one or two disc-shaped filter elements, which are attached to a cylindrical core passing through the center. One end of the cylindrical core is closed, and the other end is opened to the outside through the housing wall. At least one core hole is provided in each of the filter element mounting portions, and the filter is filtered by the filter element. The structure allows liquid to be collected and taken out. Each filter element is made of stainless steel wire mesh. Precoating with a radio light was performed in the same manner as in Example 5. The time required to obtain the same amount of filtrate as in Example 5 was the same as in Example 5.

 The amount of palladium in the obtained hydrogenated NBR was 40 ppm. The amount of palladium lost due to leakage during filtration and adhesion to the housing wall was 3% of the amount used for the hydrogenation reaction.

 Ratio experiment

 In order to investigate the effect of the filtration device having a plurality of filter elements used in Example 5 and Example 6, the following comparative experiment was performed using a filtration device having a single filter element.

 That is, the same operation as in Example 5 was performed except that the filtration was performed using a membrane filter (manufactured by Millipore) having only 1 mm of a filter element covered with a polytetrafluoroethylene membrane as a filtration device. Pre-recording by radio was not performed.

The amount of palladium in the obtained hydrogenated NBR was 40 ppm, but clogging occurred during filtration, so the filter element was replaced once. In addition, Example 5 and The time required to obtain the same amount of filtrate was twice that of Example 5. As a result, the loss of palladium was 15% of the amount used in the hydrogenation reaction.

 As is clear from Examples 5 and 6 and the comparative experiment, when filtration is performed using a membrane filter having only one filter element, the filtration speed decreases, clogging occurs, and catalyst loss occurs. Is also big. On the other hand, it was confirmed that if filtration was performed using a filtration device having a plurality of filter elements, the used catalyst could be efficiently separated without loss, and a polymer with a small residual amount of palladium was obtained.

 Example 7

 In the same manner as in Example 1, an acrylonitrile-butadiene copolymer (NBR) latex was prepared. While stirring 300 parts of coagulated water in which 3 parts of calcium chloride (coagulant) was dissolved at 50 ° C., the above latex was dropped into coagulated water to coagulate the latex. The crumb was separated from the coagulated water, washed with water, and dried under reduced pressure at 50 ° C. This crumb was dissolved in acetone to prepare a 15% polymer solution.

 In the same manner as in Example 1, palladium acetate (the amount of use was 700 ppm in the ratio of Pd metal / NBR) was added to water, and nitric acid was added at a molar equivalent of 5 times the amount of palladium to give 300 parts. Was prepared. To the aqueous solution, polymethyl vinyl ether having a weight average molecular weight of 3,000 was added 5 times by weight with respect to palladium. Further, an aqueous solution of a water-soluble hydroxide was added to prepare a catalyst aqueous solution B having a pH of 9.0. To 800 parts of the above acetone solution of the polymer (120 parts of solid content) was added the above aqueous solution of palladium acetate B (the amount used was 500 ppm in the ratio of Pd metal / NBR), and a stirrer was added. The solution was charged into a single clave, and nitrogen gas was flowed for 10 minutes to remove dissolved oxygen. After the inside of the system was replaced twice with hydrogen gas, 5 MPa of hydrogen was pressurized. The contents were heated to 50 ° C and stirred for 6 hours to carry out a hydrogenation reaction.

After the completion of the hydrogenation reaction, the system was cooled to room temperature and the hydrogen in the system was replaced with nitrogen. 1.84 parts of ferric chloride was added to the reaction mixture, and the mixture was stirred at 30 ° C for 3 hours (oxidation treatment). Next, 6 parts of ammonia water was added and the mixture was stirred at 80 ° C for 5 hours (complexation treatment). After cooling, 6 parts of activated carbon was added, and the mixture was stirred at room temperature for 3 hours (adsorption treatment), and then the activated carbon was filtered off. The obtained filtrate was added to 10 times the amount of water, and the precipitated rubber was taken out. Vacuum dryer it For 24 hours to obtain hydrogenated NBR. Hydrogenation The hydrogenation rate of NBR was 95%. In addition, as a result of evaluating the storage stability of the aqueous catalyst solution B used for hydrogenation, no aggregation or precipitation was observed at all even after standing at 25 ° C for 14 days.

 The amount of palladium in the hydrogenated NBR was 50 ppm.

 Comparative experiment

 In order to investigate the effect of the hydrogenation catalyst stabilizer (polymethyl vinyl ether), the hydrogenation reaction and the hydrogenation of the hydrogenated polymer were carried out in the same manner as in Example 7, except that polymethyl vinyl ether was not added to the hydrogenation catalyst solution B. Recovery operation was performed. The hydrogenation rate of the hydrogenated NBR reached only 85%. The storage stability of the aqueous catalyst solution A used for hydrogenation was evaluated. As a result, the catalyst was completely precipitated and precipitated when left at 25 C for 1 hour.

 As can be seen from Example 7, when the hydrogenation reaction was carried out in the presence of a catalyst stabilizer during the hydrogenation reaction, the hydrogenation addition rate of the hydrogenated conjugated gen-based polymer reached 90% or more, Even when the aqueous solution is stored for a long time, it is still uniformly dissolved. Industrial applicability

 According to the catalyst recovery method of the present invention, the platinum group element-containing catalyst used in the hydrogenation reaction can be easily recovered and reused. Compounds, especially hydrogenated conjugated gen-based polymers, can be industrially advantageously produced.

 The latex of the hydrogenated conjugated gen-based polymer obtained by the production method of the present invention is useful as an adhesive, a coating agent, a paint, a raw material for dip-formed gloves, and the like. Since the amount of residual platinum group elements in latex is significantly reduced, when used as an adhesive, coating agent, paint, etc., the corrosion resistance of the adhered or coated metal material is high, and the residual platinum group elements Since there is no darkening caused by paint, coating agents, paints, etc. have a high degree of freedom in coloring. Gloves obtained by dip-forming latex are suitable for work such as a semiconductor device manufacturing process.

Further, the hydrogenated conjugated polymer rubber obtained from the hydrogenated conjugated polymer latex has no fear of darkening or coloring derived from platinum group elements, It can be used in a wide range of industrial applications utilizing various properties such as oiliness, weather resistance, ozone resistance, heat resistance, and cold resistance.

Claims

The scope of the claims 1. Platinum group element-containing catalyst contained in the hydrogenation reaction mixture is oxidized by contacting it with an oxidizing agent, and a complexing agent is added to the reaction mixture simultaneously with or after the addition of the oxidizing agent. A catalyst recovery method, comprising adding a complex to the mixture to separate the complex.  2. Reaction step for hydrogenating a conjugated gen-based polymer in the presence of a platinum group element-containing catalyst (A); an oxidation step of bringing a catalyst contained in a reaction mixture into contact with an oxidizing agent (B); a complexing treatment step of adding a complexing agent to the reaction mixture to form an oxidized catalyst complex (C); a catalyst recovery step of separating a complex formed from the complexed reaction mixture ( D); A method for producing a hydrogenated conjugated gen-based polymer, comprising:  3. The conjugated gen-based polymer is a homopolymer or copolymer of at least one conjugated gen monomer, or another copolymerizable monomer with the at least one conjugated gen monomer. 3. The production method according to claim 2, which is a copolymer with:  4. The production method according to claim 2, wherein the conjugated gen-based polymer is a copolymer of a conjugated gen monomer and an α, ^ monounsaturated ethylenic nitrile monomer.  5. The method according to claim 2, wherein the conjugated gen-based polymer is a copolymer of 30 to 95% by weight of Ί, 3-butadiene and 5 to 70% by weight of acrylonitrile.  6. The method according to any one of claims 2 to 5, wherein the platinum group element is palladium.  7. The production method according to any one of claims 2 to 6, wherein the hydrogenation in the step (ii) is performed under basic conditions.  8. Prior to hydrogenation in step (ii), a polymer having a weight-average molecular weight of Ί, 000-100,000, soluble or dispersible in the latex of the conjugated diene polymer The production method according to any one of claims 2 to 7, wherein the compound is added as a hydrogenation catalyst stabilizer in an amount of 0.5 to 20 times by weight based on a metal element in the hydrogenation catalyst. 9. The production method according to claim 8, wherein the polymer compound is a polymer or a polyether of a vinyl compound having a polar group in a side chain. 10. The method according to any one of claims 2 to 9, wherein the complexing agent used in step (C) is a compound of the formula:  11. The production method according to any one of claims 2 to 10, wherein the oxidizing agent used in step (B) is air, oxygen, peroxide, iodine, or a metal halide.  1 2. The production method according to any one of claims 2 to 10, wherein the oxidizing agent used in step (B) is air, hydrogen peroxide, iodine or ferric chloride.  13. The production method according to any one of claims 2 to 12, wherein an adsorbent coexists in the hydrogenation reaction mixture, and the complex formed by the complexing treatment is adsorbed to the adsorbent and separated.  14. The production method according to claim 13, wherein an adsorbent is added to the hydrogenation reaction mixture after the complexation treatment.  15. The production method according to claim 13, wherein the adsorbent is at least one selected from activated carbon, a silicon-containing inorganic compound, a synthetic zeolite, and an ion exchange resin.  1 6. The precipitate according to any one of claims 2 to 15, wherein the precipitate formed by adding the complexing agent is separated by filtration using a filtration device having a plurality of filter elements. Manufacturing method.