JP4123852B2 - Hydrogenation catalyst stabilizer, hydrogenation catalyst solution and preparation method thereof, hydrogenation reaction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydrogenation catalyst stabilizer, a catalyst solution containing the same, a preparation method thereof, and a hydrogenation reaction method in which a hydrogenation catalyst stabilizer coexists.
[0002]
[Prior art]
In the chemical industry that manufactures medical pesticides, petrochemical products, polymers, etc., it is widely practiced to hydrogenate carbon-carbon unsaturated bonds and carbon-nitrogen unsaturated bonds contained in various compounds to improve their properties. Yes.
[0003]
For example, in the polymer field, a method for selectively or partially hydrogenating a carbon-carbon double bond of a conjugated diene polymer is known as a useful modification means of the conjugated diene polymer. Hydrogenated acrylonitrile-butadiene Hydrogenated conjugated diene polymers such as copolymers are produced on an industrial scale.
[0004]
As a typical process for producing such a hydrogenated conjugated diene polymer, a monomer containing a conjugated diene is subjected to emulsion polymerization, and the resulting latex is coagulated and dried to prepare a raw material polymer. A process is known in which a coalescence is dissolved in an organic solvent, and a hydrogenation reaction is performed using a supported catalyst in which a catalyst containing a platinum group element is supported on a carrier insoluble in the organic solvent.
[0005]
In recent years, a process using an organic solvent-soluble unsupported catalyst without using a supported catalyst as described above, or an emulsion polymerization using an unsupported catalyst without undergoing the above-described steps can be obtained. Various studies have also been made on the process of directly hydrogenating a conjugated diene polymer in a latex state (for example, US Pat. No. 3,898,208, JP-A-2-178305, etc.).
[0006]
Although the hydrogenation method using such an unsupported catalyst can increase the hydrogenation rate of the reaction product with a small amount of catalyst, the hydrogenation catalyst dissolved or dispersed in the reaction system becomes stable over time. There was a problem that the catalytic activity was lowered depending on the reaction conditions.
[0007]
[Problems to be solved by the invention]
The object of the present invention is to improve the catalytic activity of the hydrogenation catalyst used and the storage stability of the catalyst solution, and to improve the hydrogenation rate of the hydride in the production of hydrides of conjugated diene polymers. .
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors have studied the hydrogenation reaction of a conjugated diene polymer, and as a result, when preparing a hydrogenation catalyst solution, the polymer is soluble in the solvent or dispersion medium of the polymer. Alternatively, by adding a specific polymer compound having a specific molecular weight that is dispersible to the catalyst solution, the catalytic activity of the hydrogenation catalyst and the storage stability of the catalyst solution are improved. The inventors have found that a diene polymer can be obtained, and have completed the present invention.
[0009]
According to the present invention,
(1) Stabilization of a hydrogenation catalyst comprising a hydrogenation catalyst containing a platinum group element and polyvinylpyrrolidone or polymethylvinylether having a weight average molecular weight of 1,000 to 100,000 in an organic solvent solution or latex of a conjugated diene polymer. A method for producing a hydrogenated conjugated diene polymer, comprising adding an aqueous hydrogenation catalyst solution containing an agent and hydrogenating the conjugated diene polymer;
(2) The method for producing a hydrogenated conjugated diene polymer according to (1), wherein the platinum group element is palladium or rhodium;
(3) After the hydrogenation catalyst aqueous solution prepares an acidic aqueous solution of the hydrogenation catalyst, basic hydrogen obtained by adding a hydrogenation catalyst stabilizer to the acidic aqueous solution and then adding a basic compound A method for producing the hydrogenated conjugated diene polymer according to the above (1) or (2), which is an aqueous solution of a hydrogenation catalyst;
(4) The method for producing a hydrogenated conjugated diene polymer according to any one of the above (1) to (3), wherein the hydrogenation reaction is carried out under basic conditions;
Is provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the method for producing the hydrogenated conjugated diene polymer of the present invention will be described in detail.
[0011]
Hydrogenation catalyst stabilizers of the present invention is characterized by comprising a soluble or dispersible polymer compound in a solvent or dispersion medium of the conjugated diene polymer. The solvent or dispersion medium of the conjugated diene polymer (hereinafter sometimes abbreviated as “medium”) is an aqueous solvent or an organic solvent. The polymer compound is soluble or dispersible in the medium (refers to a stable dispersion state like a colloid) and dissolves the hydrogenation catalyst without causing aggregation or precipitation in the medium. or all SANYO having the ability to disperse, particularly Ru water-soluble polymer compound der. Specific examples of the polymer compound, polyvinyl pyrrolidone, Po Li methyl vinyl ether.
[0012]
Moreover, the molecular weight of these high molecular compounds is a weight average molecular weight (Mw), and is 1,000-100,000, Preferably it is 2,000-50,000. When the Mw of the polymer compound is within this range, the storage stability of the catalyst solution is further improved, and the catalytic activity in the hydrogenation reaction is improved.
[0013]
The hydrogenation catalyst stabilizer of the present invention is used when a hydrogenation reaction is performed in the manufacturing field of pharmaceuticals, agricultural chemicals, industrial chemicals, petroleum, petrochemical products, polymer products, fat products, edible oils, lubricants, fragrances, and the like. It can be widely applied, the catalytic activity of the hydrogenation catalyst can be increased to reduce the amount of use thereof, and the storage stability of the catalyst solution can be improved.
[0014]
The hydrogenation catalyst stabilizer is suitable for stabilization of an unsupported hydrogenation catalyst among hydrogenation catalysts, and more preferably for stabilization of a hydrogenation catalyst containing a platinum group element. .
[0015]
Examples of platinum group elements include ruthenium, rhodium, palladium, osmium, iridium, and platinum, and the hydrogenation catalyst is a compound containing these platinum group elements. Among these, a palladium compound and a rhodium compound are preferable from the viewpoint of catalytic activity and availability, and a palladium compound is more preferable. Moreover, although the hydrogenation catalyst may contain 2 or more types of platinum group element compounds, it is preferable to use a palladium compound as the main catalyst component also in that case.
[0016]
As the palladium compound, a II-valent or IV-valent palladium compound is usually used, and the form thereof is a salt or a complex salt.
[0017]
Examples of the palladium compound include organic acid salts such as palladium acetate, palladium formate and palladium propionate; inorganic acid salts such as palladium nitrate and palladium sulfate; halogens such as palladium fluoride, palladium chloride, palladium bromide and palladium iodide. Inorganic palladium compounds such as palladium oxide and palladium hydroxide; Organic palladium compounds such as dichloro (cyclooctadiene) palladium, dichloro (norbornadiene) palladium and dichlorobis (triphenylphosphine) palladium; Sodium tetrachloropalladate, hexachloropalladium acid Halogenated salts such as ammonium; complex salts such as potassium tetracyanopalladate;
Among these palladium compounds, organic acid salts or inorganic acid salts such as palladium acetate, palladium nitrate and palladium sulfate; palladium chloride; halide salts such as sodium tetrachloropalladate and ammonium hexachloropalladate; More preferred are palladium, palladium nitrate and palladium chloride.
[0018]
Examples of rhodium compounds include halides such as rhodium chloride, rhodium bromide, and rhodium iodide; inorganic acid salts such as rhodium nitrate and rhodium sulfate; rhodium acetate, rhodium formate, rhodium propionate, rhodium butyrate, rhodium valerate, and naphthenic acid. Organic acid salts such as rhodium and rhodium acetylacetonate; rhodium oxide; rhodium trihydroxide;
[0019]
The hydrogenation catalyst stabilizer of the present invention 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 subjected to a hydrogenation reaction. In this case, the concentration of the polymer compound in the catalyst solution is preferably 0.5 to 20 times by weight, more preferably 1 to 10 times by weight with respect to the metal element in the hydrogenation catalyst.
[0020]
When the catalyst solution is an aqueous solution, for example, inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, bromic acid, perchloric acid and phosphoric acid; metal salts such as sodium salts and potassium salts of these inorganic acids; organic such as acetic acid The coexistence of acid; etc. may improve 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 by mole, more preferably 1 to 10 times by mole with respect to the metal element in the hydrogenation catalyst.
[0021]
Even if the catalyst aqueous solution is allowed to stand at 25 ° C. for 1 hour or longer, preferably 1 day or longer, more preferably 14 days or longer after preparation, the hydrogenation catalyst does not aggregate or precipitate.
[0022]
In particular, the method for preparing the catalyst aqueous solution preferably includes a step of adding the hydrogenation catalyst stabilizer of the present invention to the aqueous solution following the step of preparing an acidic aqueous solution of the hydrogenation catalyst.
[0023]
By allowing the hydrogenation catalyst stabilizer of the present invention to exist in a medium in which the hydrogenation catalyst is dissolved or dispersed, the compound to be hydrogenated can be hydrogenated at a high hydrogenation rate. That is, as a further invention, a hydrogenation reaction method is provided in which a hydrogenation target compound is hydrogenated in a medium in which a hydrogenation catalyst is dissolved or dispersed in the presence of the hydrogenation catalyst stabilizer of the present invention. Representative examples of the hydrogenation reaction to which the method can be applied include partial hydrogenation of acetylene to ethylene, partial hydrogenation of 3-hexyn-1-ol to cis-3-hexen-1-ol, and the like. Hydrogenation reaction of acetylene bond to carbon-carbon double bond; gasoline hydrogenation (gasoline quality improvement), production of isooctane from diisobutylene, production of saturated glyceride from unsaturated glyceride, from conjugated diene polymer Hydrogenation reaction of carbon-carbon double bonds to saturated bonds, such as the production of hydrogenated conjugated diene polymers; Hydrogenation reaction of carbonyl groups to produce corresponding alcohols from cyclopentanone and cyclohexanone; Nitrile groups And a hydrogenation reaction for converting an azomethine group (Schiff base) into an amino group.
[0024]
In the hydrogenation reaction, the hydrogenation catalyst stabilizer of the present invention may be added directly to the reaction system. However, it is preferable to prepare the catalyst solution in advance as described above before adding it to the reaction system.
[0025]
Among the various hydrogenation reactions described above, the hydrogenation reaction method of the present invention is particularly preferably applicable to a method for producing a hydrogenated conjugated diene polymer.
Specific embodiments of the hydrogenation reaction method using the catalyst stabilizer of the present invention, such as specific operations and conditions, will be described below by taking the hydrogenation reaction of a conjugated diene polymer as an example.
[0026]
The conjugated diene polymer is a combination of one or more conjugated diene monomers or one or more monomers copolymerizable with the conjugated diene monomer with one or more conjugated diene monomers. It is produced by a conventionally known emulsion polymerization method or solution polymerization method, preferably by an emulsion polymerization method.
[0027]
The conjugated diene monomer is not particularly limited. For example, 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 2-chloro- Examples include 1,3-butadiene and 1,3-pentadiene. Among these, 1,3-butadiene and 2-methyl-1,3-butadiene are preferable, and 1,3-butadiene is more preferable.
[0028]
Examples of the monomer copolymerizable with the conjugated diene monomer include α, β-ethylenically unsaturated nitrile monomers such as acrylonitrile, methacrylonitrile, crotonnitrile, vinylidene cyanide; acrylic acid, methacrylic acid , Crotonic acid, fumaric acid, maleic acid, itaconic acid and other α, β-ethylenically unsaturated carboxylic acids and their anhydrides; methyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, trifluoroacrylate Α, β-ethylenically unsaturated carboxylic acid esters such as ethyl, methyl methacrylate and methyl crotonic acid; α, β-ethylenically unsaturated carbonamides such as acrylamide and methacrylamide; styrene, α-methylstyrene, p-methyl Vinyl aromatic compounds such as styrene, divinylbenzene, and vinylpyridine ; Vinylether compounds such as fluoroethyl vinyl ether; vinyl acetate, vinyl esters such as vinyl propionate and the like.
[0029]
Among these monomers, from the viewpoint of facilitating the hydrogenation reaction in the present invention, a monomer having an electron-withdrawing functional group is preferable, and an α, β-unsaturated nitrile monomer, particularly acrylonitrile is preferably used. It is done.
[0030]
Specific examples of the conjugated diene polymer to which the hydrogenation reaction of the present invention can be applied include butadiene polymer, isoprene polymer, butadiene-styrene copolymer, acrylonitrile-butadiene copolymer, acrylonitrile-isoprene copolymer, acrylonitrile. -Butadiene-isoprene copolymer, methacrylonitrile-butadiene copolymer, methacrylonitrile-isoprene copolymer, methacrylonitrile-butadiene-isoprene copolymer, acrylonitrile-methacrylonitrile-butadiene copolymer, acrylonitrile-butadiene-acrylic acid Examples thereof include a methyl copolymer and an acrylonitrile-butadiene-acrylic acid copolymer.
Among the conjugated diene polymers, the method of the present invention can be suitably applied to acrylonitrile-butadiene copolymer and methacrylonitrile-butadiene copolymer from the viewpoint of practicality of hydrogenated copolymer. It can be most suitably applied to an acrylonitrile copolymer.
[0031]
The monomer composition ratio in the conjugated diene polymer is not particularly limited, but it is 5 to 100% by weight of the conjugated diene monomer, and 95 to 0% by weight of the monomer copolymerizable therewith. It is 10 to 90% by weight of a monomer, and 90 to 10% by weight of a monomer copolymerizable therewith. The weight average molecular weight (measured by gel permeation chromatography and calculated in terms of standard polystyrene) is not particularly limited, but is usually 5,000 to 500,000.
[0032]
An emulsion polymerization method suitable as a method for preparing a conjugated diene polymer (raw material) is generally carried out in an aqueous medium using a radical polymerization initiator, and known polymerization initiators and molecular weight regulators can be used. That's fine. The polymerization reaction may be any of batch, semi-batch and continuous, and the polymerization temperature and pressure are not particularly limited. The emulsifier to be used is not particularly limited, and an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, and the like can be used, and an anionic surfactant is preferable. These emulsifiers may be used alone or in combination of two or more. The amount used is not particularly limited.
[0033]
The solid content concentration of the conjugated diene 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 solid content concentration can be appropriately adjusted by a known method such as a blending method, a dilution method, or a concentration method.
[0034]
When the hydrogenation reaction of the present invention is carried out in a latex state (hereinafter also referred to as “latex hydrogenation”), the solid content concentration of the latex can be adjusted to a range of 10 to 50% by weight from the viewpoint of reaction efficiency. More preferred.
[0035]
The hydrogenation reaction of the present invention is also performed in the state of a polymer solution in which a conjugated diene polymer rubber obtained by coagulating and drying a latex obtained by emulsion polymerization is dissolved in an appropriate organic solvent (hereinafter referred to as “solution”). Also called "system hydrogenation").
In this case, the latex can be coagulated and dried by a known method, but by providing a treatment step for bringing the crumb obtained by coagulation into contact with a basic aqueous solution, the resulting conjugated diene polymer rubber is treated with tetrahydrofuran ( It is preferable to modify so that the pH of the polymer solution measured by dissolving in THF) exceeds 7. The pH of the polymer solution measured by dissolving in THF is preferably in the range of 7.2 to 12, more preferably 7.5 to 11.5, and most preferably 8 to 11. By this contact treatment between the crumb and the basic aqueous solution, the solution-based hydrogenation can be rapidly advanced.
[0036]
The solution concentration of the conjugated diene polymer in the solution hydrogenation is 1 to 70% by weight, preferably 2 to 40% by weight. Examples of the organic solvent that is a medium used for solution hydrogenation include linear or cyclic aliphatic hydrocarbons such as n-hexane, cyclohexane, and n-heptane; aromatic carbons such as benzene, toluene, xylene, and chlorobenzene. Hydrogen; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone; ethers such as diethyl ether, tetrahydrofuran, dioxane, anisole; esters such as ethyl acetate And so on. Of these organic solvents, ketones are preferably used.
[0037]
As the hydrogenation catalyst, in both latex hydrogenation and solution hydrogenation, a non-supported catalyst in which a catalyst component is dissolved or dispersed in a reaction medium without supporting a catalyst component on a carrier is used.
[0038]
In the hydrogenation reaction, the hydrogenation catalyst can be added to the reaction system by directly adding it to the reaction system and dissolving or dispersing it in a medium; preliminarily dissolved or dispersed in water or an organic solvent, and the state of the catalyst solution And the method of adding to the reaction system. The latter method is more practical in terms of operability.
[0039]
The temperature of the hydrogenation reaction is usually 0 ° C to 200 ° C, preferably 5 ° C to 150 ° C, more preferably 10 to 100 ° C. If the reaction temperature is excessively high, decomposition of the compound to be hydrogenated or a side reaction may occur, which is not desirable. On the other hand, when the reaction temperature is excessively lowered, the reaction rate is lowered, which is not practical.
[0040]
The pressure of hydrogen is usually 0.1 MPa to 20 MPa, preferably 0.1 MPa to 15 MPa, more preferably 0.1 MPa to 10 MPa. Although reaction time is not specifically limited, Usually, it is 30 minutes-50 hours. The hydrogen gas is preferably pressurized after first substituting the reaction system with an inert gas such as nitrogen and further substituting with hydrogen.
[0041]
In the case of a hydrogenation reaction of a conjugated diene polymer, the reaction efficiency is further improved by performing the latex and solution hydrogenation reactions under basic conditions, and the amount of hydrogenation catalyst used can be reduced. The method for carrying out the reaction under basic conditions is not particularly limited, and can be appropriately selected according to each reaction system of latex hydrogenation and solution hydrogenation.
In solution-based hydrogenation, as described above, in the step of preparing a conjugated diene polymer rubber (raw material) to be subjected to a hydrogenation reaction, the polymer is brought into contact with a basic aqueous solution; hydrogenation reaction And a method of adding a basic compound to the reaction system after initiation.
Furthermore, a method of adding a basic compound at the stage of preparing the catalyst solution can be employed for both latex hydrogenation and solution hydrogenation. Note that when an inorganic acid or the like is used to promote dissolution of the catalyst in water, a basic compound in an amount equal to or more than neutralizing it is added to the catalyst aqueous solution.
[0042]
The basic compound for making the hydrogenation reaction solution or the catalyst solution basic is not particularly limited, and examples thereof include alkali metal compounds, alkaline earth metal compounds, ammonia, ammonium salt compounds, and organic amine compounds. Preferred are alkali metal compounds and alkaline earth metal compounds.
[0043]
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, potassium hydrogen carbonate, and the like. A bicarbonate compound is preferably used, and more preferably a hydroxide.
As the alkaline earth metal compound, an alkaline earth metal hydroxide such as magnesium, calcium, strontium, barium, a carbonate compound, a bicarbonate compound, or the like is preferably used, and more preferably a hydroxide.
Examples of the ammonium salt compound include ammonium carbonate and ammonium bicarbonate; examples of the organic amine compound include triethylamine, ethanolamine, morpholine, N-methylmorpholine, pyridine, hexamethylenediamine, dodecamethylenediamine, xylylenediamine, and the like. The
[0044]
These basic compounds can be used as they are, or can be used by diluting or dissolving them in water or an organic solvent such as alcohol or ketone. The basic compound 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 and the catalyst solution exhibit basicity.
[0045]
For example, in the case of a conjugated diene polymer, the hydrogenation rate of the hydride obtained by the hydrogenation method of the present invention can be 90% or more and 95% or more depending on the conditions.
Moreover, since the quantity of the hydrogenation catalyst to be used can be reduced by using the method of this invention, the amount of residual platinum group elements in the obtained hydride can be reduced. The amount of residual platinum group element in the hydride obtained by the method of the present invention is usually 200 ppm or less, and can be reduced to 100 ppm or less if the amount of catalyst is further reduced by reaction under basic conditions or the like. .
[0046]
In order to efficiently recover the used hydrogenation catalyst from the reaction mixture obtained by the hydrogenation reaction method of the present invention, the platinum group element of the hydrogenation catalyst in the reaction mixture is complexed with a complexing agent. Is preferred. In the case of latex hydrogenation reaction of conjugated diene polymer, for example, the complexed product produced by the complexing treatment is precipitated in the reaction mixture and can be separated and recovered by filtration or centrifugation. In the case of a solution-based hydrogenation reaction of the same polymer, it is easily adsorbed on an adsorbent or the like, and can be adsorbed on the adsorbent and separated and recovered. The amount of residual platinum group element in the hydride can be further reduced by this complexing treatment and separation / recovery operation.
[0047]
Examples of such a complexing agent include oxime compounds in the case of latex hydrogenation of conjugated diene polymers, and ammonia and ammonium acetate in the case of solution hydrogenation.
[0048]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples. Further, parts and% in these examples are based on weight unless otherwise specified.
[0049]
The hydrogenation rate of the hydrogenated conjugated diene polymer was measured by proton NMR. The amount of palladium in the hydrogenated conjugated diene polymer after separation and recovery of the hydrogenation catalyst is determined by atomic absorption spectrometry by dissolving a part of the hydrogenated polymer in carbonic acid / ashing at 600 ° C. and then dissolving in sulfuric acid. It was measured by.
The catalyst storage stabilization performance of the catalyst stabilizer was evaluated by allowing the prepared catalyst solution (containing the stabilizer in the examples) to stand at 25 ° C. for 1 hour to 14 days to aggregate the catalyst. The presence or absence of precipitation was observed visually.
[0050]
Reference example 1
An autoclave was charged with 2 parts of potassium oleate, 180 parts of ion exchanged water, 37 parts of acrylonitrile, and 0.5 part of t-dodecyl mercaptan. After replacing the inside of the reactor with nitrogen, 63 parts of butadiene was sealed. The reactor was cooled to 10 ° C., and 0.01 parts of cumene hydroperoxide and 0.01 parts of ferrous sulfate were added. The contents were then allowed to polymerize with stirring for 16 hours while maintaining the reactor at 10 ° C. Thereafter, 10% hydroquinone aqueous solution was added into 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.
[0051]
Example 1
Palladium acetate (the amount used is 700 ppm in the ratio of Pd metal / NBR) was added to water, and 5-fold molar equivalent of nitric acid was added to palladium to prepare 300 parts of an acidic aqueous palladium solution. Polyvinylpyrrolidone having a weight average molecular weight of 5000 was added to the aqueous solution 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.
[0052]
Put 400 parts of NBR latex adjusted to 30% of total solids (120 parts of solids) and the total amount of catalyst aqueous solution A in an autoclave with a stirrer, and then flow nitrogen gas for 10 minutes to remove dissolved oxygen in the latex. did. After the system was replaced with hydrogen gas twice, 3 MPa hydrogen was pressurized. The contents were heated to 50 ° C. and stirred for 6 hours to conduct a hydrogenation reaction, thereby obtaining a latex-state hydrogenated NBR reaction mixture.
[0053]
2 parts of 30% hydrogen peroxide water was added to the latex reaction mixture and stirred (oxidation treatment) at 80 ° C. for 2 hours. Next, the pH of the reaction mixture was adjusted to 9.5, and dimethylglyoxime corresponding to a 5-fold 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), insoluble matters were precipitated in the latex. The total amount of the latex was suction filtered to separate the precipitate. The resulting white filtrate was concentrated under reduced pressure using a rotary evaporator to obtain solid hydrogenated NBR. The hydrogenation rate of hydrogenated NBR was 93%. In addition, as a result of separately evaluating the storage stability of the same catalyst aqueous solution A used for hydrogenation, no aggregation or precipitation was confirmed even after standing at 25 ° C. for 14 days.
The amount of palladium in hydrogenated NBR was 37 ppm.
[0054]
Comparative Example 1
The hydrogenation reaction and the recovery of the hydrogenated polymer were performed in the same manner as in Example 1 except that polyvinyl pyrrolidone was not added to the hydrogenation catalyst solution A. The hydrogenation rate of hydrogenated NBR reached only 70%. In addition, as a result of evaluating the storage stability of the catalyst aqueous solution A used for the hydrogenation, a slight precipitate was observed at the time of standing at 25 ° C. for 1 hour.
[0055]
Reference example 2
In the same manner as in Reference Example 1, acrylonitrile-butadiene copolymer (NBR) latex was prepared. While stirring 300 parts of coagulated water dissolving 3 parts of calcium chloride (coagulant) at 50 ° C., the latex was added dropwise to 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.
[0056]
Example 2
As in Example 1, palladium acetate (the amount used is 700 ppm in the ratio of Pd metal / NBR) is added to water, and 5-fold molar equivalent of nitric acid is added to palladium to prepare 300 parts of an acidic aqueous palladium solution. did. Polymethylvinyl ether having a weight average molecular weight of 3,000 was added to the aqueous solution 5 times by weight with respect to palladium. Further, an aqueous potassium hydroxide solution was added to prepare an aqueous catalyst solution B having a pH of 9.0.
The palladium acetate aqueous solution B (the amount used is a Pd metal / NBR ratio of 500 ppm) is added to 800 parts of an acetone solution of the polymer (solid content: 120 parts), and the mixture is put into an autoclave with a stirrer, and nitrogen gas is added to 10 parts. Flowed for 5 minutes to remove dissolved oxygen. After the system was replaced with hydrogen gas twice, 5 MPa hydrogen was pressurized. The contents were heated to 50 ° C. and stirred for 6 hours to conduct a hydrogenation reaction.
[0057]
After completion of the hydrogenation reaction, the system was cooled to room temperature, and the hydrogen in the system was replaced with nitrogen. To this reaction mixture, 1.84 parts of ferric chloride was added and stirred (oxidation treatment) at 30 ° C. for 3 hours. Next, 16 parts of aqueous ammonia was added and stirred at 80 ° C. for 5 hours (complexation treatment). After cooling, 6 parts of activated carbon was added and stirred (adsorption treatment) at room temperature for 3 hours, 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 in a vacuum dryer for 24 hours to obtain hydrogenated NBR. The hydrogenation rate of hydrogenated NBR was 95%. In addition, as a result of evaluating the storage stability of the catalyst aqueous solution B used for the hydrogenation, no aggregation or precipitation was confirmed even after standing at 25 ° C. for 14 days. The amount of palladium in the hydrogenated NBR was 50 ppm.
[0058]
Comparative Example 2
The hydrogenation reaction and the recovery of the hydrogenated polymer were performed in the same manner as in Example 2 except that polymethylvinyl ether was not added to the hydrogenation catalyst solution B. The hydrogenation rate of hydrogenated NBR reached only 85%. In addition, as a result of evaluating the storage stability of the catalyst aqueous solution A used for hydrogenation, the catalyst was completely deposited and precipitated at the time of standing at 25 ° C. for 1 hour.
[0059]
As is clear from the above Examples and Comparative Examples, in Comparative Examples 1 and 2 in which no catalyst stabilizer was allowed to coexist during the hydrogenation reaction, the hydrogenation addition rate of the hydrogenated conjugated diene polymer However, when the catalyst aqueous solution was stored for a long period of time, the catalyst was precipitated or precipitated. In contrast, in Examples 1 and 2 where the hydrogenation reaction was performed in the presence of a catalyst stabilizer, the hydrogenation rate of the hydrogenated conjugated diene polymer reached 90% or more, Even after long-term storage, it was still uniformly dissolved.
[0060]
【The invention's effect】
When a hydrogenation reaction is carried out in the presence of a hydrogenation catalyst containing a platinum group element using the hydrogenation catalyst stabilizer of the present invention, a hydride having a high hydrogenation rate can be obtained with a small amount of hydrogenation catalyst used. it can. That is, the activity of the hydrogenation catalyst can be improved, and the amount of catalyst used can be reduced. Moreover, the hydrogenation catalyst solution using the hydrogenation catalyst stabilizer of the present invention is excellent in storage stability. Therefore, a large amount of catalyst solution can be prepared at a time and used sequentially for the hydrogenation reaction.

Claims (4)

The organic solvent solution or latex of the conjugated diene polymer, the hydrogenation catalyst stabilizer hydrogenation catalyst and a weight average molecular weight of polyvinyl pyrrolidone or polymethyl vinyl ether of from 1,000 to 100,000 containing platinum group elements A method for producing a hydrogenated conjugated diene polymer, comprising adding an aqueous hydrogenation catalyst solution to hydrogenate the conjugated diene polymer. The method for producing a hydrogenated conjugated diene polymer according to claim 1, wherein the platinum group element is palladium or rhodium. After the hydrogenation catalyst aqueous solution is prepared as an acidic aqueous solution of the hydrogenation catalyst, a basic hydrogenation catalyst aqueous solution obtained by adding a hydrogenation catalyst stabilizer to the acidic aqueous solution and then adding a basic compound. The method for producing a hydrogenated conjugated diene polymer according to claim 1 or 2. The method for producing a hydrogenated conjugated diene polymer according to any one of claims 1 to 3, wherein the hydrogenation reaction is performed under basic conditions.