JP2002308905A - Method for manufacturing hydrogenated diene-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogenated diene-based polymer manufacturing method capable of efficiently removing a catalyst after hydrogenation reaction and capable of lessening the inference of discharged waste water on the environment. SOLUTION: In this method for manufacturing the hydrogenated diene-based polymer, hydrogenation proceeds in a hydrocarbon solvent in the presence of a hydrogenation catalyst comprising an 8 or 10 group transition metal compound and an organic aluminum compound, the reaction mixture is then treated with an oxidizing agent and next with an organic and/or inorganic acid, and then washed in water to dissolve the 8-10 group transition metal and aluminum in the hydrogenation catalyst into the water to be removed. The method is characterized in that a nonaqueous alcohol is added to the reaction mixture at least at one stage between the treatment with the oxidizing agent and the washing in water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a hydrogenated diene polymer, and more particularly to a method for removing a hydrogenation catalyst (= hydrogenation catalyst) from a hydrogenated diene polymer reaction mixture. The present invention relates to a method for producing a hydrogenated diene polymer.

[0002]

2. Description of the Related Art In producing a hydrogenated diene polymer by hydrogenating a diene polymer, a Raney nickel catalyst; a metal such as nickel, platinum, palladium, ruthenium or rhodium is used as a hydrogenation catalyst. Catalyst supported on a carrier such as alumina, diatomaceous earth or the like; bis (cyclopentadienyl) metal compound containing a transition metal belonging to Group 4 such as titanium, zirconium or hafnium and lithium, potassium or aluminum , A homogeneous catalyst comprising a metal compound containing zinc or magnesium as a constituent; or nickel, cobalt,
A heterogeneous catalyst comprising a metal compound containing a transition metal of Group 8 to Group 10 such as iron as a constituent and an organic aluminum compound such as triethylaluminum or triisobutylaluminum is generally used. From the viewpoint of maintaining the hue of the obtained hydrogenated diene-based polymer and various physical properties such as thermal stability, these hydrogenation catalyst components are removed from the product hydrogenated diene-based polymer. It is required that the residual amount of the metal component derived from the hydrogenation catalyst in the added diene-based copolymer be reduced as much as possible.

When the above-mentioned solid catalyst is used as a hydrogenation catalyst for hydrogenating a diene polymer, it is possible to remove the solid catalyst by directly filtering the reaction mixture after the hydrogenation reaction. . In the case of using the above-mentioned homogeneous catalyst, the amount of the catalyst used is generally extremely small. Usually, it is not necessary to remove such catalysts, since they do not adversely affect the physical properties. On the other hand, when using a heterogeneous catalyst,
It is generally necessary to remove it from the reaction mixture after the hydrogenation reaction because it is used in a larger amount than a homogeneous catalyst, but since the particle size is extremely small compared to a solid catalyst, it is removed by filtration like a solid catalyst. It is difficult to do.

[0004] As a method for removing the above-mentioned heterogeneous catalyst used as a hydrogenation catalyst from the reaction mixture after hydrogenation of the diene polymer, the reaction mixture containing the hydrogenation catalyst is treated with an oxidizing agent, and the reaction mixture is treated with an organic compound. There is known a method of treating with an acid or an inorganic acid and then removing it by washing with water. Also,
U.S. Pat. No. 3,780,138 describes that a lower aliphatic alcohol is used in combination with an oxidizing agent after the acid treatment in the above method. According to the U.S. Patent Publication, by using a lower aliphatic alcohol in combination,
It is shown that the metal components constituting the heterogeneous catalyst can be removed more efficiently than when no lower aliphatic alcohol is used. However, in this method, since the lower aliphatic alcohol is water-soluble, most of the lower aliphatic alcohol is contained in the washing wastewater, and the COD in the wastewater is thereby reduced.
There is a problem of environmental pollution such as the increase of

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art. In a method for producing a hydrogenated diene polymer, there is provided a method for removing a hydrogenation catalyst component after a hydrogenation reaction. It is an object of the present invention to provide a method for producing a hydrogenated diene-based polymer, which can efficiently carry out the above-mentioned process, and has less influence on the environment of wastewater generated in the removal step.

[0006]

SUMMARY OF THE INVENTION According to the present invention, the object is to provide a diene polymer in a hydrocarbon solvent containing a metal compound containing a Group 8 to Group 10 transition metal and an organoaluminum compound. After hydrogenation using a hydrogenation catalyst consisting of the following, the reaction mixture is treated with an oxidizing agent, treated with an organic acid and / or an inorganic acid, and then washed with water. A method for solubilizing and removing a Group 10 transition metal and aluminum to obtain a hydrogenated diene polymer, wherein a water-insoluble alcohol is added to the reaction mixture in at least one stage from oxidizing agent treatment to water washing. The problem is solved by a method for producing a hydrogenated diene polymer characterized by the following.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. First, the diene polymer used as a raw material in the present invention will be described. Examples of the diene-based polymer include a conjugated diene homopolymer, a copolymer of two or more conjugated dienes, and a copolymer of at least one conjugated diene and at least one monomer copolymerizable with the conjugated diene. Is mentioned. Examples of the copolymerization mode include random copolymerization, block copolymerization, and graft copolymerization, but are not limited thereto, and any mode may be used. The form of the diene polymer molecule is not particularly limited, and may be any form such as linear or branched. Further, there is no particular limitation on the microstructure of the conjugated diene portion in the diene polymer.

The above conjugated diene includes, for example, 1,
3-butadiene, isoprene, 1,3-pentadiene,
2,3-dimethyl-1,3-butadiene, 2-methyl-
1,3-pentadiene, 1,3-hexadiene, 4,5
-Diethyl-1,3-octadiene, 3-butyl-1,
3-octadiene and the like. Among these,
1,3-butadiene and isoprene are preferably used.

Examples of the monomer copolymerizable with the conjugated diene include styrene, α-methylstyrene, p-methylstyrene, t-butylstyrene, 1-vinylnaphthalene, 3-methylstyrene, 4-propylstyrene,
Cyclohexylstyrene, 4-dodecylstyrene, 2-
Ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, cumarone, indene, vinylpyridine,
Vinylfuran, acrylonitrile, ethyl acrylate, methyl acrylate, methyl methacrylate, t-
Butyl methacrylate, hydroxyethyl methacrylate, acrylic acid, methacrylic acid and the like. Of these, styrene is preferably used.

The diene polymer used in the present invention also includes a modified diene polymer in which a functional group such as a hydroxyl group, a carboxyl group, an epoxy group, or an amino group is introduced in the molecular chain or at the molecular terminal. I do. Such a modified diene polymer, for example, in the presence of a radical generator such as a peroxide, an unsaturated carboxylic acid derivative or an anhydride thereof with a diene polymer, or a solution or melt of the diene polymer. It can be produced by reacting in the state. Such a modified diene-based polymer can also be produced by introducing the above-mentioned functional group to the molecular terminal using the reactivity of the polymer terminal of the diene-based polymer.

The number average molecular weight of the diene polymer used in the present invention is not particularly limited, but is generally 500 to 500.
It is in the range of 2,000,000. Here, the number average molecular weight is a number average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

Next, the hydrogenation catalyst used in the present invention will be described. In the present invention, when hydrogenating the diene polymer, a hydrogenation catalyst comprising a metal compound containing a Group 8 to Group 10 transition metal and an organoaluminum compound is used. As the transition metals of Group 8 to Group 10, for example, nickel, cobalt, iron and the like are used. As the metal compound containing a transition metal of Group 8 to Group 10 as a constituent, various forms such as a carboxylate and a complex salt with acetylacetone can be used. Examples of the carboxylate include Group 8 to Group 1
Group 0 transition metal and naphthenic acid, 2-ethylhexanoic acid,
Examples thereof include salts with octanoic acid, 2-methyloctanoic acid, nonanoic acid, linoleic acid, oleic acid, myristic acid, palmitic acid, stearic acid, benzoic acid, t-butylbenzoic acid, and the like. As complex salts with acetylacetone,
For example, acetylacetone nickel complex, acetylacetone cobalt complex, acetylacetone iron complex and the like can be mentioned. Among them, nickel 2-ethylhexanoate, nickel acetylacetone complex, cobalt 2-ethylhexanoate, and acetylacetone cobalt complex are preferred. The metal compound containing a transition metal belonging to Group 8 to Group 10 may be used alone or in combination of two or more.

Another component of the hydrogenation catalyst is an organoaluminum compound. As the organic aluminum compound,
Is represented by the general formula A1 (R) _3, compound R is an alkoxyl group of the alkyl group or C2-20 C2-20, represented by the general formula A1R ¹ R ² R ^3, R ^1, R ² and R ³
Is an alkyl group having 2 to 20 carbon atoms or a chlorine atom, and one or two of R ¹ , R ² and R ³ are chlorine atoms. Specific examples include triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, monochlorodiethylaluminum, and dichloroethylaluminum. These organoaluminum compounds may be used alone or in combination of two or more.

In the hydrogenation catalyst used in the present invention, the mixing ratio of the metal compound containing a Group 8 to Group 10 transition metal to the organoaluminum compound is generally a molar ratio of The metal compound containing a transition metal of Group 8 to Group 10 as a constituent: the organoaluminum compound = 1: 0.5 to 1:20. When the mixing ratio of the organoaluminum compound is less than 0.5 mol per 1 mol of the metal compound containing a transition metal of Group 8 to Group 10, the activity of the hydrogenation reaction is not sufficiently obtained. On the other hand, when the amount is more than 20 mol, not only the activity of the hydrogenation reaction becomes low, but also the molecular cleavage of the hydrogenated diene polymer tends to occur.

The amount of the hydrogenation catalyst used in the present invention is not strictly limited, and hydrogenation reaction conditions such as reaction temperature, hydrogen pressure, type of diene polymer, and concentration of diene polymer, Although it depends on the required hydrogenation rate and the like, generally, the group 8 to group 8 as a hydrogenation catalyst constituent component relative to the number of moles of the carbon-carbon double bond based on the conjugated diene unit in the diene polymer. It is preferable to use the group 10 transition metal in an amount of 0.001 to 10 mol%,
It is more preferable to use it in the range of 0.005 to 5 mol%.

Next, the hydrocarbon solvent used in the present invention will be described. The hydrocarbon solvent is not particularly limited as long as it is inert to the hydrogenation catalyst used in the present invention and is also inert to the hydrogenation reaction. Examples thereof include aliphatic hydrocarbons and oils. And cyclic hydrocarbons.
Although aromatic hydrocarbons such as benzene and toluene can be used, depending on the conditions of the hydrogenation reaction, they themselves may be hydrogenated, and care must be taken when using them. Among aliphatic hydrocarbons and alicyclic hydrocarbons, pentane, hexane, heptane, cyclohexane and the like are preferably used because of their ease of removal. These solvents may be used alone or in combination of two or more. The amount of the hydrocarbon solvent to be used is not particularly limited, but is usually 10 to 100 parts by mass of the diene polymer.
5,000 parts by mass, preferably 40 to 2 parts by mass.
More preferably, the amount is in the range of 000 parts by mass.

Further, the above-mentioned hydrocarbon solvent is used for producing a diene-based polymer for the purpose of controlling the microstructure of the diene portion and / or when copolymerizing two or more kinds of monomers containing a conjugated diene. Polar compounds used for controlling the distribution of monomers, for example, amine compounds such as triethylamine, N, N, N ', N'-tetramethylethylenediamine; diethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, 1,4 -An ether compound such as dioxane or tetrahydrofuran may be contained at all. When these polar compounds are contained in the hydrocarbon solvent, the ratio thereof is not particularly limited, but is preferably about 30% by mass or less.

The hydrogenation reaction in the present invention can be carried out by a conventional method. Generally, a hydrogen pressure of from normal pressure to 20 MPa and a reaction temperature of from normal temperature to 250 ° C. are 0.1 to 10 at a reaction temperature.
Performed for 0 hours.

The reaction mixture thus obtained can be treated with an oxidizing agent, treated with an organic acid and / or an inorganic acid, and then washed with water to obtain a hydrogenated diene polymer. Adding a water-insoluble alcohol to the reaction mixture in at least one stage from the oxidizing agent treatment to the water washing.

First, the oxidizing agent used in the present invention will be described. The treatment with the oxidizing agent is performed to oxidize the hydrogenation catalyst to facilitate the formation of a metal salt when subsequently treated with an organic acid and / or an inorganic acid. The oxidizing agent to be used is not particularly limited, but is preferably such that no organic component is mixed into the wastewater, and examples thereof include air, oxygen, and an aqueous solution of hydrogen peroxide.

The oxidizing agent is used in an amount of 1 mol based on the total number of moles of the metal in the metal compound containing a transition metal of Group 8 to Group 10, which is a component of the hydrogenation catalyst, and the aluminum in the organoaluminum compound. It may be used in a molar amount of at least twice, and there is no particular upper limit to the amount used, but it is preferable to use it in a range of about 1 to 200 times by mol. The oxidation treatment is not particularly limited as long as the hydrogenation catalyst and the oxidizing agent are in contact with each other.
A predetermined amount of an oxidizing agent is added to the reaction mixture after the hydrogenation reaction, and the mixture is stirred at a temperature of 0 to 100 ° C. for 5 minutes to 10 hours.

Next, the organic acids and inorganic acids used in the present invention will be described. The organic acid may be any one that is soluble in water, and any of the hydrocarbon solvents used in the hydrogenation reaction, and includes, for example, acetic acid, propionic acid, oxalic acid, citric acid, and the like, but is not particularly limited thereto. It is not something to be done. Specific examples of the inorganic acid include, but are not limited to, hydrochloric acid, sulfuric acid, and phosphoric acid, and any known inorganic acid can be arbitrarily used. The above organic acids and inorganic acids may be used alone or in combination of two or more.

The amount of the acid used may be selected from the group 8 to group 10 transition metal contained in the metal compound containing a group 8 to group 10 transition metal in the hydrogenation catalyst used in the present invention, and the amount of the organic compound. There is no particular limitation as long as it is at least equimolar with respect to the total number of moles of aluminum contained in the aluminum compound. The acid treatment is not particularly limited as long as the metal component in the hydrogenation catalyst oxidized by the oxidation treatment is in contact with the acid, but usually, a predetermined amount of acid is added to the reaction mixture after the oxidation treatment, 0-100 ° C
The stirring is performed in the temperature range of 5 minutes to 10 hours. When the acid is added, the acid may be added as it is, or may be added in the form of an aqueous acid solution.

In the water washing, water is usually added to the reaction mixture after the treatment with an organic acid and / or an inorganic acid, and the mixture is stirred and then allowed to stand to be separated into two phases, an organic phase and an aqueous phase. Removal can be performed. The amount of water used for water washing and the temperature of water washing are not particularly limited, but the amount of water used is usually in the range of 0.1 to 10 times the mass of the reaction mixture after acid treatment, and the temperature of water washing is usually It is in the range of 20-100 ° C. Although the number of times of washing is not particularly limited, it is usually 1 to 10 times.
It is preferably in the range of the number of times, and is preferably performed until the pH after water washing becomes substantially neutral.

Next, the water-insoluble alcohol used in the present invention will be described. When a water-insoluble alcohol is used, the catalyst metal can be removed more efficiently than when it is not used. The water-insoluble alcohol to be used is not particularly limited as long as it is an alcohol having 6 or more carbon atoms and a solubility in water of less than 1% by mass, but from the viewpoint of easy removal from the produced hydrogenated diene polymer. To C6 to C10 aliphatic or alicyclic alcohols. Specifically, n-hexanol, n-heptanol, isoheptyl alcohol, n
-Octanol, 2-ethylhexyl alcohol, methylcyclohexanol and the like. The above water-insoluble alcohols may be used alone or in combination of two or more.

The amount of these water-insoluble alcohols used is
As a component of the hydrogenation catalyst used in the hydrogenation reaction, a transition metal of Group 8 to Group 10 in a metal compound containing a Group 8 to Group 10 transition metal as a component and an organic aluminum compound 2-1 of the total number of moles with aluminum
It is preferably in the range of 000-fold mole, more preferably in the range of 5-500 mole. If the amount is less than 2 times, the effect of adding the water-insoluble alcohol cannot be obtained, and
Even if the molar amount exceeds 0 times, simply increasing the amount of the water-insoluble alcohol complicates the separation from the solvent.

In the present invention, the water-insoluble alcohol may be added to the reaction mixture in at least one step of treating the reaction mixture with an oxidizing agent, treating with an organic acid and / or an inorganic acid, and then washing with water. The term "add to the reaction mixture" means not only the case where the compound is directly added to the reaction mixture, but also the case where the compound is added to the reaction mixture indirectly by adding it to an oxidizing agent, an organic acid and / or an inorganic acid, or water for washing. Including cases. Since the water-insoluble alcohol is added in at least one stage of the above treatment, the addition is performed all at once or separately.

The hydrogenated diene polymer obtained by the production method of the present invention has a small amount of residual metal derived from the hydrogenation catalyst, is excellent in various physical properties such as hue and thermal stability, and is particularly safe in general industrial fields. It can also be suitably used for medical applications and food applications requiring properties.

[0029]

The present invention will now be described in more detail with reference to the following examples.
I will tell. Example 1 A number average molecular weight of 80,000,
Styrene-isoprene-styrene having a content of 30% by mass
700 g of the block copolymer is converted to 4000 g of cyclohexene.
Prepared in hexane beforehand in a solution dissolved in xane
Triisobutylaluminum (TIBA) and acetyla
Seton nickel complex salt [Ni (acac) _Two]
Hydrogenation catalyst [TIBA / Ni (acac)_Two= 3/1 (m
ol / mol)] is the isoprene unit of the block copolymer.
To the double bond based on the position, the N
i (acac)_Two0.1 mol% as Ni content
At a reaction temperature of 90 ° C. and a hydrogen pressure of 1 MPa.
And the iodine value of the block copolymer before and after the reaction.
The hydrogenation reaction was carried out until the determined hydrogenation rate reached 96%.
Was. Next, hydrogen peroxide is added to the reaction mixture after hydrogenation,
Total number of moles of Ni and Al contained in the used hydrogenation catalyst
And the mixture was stirred at 60 ° C. for 30 minutes.
Was. Next, n-octanol was included in the hydrogenation catalyst used.
5 times the molar amount of the total number of Ni and Al
And stirred at 60 ° C. for 5 minutes.
5 times the total number of moles of Ni and Al contained in
1500 g of distilled water in which an amount of citric acid is dissolved,
Minutes. Stop stirring and let stand for 30 minutes. Organic phase and aqueous phase
And separated into Add again 1500 g of distilled water to the organic phase,
Stir for 15 minutes, stop stirring and let stand for 30 minutes to leave organic and aqueous phases
And separated into The organic phase was concentrated under reduced pressure to remove hexane.
And dried at 100 ° C and 0.1 Pa for 8 hours.
And hydrogenated styrene-isoprene-styrene bromide
A block copolymer was obtained. The hydrogenated styrene-iso obtained
Residual aluminum for the prene-styrene block copolymer
The amounts of nickel and nickel were measured by an atomic absorption method. Conclusion
The results are shown in Table 1. Also, n- in the aqueous phase separated at the first time
Check octanol concentration by gas chromatography
The results are shown in Table 1.

Comparative Example 1 A hydrogenation reaction and a post-treatment were carried out in the same manner as in Example 1 except that methanol was used instead of n-octanol, and the hydrogenated styrene-isoprene-styrene block copolymer was obtained. The amounts of residual aluminum and nickel were measured by an atomic absorption method. Further, the methanol concentration in the aqueous phase separated for the first time was examined by gas chromatography. Table 1 shows the results. Comparative Example 2 A hydrogenation reaction and post-treatment were carried out in the same manner as in Example 1 except that n-octanol was not used, and residual aluminum in the obtained hydrogenated styrene-isoprene-styrene block copolymer and The nickel content was measured by an atomic absorption method. Table 1 shows the results.

[0031]

[Table 1]

[0032]

According to the present invention using a water-insoluble alcohol, the removal efficiency of metal components in the hydrogenation catalyst can be increased to the same level as in the case of using a water-soluble alcohol, and the use of a water-soluble alcohol can be improved. Since the amount of alcohol in the wastewater can be significantly reduced as compared with that of the first embodiment, the burden of wastewater treatment can be greatly reduced.

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Claims (1)

[Claims] 1. A diene polymer in a hydrocarbon solvent,
After hydrogenation using a hydrogenation catalyst comprising a metal compound having a transition metal of Group III to XV as a constituent component and an organoaluminum compound, the reaction mixture is treated with an oxidizing agent and treated with an organic acid and / or an inorganic acid. In a method for obtaining a hydrogenated diene polymer by solubilizing and removing the Group 8 to Group 10 transition metals and aluminum in the hydrogenation catalyst in the water washing solution, followed by washing with water, A method for producing a hydrogenated diene polymer, comprising adding a water-insoluble alcohol to a reaction mixture in at least one stage up to washing with water.