JPS62170B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing cis-1,4 polybutadiene.

Conventionally, as a method for producing cis-1,4 polybutadiene, a method is known in which 1,3-butadiene is polymerized in an inert organic solvent containing water using a catalyst obtained from a halogen-containing organoaluminum compound and a cobalt compound. .

In this conventionally known method, it is essential to contain water in the solvent in order to improve the catalytic activity, and therefore polybutadiene with a high content of cis-1,4 structure can be obtained, but on the other hand, Polybutadiene contains gel and the polymer tends to adhere to the stirring blades and inner walls of the polymerization tank, which limits the uses of this polybutadiene and has the disadvantage that polymerization cannot be continued for a long time.

Therefore, in order to suppress gel formation and polymer adhesion in the polymerization tank, methods have been proposed in which amines, hydrazine, hydroquinone, etc. are added to the polymerization system as antigelation agents. However, it is not possible to prevent the formation of gel and the adhesion of the polymer into the polymerization tank, and the activity of the catalyst is reduced, which is not satisfactory.

The inventors of this application conducted research with the aim of polymerizing 1,3-butadiene in an inert organic solvent using the catalyst and suppressing the formation of gel and the adhesion of the polymer into the polymerization tank. completed this invention.

That is, this invention provides 1,3-
In a method for cis-1,4 polymerization of butadiene, (a) 1,3-butadiene and an inert organic solvent are mixed, (b) water in the obtained inert organic solvent solution of 1,3-butadiene is (c) Add a halogen-containing organoaluminum compound to the obtained solution, and heat the obtained mixture in the absence of a cobalt compound at a temperature of 10 to 50°C for 2 minutes to 2 hours. After aging, (d) a cobalt compound is added and the resulting solution is stirred and mixed to polymerize 1,3-butadiene.

In the method of this invention, in the first step (a), 1,3-butadiene and an inert organic solvent are preferably added to the 1,3-butadiene and the inert organic solvent based on the total amount of 1,3-butadiene and the inert organic solvent. They are mixed so that the proportion thereof is 3% by weight or more, particularly 3 to 40% by weight.

Then, in step (b), the concentration of water in the inert organic solvent solution of 1,3-butadiene obtained as described above is adjusted. Water is preferably contained in the solution 1 at a concentration of 0.5 to 5 mmol. Methods known per se can be applied to adjust the water concentration.

In the method of this invention, after adjusting the water concentration in the inert organic solvent solution of 1,3-butadiene, in step (c), a halogen-containing organoaluminum compound is added to the obtained solution, and The resulting mixed solution is aged for 2 minutes to 2 hours in the presence of a cobalt compound. In this invention, it is necessary to age the mixture to which the halogen-containing organoaluminum compound is added in the absence of a cobalt compound, thereby improving the activity of the catalyst and forming a gelatin during polymerization. can suppress the generation of
Therefore, it is possible to suppress the adhesion of polymer into the polymerization tank, and it is also possible to extend the continuous polymerization operation time. The effect of the above-mentioned aging is remarkable when moisture is not added to the solution after aging.
Even if a mixed solution containing no 1,3-butadiene is aged, or a mixed solution containing a cobalt compound instead of a halogen-containing organoaluminum compound is aged, the effect of aging is small, and the amount of polymer in the polymerization tank is small. adhesion cannot be suppressed.

The time to ripen a mixture of 1,3-butadiene in an inert organic solvent solution with adjusted water concentration and a halogen-containing organoaluminum compound added is as follows:
The aging time is 2 minutes to 2 hours, and the ripening temperature is preferably 10 to 80°C, particularly 10 to 50°C. If the aging time is less than 2 minutes, the effect of aging will be reduced.

The inert organic solvent is not particularly limited as long as it dissolves the cis-1,4 polybutadiene formed and does not adversely affect the activity of the catalyst, but aromatic solvents such as benzene, toluene, and xylene may be used. Hydrocarbon solvents include hydrocarbons, aliphatic hydrocarbons such as n-hexane and n-heptane, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane.

Examples of the halogen-containing organoaluminum compound which is a component of the catalyst used in the method of the present invention include dialkylaluminum halides such as diethylaluminum monochloride and diisobutylaluminum monochloride. The amount of the halogen-containing organoaluminum compound used is preferably 0.1 mmol or more, particularly 0.5 to 50 mmol, per mole of the total amount of 1,3-butadiene. The amount of 1,3-butadiene used for aging the halogen-containing organoaluminum compound may be the entire amount of 1,3-butadiene used in the polymerization, or may be a part of the 1,3-butadiene used in the polymerization. Good too. After aging the halogen-containing organoaluminum compound, additional 1,3-
When butadiene is added, it is necessary to use 1,3-butadiene that does not substantially contain water.

In the method of this invention, an inert organic solvent solution containing 1,3-butadiene and water is
After aging the mixed solution to which the halogen-containing organoaluminum compound has been added, preferably after cooling the obtained aged solution to 10°C or below to adjust the temperature, in step (d), one of the other components of the catalyst is added. Add a cobalt compound and stir and mix the resulting solution.
Polymerize 3-butadiene.

The cobalt compound which is a component of the catalyst used in the method of this invention may be of any type as long as it is soluble in the hydrocarbon solvent used. For example, such cobalt compounds include cobalt() acetylacetonate, cobalt()
cobalt β-diketone complexes such as acetylacetonate, cobalt β-keto acid ester complexes such as cobalt acetoacetate ethyl ester complex;
cobalt octoate, cobalt naphthenate,
Examples include cobalt salts of organic carboxylic acids having 6 or more carbon atoms such as cobalt benzoate, cobalt halide complexes such as cobalt chloride pyridine complexes, and cobalt chloride ethyl alcohol complexes.

The amount of cobalt compound used is 0.001 mmol or more, especially 0.005 mmol per 1 mol of 1,3-butadiene.
Preferably, it is millimole or more.

Further, the molar ratio (Al/Co) of the halogen-containing organoaluminum compound to the cobalt compound is preferably 5 or more, particularly 15 or more.

In the method of this invention, the polymerization temperature is 5 to 80°C;
In particular, a temperature of 20 to 70°C is preferred, the polymerization pressure may be normal pressure or higher, and the polymerization time (average residence time) is 10°C.
A range of minutes to 10 hours is preferred. Further, polymerization is carried out by stirring and mixing the solution in a polymerization reactor (also referred to as a polymerization tank). As a polymerization reactor used for polymerization,
A polymerization reactor equipped with a high viscosity liquid stirring device, for example, the device described in Japanese Patent Publication No. 40-2645, can be used.

In the method of the invention, known molecular weight regulators can be used during polymerization, for example non-conjugated dienes such as cyclooctadiene and allene, or α-olefins such as ethylene, propylene and butene-1. In addition, a known gel inhibitor can be used to further suppress the formation of gel during polymerization. The molecular weight regulator may be added in any of the steps (a) to (d) above, and the antigel agent may also be added in each step.

According to the method of the present invention, it is possible to suppress the adhesion of the polymer into the polymerization tank during the polymerization of 1,3-butadiene, so that the polymerization reaction can be continued for a long time.

Further, according to the method of this invention, cis-1,4
Polybutadiene can be produced in high yield.

After completion of the polymerization reaction, known methods can be applied to obtain cis-1,4 polybutadiene. For example, after the polymerization reaction is completed, the polymerization solution is supplied to a polymerization stop tank, and a large amount of alcohol such as methanol or ethanol, or a polar solvent such as water that reacts with the dialkyl aluminum monohalide is added to the polymerization solution, or A method of adding a polymerization solution to a large amount of a polar solvent, a method of adding a small amount of a polar solvent to a polymerization solution including inorganic acids such as hydrochloric acid and sulfuric acid, organic acids such as acetic acid and benzoic acid, monoethanolamine and ammonia, and hydrogen chloride. After stopping the polymerization of 1,3-butadiene by methods known per se, such as by introducing a gas into the polymerization solution, a precipitating agent such as methanol is added or flashing (with or without the introduction of water vapor) The solvent is removed by evaporation), and the polymer is precipitated and separated and dried to obtain cis-1,4 polybutadiene. An anti-aging agent can be added to cis-1,4 polybutadiene by adding the anti-aging agent to a polymerization solution after stopping the polymerization of 1,3-butadiene or to a slurry of cis-1,4 polybutadiene. It is preferable to mix them. As anti-aging agents, 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol (BHT), styrenated phenol,
4,4'-thiobis(6-tert-butyl-3-methylphenol), 1,1'-bis-(4-hydroxyphenyl)cyclohexane, 1-oxy-3-methyl-4-isopropylbenzene, n- Octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionate, 2,5-di-tert-amylhydroquinone, 2,5-di-tert-butylhydroquinone, 2,2'-methylenebis- (4-methyl-6-tert-butylphenol), tris-(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, butylated hydroxyanisole,
4,4'-butylidenebis-(3-methyl-6-tert-butylphenol), nickel dibutyl dithiocarbamate, nickel isopropyl xanthate, tri(nonylated phenyl) phosphite (TNP), dilauryl thio dipropionate, Examples include distearylthio dipropionate. Anti-aging agents may be used alone or in combination of two or more. The above-mentioned anti-aging agent is used in total amount based on polybutadiene.
It is preferable that the content is 0.001 to 5% by weight.

By the method of the present invention, cis-1, which has a high content of cis-1,4 structure and does not substantially contain gel components,
4 polybutadiene can be obtained.

Next, Examples and Comparative Examples will be shown.

Example 1 A benzene solution (containing 1.8 mmol/water) containing 1,3-butadiene at a concentration of 24% by weight was fed into the stainless steel aging tank with a stirrer as described in Content 2 at 30 times per hour, and diethylaluminum monochloride was fed into the tank. The mixture was mixed at 112.5 mmol per hour and aged at 30°C for 4 minutes (average residence time). The obtained aged liquid was cooled to -3°C and fed into a stainless steel polymerization tank with a ribbon-type stirrer with a content of 15% per hour, and 0.40 mmol of cobalt octoate and 1,5-cyclooctadiene were added per hour. 94.3 mmol and TPL
(dilauryl-3,3'-thiopropionate) was mixed in at 6.0 mmol per hour, and the average residence time was 30 at 30°C.
Polymerization was carried out for 36 hours. The obtained polymerization product liquid was supplied to a mixing tank equipped with a stirrer, and 1 PHR of 2,6-di-tert-butyl 4-methylphenol (BHT) was added to the rubber, and a small amount of methanol was added to the mixture to induce polymerization. After the reaction was stopped, unreacted 1,3-butadiene and the solvent were removed by evaporation and vacuum-dried at room temperature to obtain 69.1 kg of cis-1,4 polybutadiene.

This polybutadiene has an intrinsic viscosity [η] of
4.2, the microstructure was 97.6% cis-1,4 structure, 1.7% trans-1,4 structure, and 0.7% 1,2 structure.

Further, when a predetermined amount of this polybutadiene was dissolved in benzene and the gel content was measured using a 200-mesh wire mesh, the gel content was 0.04%.

After the polymerization reaction was completed, the polymer (including gel) adhering to the stirring blades and inner walls of the polymerization tank was scraped off and vacuum dried at room temperature, and the amount of adhering polymer (including gel) was 55 g.

Example 2 Add a benzene solution to the aging tank with content 15,
68.9 kg of cis-1,4 polybutadiene was obtained by carrying out the same procedure as in Example 1 except for aging at 30° C. for 30 minutes (average residence time).

This polybutadiene has an intrinsic viscosity [η] of
4.3, and the gel content was 0.02%.

The amount of polymer (including gel) deposited in the polymerization tank after 36 hours of polymerization reaction was 35 g.

Example 3 Aging by changing the aging temperature from 30℃ to 10℃,
cis-
67.5 kg of 1,4 polybutadiene was obtained.

This polybutadiene has an intrinsic viscosity [η] of
4.2, and the gel content was 0.03%.

The amount of polymer (including gel) deposited in the polymerization tank after 36 hours of polymerization reaction was 38 g.

Comparative Example 1 The same procedure as in Example 1 was carried out except that a mixed solution in which cobalt octoate was added instead of diethylaluminum monochloride was aged, and diethylaluminum monochloride was directly added to the polymerization tank for polymerization. , 4 polybutadiene (58.8 kg) was obtained.

This polybutadiene has an intrinsic viscosity [η] of
4.2, the gel content was 0.60%.

The amount of polymer (including gel) deposited in the polymerization tank after 36 hours of polymerization reaction was 315 g.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the aging conditions were changed to 30°C for 50 seconds (average residence time), and cis-1,
68.5 kg of 4-polybutadiene was obtained.

This polybutadiene has an intrinsic viscosity [η] of
4.3, and the gel content was 0.52%.

The amount of polymer (including gel content) deposited in the polymerization tank after 36 hours of polymerization reaction was 240 g.

Claims (1)

[Claims] 1. In an inert organic solvent, in the presence of a catalyst obtained from a halogen-containing organoaluminium compound and a cobalt compound, 1,3-butadiene is cis-
In the method of 1,4 polymerization, (a) 1,3-butadiene and an inert organic solvent are mixed, (b) the concentration of water in the obtained inert organic solvent solution of 1,3-butadiene is adjusted. (c) adding a halogen-containing organoaluminium compound to the obtained solution, aging the obtained mixture in the absence of a cobalt compound at a temperature of 10 to 50°C for 2 minutes to 2 hours; (d) A method for producing cis-1,4 polybutadiene, which comprises adding a cobalt compound and stirring and mixing the resulting solution to polymerize 1,3-butadiene. 2. The manufacturing method according to claim 1, wherein the concentration of 1,3-butadiene in the inert organic solvent solution is 3% by weight or more. 3. The manufacturing method according to claim 1, wherein the concentration of water in the solution of 1,3-butadiene in an inert organic solvent is 0.5 to 5 mmol/. 4. The production method according to claim 1, wherein a molecular weight regulator is added to the solution of 1,3-butadiene in an inert organic solvent or to the solution in which it is polymerized.