JPH0435481B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for stopping the polymerization of 1,3-butadiene using a 1,2-polymerization catalyst containing carbon disulfide. 1,3 using a cis-1,4 polymerization catalyst obtained from a cobalt compound and an organoaluminum compound
-Methods for stopping the polymerization of butadiene include alcohols such as methanol and ethanol, hydrochloric acid,
Polymerization termination methods using an inorganic acid such as sulfuric acid, a polymerization terminator such as monoethanolamine, ammonia, or hydrogen chloride are known. However, when 1,3-butadiene is polymerized using a 1,2 polymerization catalyst containing carbon disulfide and then the polymerization of 1,3-butadiene is terminated using the above polymerization terminator, these polymerization terminators By 1,
The double polymerization catalyst decomposes in a complicated manner, producing large amounts of sulfides such as ethyl mercaptan, hydrogen sulfide, and high-boiling sulfides, and these by-produced sulfides mix into the polymer, causing it to malodor. When the polymerization solvent is purified and recycled after termination of polymerization, these sulfides accumulate in the polymerization system, resulting in a problem in that the polymerization activity of the 1,2 polymerization catalyst decreases. The inventors have proposed 1,3 which does not have the aforementioned drawbacks.
- As a result of intensive research on a method for terminating polymerization of butadiene, the present invention was completed by using a specific compound used in the method of the present invention as a polymerization terminator. That is, this invention involves adding a phosphite to a polymerization reaction mixture obtained by polymerizing 1,3-butadiene using a 1,2 polymerization catalyst containing carbon disulfide in a polymerization solvent. , relates to a method for polymerizing 1,3-butadiene, which is characterized by bringing a dipolymerization catalyst into contact with a phosphite. Furthermore, the present invention includes the above method in a polymerization solvent solution of a diene (co)polymer soluble in boiling n-hexane, such as cis-1,4-polybutadiene, polyisoprene, or styrene-butadiene copolymer. 1,2
- Polymerize 1,3-butadiene using a polymerization catalyst, then add phosphite to
- A method for polymerizing 1,3-butadiene that terminates the polymerization is also included. Furthermore, 1,3-butadiene is first subjected to cis-1,4 polymerization by a known method, then the above-mentioned 1,2 polymerization catalyst is added to this polymerization solution to carry out 1,2-polymerization, and then 1,2-polymerization is carried out. A method in which polymerization is stopped by adding a phosphoric acid ester is also included. According to the method of the present invention, the amount of polymerization terminator used can be reduced, and the by-product of sulfide can be suppressed. In the method of this invention, a 1,2 polymerization catalyst containing carbon disulfide is used as a 1,3-butadiene polymerization catalyst. As such a 1,2 polymerization catalyst, a cobalt compound soluble in the polymerization solvent used, a general formula AlR ₃
A catalyst obtained from an organoaluminum compound and carbon disulfide is used. Cobalt compounds soluble in the polymerization solvent include cobalt β-diketone complexes such as cobalt () acetylacetonate and cobalt () acetylacetonate, and cobalt β-keto acids such as cobalt acetoacetic acid ethyl ester complex. Ester complexes, cobalt octoate, cobalt naphthenate, cobalt benzoate, etc. with 6 carbon atoms
Cobalt salts of the above organic carboxylic acids, cobalt halide complexes such as cobalt chloride pyridine complexes, cobalt chloride ethyl alcohol complexes, trisallyl cobalt, (1,3-butadiene) [1-(2-
Examples include methyl-3-butenyl)-π-allyl]cobalt. Examples of the organoaluminum compound represented by the general formula AlR ₃ include triethylaluminum,
Examples include trimethylaluminum, triisobutylaluminum, and tri-n-hexylaluminum. A part of the organoaluminum compound described above may be replaced with an organoaluminum halide described below. The amount of the 1,2 polymerization catalyst obtained from the cobalt compound soluble in the polymerization solvent, the organoaluminum compound represented by the general formula _AlR3 , and carbon disulfide depends on the type and combination of each catalyst component, and the polymerization conditions. Although it varies depending on the situation, the amount of cobalt compound is usually 0.005 mmol or more, especially 0.01 to 5 mmol, the organoaluminum compound is 0.1 mmol or more, especially 0.5 to 50 mmol, and carbon disulfide is 0.001 mmol or more per mole of 1,3-butadiene. , especially 0.01
Preferably it is ~10 mmol. The polymerization temperature for 1,2 polymerization using the above-mentioned 1,2 polymerization catalyst is preferably -20 to 80°C, particularly 5 to 50°C,
The polymerization pressure may be normal pressure or increased pressure, and the polymerization time is preferably in the range of 10 minutes to 10 hours. Furthermore, examples of the carbon disulfide-containing 1,2 polymerization catalyst used in the method of the present invention include catalysts obtained from cobalt compounds, organoaluminum halides, organolithium compounds, and carbon disulfide that are soluble in the polymerization solvent. . The organoaluminum halide described above has the general formula
It is _an organoaluminum compound represented by AlR _o Examples include alkyl aluminum halides such as diethylaluminum monochloride, diethylaluminium monobromide, diisobutylaluminum monochloride, ethylaluminum sesquichloride, and ethylaluminum dichloride. The organic lithium compound is an alkyl lithium compound, an aryl lithium compound, an alkylene dilithium compound, or an arylene dilithium compound, such as ethyl lithium, propyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium. and alkylurium compounds such as amyllithium. The amount of the 1,2 polymerization catalyst obtained from the cobalt compound, organoaluminium halide, organolithium compound, and carbon disulfide soluble in the polymerization solvent described above varies depending on the type and combination of each catalyst component and the polymerization conditions. However, with respect to the 1,3-butadiene used for polymerization, the cobalt compound soluble in the polymerization solvent is 0.0005 to 0.1 mol%, the organoaluminum halide is 0.01 to 1 mol%, and the organolithium compound is 0.01 to 1 mol%. Mol%, carbon disulfide 0.001
It is preferable that it is 1 mol%. Further, the amount of organoaluminum halide is preferably 10 to 500 mol, particularly 20 to 200 mol, per 1 mol of soluble cobalt compound, and the amount of organolithium compound is 5 to 200 mol, particularly 10 to 200 mol, per 1 mol of soluble cobalt compound.
The amount of carbon disulfide is preferably 0.1 to 500 mol, particularly 1 to 500 mol, per 1 mol of the soluble cobalt compound. Also, as an organoaluminum halide, the general formula
When using a compound represented by AlR _1.5 X _1.5 , for example, ethylaluminum sesquichloride,
The amount of the organolithium compound is preferably 0.5 mol or more per 1 mol of organoaluminum halide. Further, the amount of the organolithium compound is preferably 0.5 mol or more per 1 mol of the total amount of water present in the polymerization system. The polymerization temperature for 1,2 polymerization using the above-mentioned 1,2 polymerization catalyst is preferably -10 to 80°C, particularly 20 to 60°C, and the polymerization pressure may be normal pressure or higher. The carbon disulfide-containing 1,2 polymerization catalyst used in the method of the present invention is not limited to the above-mentioned two types, but may include known 1,2 polymerization catalysts such as Japanese Patent Publication No. 47-19893, Japanese Patent Publication No. 19893, 53-39917, Special Publication No. 56-18005, Special Publication No. 54-5436, Special Publication No. 56
−18128, Special Publication No. 18129, Special Publication No. 18129, Special Publication No. 18129
Any catalyst containing carbon disulfide and a cobalt compound as described in JP-A-18130 and JP-A-55-120611 can be used. Polymerization catalysts used in the method of this invention include aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, halides thereof, such as benzene, toluene, xylene, hexane, heptane, butane, butene, Examples include cyclohexane, cyclopentane, methylene chloride, and 1,2-dichloroethane. The polymerization solvent used in the method of the present invention is preferably one whose water concentration has been adjusted by dehydration to a water content of about 3 to 50 ppm. Furthermore, a polymerization solvent solution of a diene (co)polymer soluble in boiling n-hexane can also be used. Here, "polymerization solvent solution of a diene (co)polymer soluble in boiling n-hexane" refers to a boiling n-hexane solution containing the above-mentioned polymerization solvents as solutes, such as aromatic hydrocarbons and aliphatic hydrocarbons. - A solution of a diene (co)polymer soluble in hexane. Examples of diene-based (co)polymers soluble in boiling n-hexane include cis-1,4-polybutadiene, polyisoprene, and styrene-butadiene copolymers. As a method for preparing a polymerization solvent solution of these diene-based (co)polymers, there is, for example, a method of dissolving the diene-based (co)polymers in a polymerization solvent.
Alternatively, the diene-based (co)polymer can be prepared by solution polymerizing monomers such as 1,3-butadiene, isoprene, and styrene in the above polymerization solvent, and then stopping the polymerization using a known method. Also, furthermore, 1,
3-Butadiene is first treated using a known method, for example, a cis-
Cis-1,4 polymerization may be carried out by a method such as solution polymerization using a 1,4 polymerization catalyst, and this polymerization solution may be used without performing a polymerization termination operation. In the method of this invention, the concentration of 1,3-butadiene contained in the polymerization solvent is not particularly limited, but a concentration of 5 to 50% by weight relative to the polymerization solvent is generally preferred. In the method of this invention, a phosphite is used as a polymerization terminator. Examples of the phosphite include trimethylphosphite, triethylphosphite, triisopropylphosphite, tri-n-decylphosphite, triphenylphosphite, tricresylphosphite, tris(nonylphenyl)phosphite,
Examples include tris(propylphenyl) phosphite and tris(methylphenyl) phosphite. In particular, as a polymerization terminator, the general formula

Tris(alkylphenyl) represented by [Formula] (wherein, R is an alkyl group)
Phosphites are preferably used. In the method of this invention, 1,
The above-mentioned phosphite is added to the polymerization reaction mixture obtained by polymerizing 1,3-butadiene using a 2-polymerization catalyst, and the 1,2-polymerization catalyst and the phosphite are brought into contact with each other. The polymerization of 3-butadiene is stopped. In the method of this invention, it is necessary to use a phosphite as a polymerization terminator, and when a compound other than a phosphite is used as a polymerization terminator, it is difficult to terminate the polymerization of 1,3-butadiene. It is necessary to use a relatively large amount of a polymerization terminator, and the mono- and dipolymerization catalyst is complicatedly decomposed by the polymerization terminator, producing large amounts of various sulfides as by-products, resulting in a deterioration in the quality of the resulting polymer. The above-mentioned phosphorous acid ester may be used alone, or may be used in combination with water or a lower alcohol such as methanol or ethanol. In particular, a phosphite is added to a polymerization reaction mixture obtained by polymerizing 1,3-butadiene, the 1,2 polymerization catalyst and the phosphite are brought into contact, and then water or a lower alcohol is added. It is preferable to treat it by The amount of the phosphite used varies depending on the type and combination of each component of the 1,2 polymerization catalyst, but generally cobalt, which is soluble in the polymerization solvent, is a component of the 1,2 polymerization catalyst used. It is preferably 1 mol or more, particularly 1 to 20 mol, per mol of the compound. When a phosphite and water or a lower alcohol are used together, it is preferable that the phosphite is 0.2 mol or more and the water or the lower alcohol is 1 mol or more per mol of the organoaluminum compound. The temperature when stopping the polymerization of 1,3-butadiene using the above-mentioned phosphite is -10 to 80°C,
In particular, the temperature is preferably 5 to 60°C, and the time (average residence time) for bringing the 1,2 polymerization catalyst and phosphite into contact is preferably 0.1 to 60 minutes. The method of bringing the 1,2 polymerization catalyst into contact with the polymerization terminator may be a batch method or a continuous method. For example, after the polymerization reaction is completed, the polymerization reaction mixture is placed in a polymerization reactor (polymerization tank) equipped with a stirrer. A polymerization terminator may be added to the mixture, and the mixture may be stirred and mixed to bring the 1,2 polymerization catalyst and phosphite into contact with each other, or the polymerization reaction mixture may be introduced into a mixing tank (short stop tank) equipped with a stirrer. However, a polymerization terminator may be added to this polymerization reaction mixture, and the mixture may be stirred and mixed to bring the 1,2 polymerization catalyst and the phosphite into contact with each other. When stopping polymerization in a continuous manner, it is recommended to use two shot stop tanks in series, adding phosphite in the first tank and adding water or lower alcohol in the second tank. preferable. in this case,
The time for contacting the 1,2 polymerization catalyst and the phosphite in the first tank (average residence time) is 0.1
-60 minutes, particularly preferably 0.5-60 minutes, the temperature is preferably 5-60°C, and the time (average residence time) for treating the polymerization reaction mixture with water or lower alcohol in the second tank is 0.1-60 minutes. , especially 0.5
~60 minutes is preferred, and the temperature is preferably 5~60°C. After the polymerization of 1,3-butadiene has been terminated by the method described above, it can be carried out in a manner known per se, for example by adding a precipitating agent such as methanol to the polymerization reaction mixture, or by flashing (with or without blowing in water vapor). The solid content of the polymer is precipitated and separated and dried to obtain a diene rubber. The diene rubber is 1,2 polybutadiene having a melting point of 160 to 215°C, preferably 180 to 215°C, or preferably boiling n-hexane insoluble matter of 5 to 30°C.
It is a diene polymer containing % by weight. The melting point of this boiling n-hexane insoluble matter is preferably 180 to
The temperature is 215℃. The 1,2 structure content of the 1,2-polybutadiene and boiling n-hexane insoluble components is preferably 80% or more. It is preferable to mix an anti-aging agent into the diene rubber. The mixture containing unreacted 1,3-butadiene, polymerization solvent, and carbon disulfide (usually referred to as recovery solvent), which remains after separating the solid diene rubber from the polymerization reaction mixture, is washed with water (alkaline water washing). The 1,3-butadiene, polymerization solvent, and carbon disulfide can be recovered by distillation, etc., and recycled for use. Examples and comparative examples are shown below. In the following description, parts indicate parts by weight. In each of the following examples, the contents of carbon disulfide, ethyl mercaptan, and hydrogen sulfide in the polymerization reaction mixture were determined using gas chromatography equipped with a flame photometric detector filled with Chromosolve 102. Example 1 The air was replaced with nitrogen, and dried 1,
A benzene solution of 1,3-butadiene (moisture 1.0
3.5 mmol of triethylaluminum, 0.043 mmol of cobalt acetylacetonate (), and 0.13 mmol of carbon disulfide were added sequentially to this 1,3-butadiene benzene solution while keeping the liquid temperature at 40°C. The mixture was stirred and mixed to perform 1,2 polymerization of 1,3-butadiene. After polymerization for 20 seconds, a solution of 0.3 mmol of tris(nonylphenyl) phosphite (TNP) dissolved in 10 ml of benzene was added, and the solution was stirred and mixed at 40° C. for 3 minutes to stop the polymerization. While stirring this solution, 5.0 ml of solution was withdrawn every time a predetermined period of time elapsed.
The polymer was separated and recovered by pouring it into 50 ml of methanol, followed by vacuum drying to obtain 1,2-polybutadiene. The results are summarized in Table 1. Comparative Example 1 The same procedure as in Example 1 was carried out except that the solution of tris(nonylphenyl)phosphite dissolved in benzene was not added. The results are summarized in Table 1.

[Table] Examples 2 to 4 A Teflon-coated stirrer piece was placed in an Erlenmeyer flask with an internal volume of 500 ml, a three-way pot was attached, and the flask was purged with nitrogen. 10 in this flask
Add 220 ml of a benzene solution containing 1,3-butadiene at 1,3% by weight, and add 1 ml of water to the benzene solution of 1,3-butadiene while keeping the liquid temperature at 40°C.
After adding carbon disulfide at a rate of 36 mg (the same applies hereinafter) and mixing uniformly, add 0.075 mmol of carbon disulfide/
, 0.53 diethylaluminum monochloride
g/, dilaurylthiodipropionate (TPL) 0.135g/, 1,5-cyclooctadiene (COD) 1.50g/, triethylaluminum 0.50g/, cobalt octoate
Added sequentially at a rate of 0.05 mmol/10 at 25°C.
The solution was stirred and mixed for seconds to polymerize 1,3-butadiene. Next, a compound of the type shown in Table 2 (added as a dehydrated benzene solution) was added to the polymerization reaction mixture as a polymerization terminator, and the mixture was further stirred and mixed for 30 minutes, and then the mixture was poured into a large amount of methanol. After separating and recovering the polymer, vacuum drying
1,2-polybutadiene was obtained. The results are summarized in Table 2. Comparative Examples 2 to 4 Except for adding a compound of the type shown in Table 2 as a polymerization terminator (added as a dehydrated benzene solution),
It was carried out in the same manner as in Example 2. Summary of the results in the second
Shown in the table.

[Table] The above results show that phosphite has an excellent effect in stopping the polymerization of 1,3-butadiene by a 1,2 polymerization catalyst containing carbon disulfide. Examples 5 to 8 Air was replaced with nitrogen, and dried 1,3 was placed in a separable flask with an internal volume of 2 equipped with a thermometer, a stirring rod, a nitrogen gas introduction pipe, and a polymerization liquid extraction device.
- Add a solution of 1,3-butadiene (containing 2 mmol of water) prepared by dissolving 85 g of butadiene in 860 ml of dehydrated benzene, and add carbon disulfide while keeping the temperature of the solution at 40°C.
0.300 mmol was added. This solution contains 4.4 mmol of diethylaluminum monochloride, COD14
mmol, 0.24 mmol of TPL, and 0.014 mmol of cobalt octoate were sequentially added, and the solution was stirred and mixed at 40° C. for 30 minutes to cis-polymerize 1,3-butadiene.
Immediately thereafter, 5.3 mmol of triethylaluminum and 0.02 mmol of cobalt octoate were added, and the solution was stirred and mixed at 40° C. for 30 minutes to perform 1,2 polymerization of 1,3-butadiene. After polymerization, polymerization solution 5.0
ml was taken out, and a solution of the compound shown in Table 3 dissolved in 5 ml of benzene as a polymerization terminator was added to the taken out polymerization liquid, and the solution was cooled to about 10°C and mixed for 5 minutes to stop the polymerization. 0.5 ml of methanol was added and mixed to obtain a polymerization reaction mixture in which polymerization was terminated. This mixed solution was diluted five times with dry benzene, and the sulfides in the polymerization solution were analyzed. Further, the polymerization reaction mixture was poured into 50 ml of methanol, the polymer was separated and recovered, and then vacuum dried to obtain a reinforced polybutadiene rubber. The results are summarized in Table 3. Comparative Example 5 The same procedure as in Example 5 was carried out, except that a compound of the kind and amount shown in Table 3 (added as a dehydrated benzene solution) was added as a polymerization terminator. The results are summarized in Table 3.

[Table] The reinforced polybutadiene rubbers obtained in Examples 5 to 8 had a boiling n-hexane insoluble content of 12 to 13.5% by weight.
, and the reduced viscosity (η _SP /C) of boiling n-hexane insoluble matter (135°C, tetralin solution) is
3.4, the 1,2 structure content is 92 to 95%,
Intrinsic viscosity of boiling n-hexane soluble fraction [η] (30℃,
toluene solution) was 2.3 in both cases. Also,
The polymerization yield of all polymers was 50 to 55%. Example 9 85 g of dried 1,3-butadiene was dissolved in 860 ml of dehydrated benzene in a separable flask with an inner volume of 2 and equipped with a thermometer, a stirring rod, and a nitrogen gas inlet tube, with the air replaced with nitrogen. Add a benzene solution of 3-butadiene (containing 1.0 mmol of water),
While keeping the liquid temperature at 40°C, 4.6 mmol of COD, 4.0 mmol of diethylaluminium monochloride, and 0.043 mmol of cobalt octoate were added to this benzene solution of 1,3-butadiene with stirring, and then the mixture was heated to 40°C with continued stirring. ℃
1,3-butadiene was subjected to cis-1,4 polymerization for 10 minutes. Polymer has 96% cis-1,4 structure content
Intrinsic viscosity [η] (30℃, toluene)
was 2.4. Immediately after cis-1,4 polymerization, n
-butyllithium 2.0 mmol and carbon disulfide
After adding 0.40 mmol, 1,3-butadiene was 1,2-polymerized at 40° C. for 8 minutes while stirring. Tris(nonylphenyl)phosphite is added to this system.
After adding 10 ml of a dry benzene solution containing 0.2 mmol and continuing stirring for 3 minutes, 10 ml of methanol containing 0.5 g of BHT was added. This mixed solution was diluted five times with dry benzene, and the sulfides in the polymerization solution were analyzed.
Further, the mixed solution was poured into a large amount of methanol to separate and recover the polymer, which was then vacuum dried to obtain a reinforced polybutadiene rubber. The results are summarized in Table 4. Comparative Example 6 The same procedure as Example 9 was carried out except that tris(nonylphenyl)phosphite was not added. The results are summarized in Table 4.

【table】

Claims (1)

[Claims] 1. 1,2 containing carbon disulfide in a polymerization solvent
Adding a phosphorous ester to a polymerization reaction mixture obtained by polymerizing 1,3-butadiene using a polymerization catalyst, and bringing the 1,2 polymerization catalyst and the phosphorous ester into contact to terminate the polymerization, 1 , 3-butadiene polymerization method. 2 (a) 1,2-polymerization of 1,3-butadiene using a 1,2 polymerization catalyst containing carbon disulfide in a polymerization solvent solution of a diene polymer soluble in boiling n-hexane. (b) A method for polymerizing 1,3-butadiene, which comprises adding a phosphorous ester to the obtained polymerization reaction mixture, bringing the 1,2 polymerization catalyst and the phosphorous ester into contact, and stopping the polymerization. 3 (a) cis-1,4 polymerization of 1,3-butadiene in a polymerization catalyst, and then (b) cis-1,4 polymerization of 1,3-butadiene using a 1,2 polymerization catalyst containing carbon disulfide in the polymerization solvent solution. , 3-butadiene, (c) adding a phosphorous ester to the obtained polymerization reaction mixture and bringing the 1,2 polymerization catalyst and the phosphorous ester into contact to terminate the polymerization, 1,3- Butadiene polymerization method. 4 Phosphite has the general formula, (However, R is an alkyl group.) Any one of claims 1 to 3 is a tris(alkylphenyl)phosphite represented by
The method described in section.