JPH0952912A - Production of cis-1, 4-polybutadiene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject compound, excellent in high stereoregular polymerizability, useful for a synthetic rubber, etc., by smooth continuous operation in high yield and in high catalytic efficiency, by introducing a polymer solution preliminarily polymerized under a specific condition to a continuous polymerizing tank. SOLUTION: When continuously polymerizing 1, 3-butadiene in an inert organic solvent by using a water-organoaluminum chloride (e. g. diethylaluminum monochloride, etc.)-soluble cobalt compound (e. g. cobalt octoate, etc.)as a catalytic component, the preliminary polymerization is carried out at-20 to 20 deg.C under conditions obtainable 500-30,000g cis-1, 4-polybutadiene based on 1g cobalt atom. The preliminarily polymerized polymer solution is introduced to a continuous polymerizing tank and 1, 3-butadiene is continuously polymerized in the ratio of >=80,000g based on 1g of cobalt atom in the polymerization temperature range of above 20 deg.C to 100 deg.C.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a continuous process for producing cis-1,4-polybutadiene. More specifically, the present invention relates to an improvement in a continuous production method of cis-1,4-polybutadiene having excellent long-term continuous operability and high catalytic activity.

[0002]

2. Description of the Related Art Conventionally, as a continuous production method of cis-1,4-polybutadiene, after adjusting the water concentration of a mixed solution of 1,3-butadiene and an inert organic solvent and adding an organoaluminum chloride thereto, The method of continuously polymerizing 1,3-butadiene by adding a soluble cobalt compound is well known.

1,3-Butadiene and an inert organic solvent are mixed, the concentration of water in the obtained 1,3-butadiene inert organic solution is adjusted, and organoaluminum chloride is added to the resulting solution. A method of continuously producing cis-1,4-polybutadiene by aging the obtained mixed solution in the absence of a soluble cobalt compound and then continuously polymerizing 1,3-butadiene by adding a soluble cobalt compound No. 795,860.

Further, in Japanese Examined Patent Publication No. 47-13052, the concentration of the soluble cobalt compound when introduced into the polymerization tank is at least equal to the concentration of the cobalt compound in the reaction tank,
A continuous polymerization method is described in which the concentration of the cobalt compound in the reaction vessel is less than 4 times and introduced. Further, the continuous polymerization method described in U.S. Pat. No. 3,066,127 uses a reaction vessel provided with a separate inlet for the catalyst produced in advance. Japanese Patent Publication No. 47-19894 describes that it is difficult to adjust the preliminary reaction of the catalyst component.

[0005]

However, these continuous production methods of cis-1,4-polybutadiene can obtain polybutadiene having a high cis-1,4 structure content, but when continuously operated for a long time, cis-1,4-polybutadiene can be obtained. -1,4-polybutadiene contains gel swollen insoluble in organic solvent,
It easily adheres to the stirring blades and inner walls of the polymerization tank, which limits the use of this cis-1,4-polybutadiene and limits the flow in the system, resulting in a rapid decrease in reaction heat removal performance and long-term operation. It has the drawback of not being able to continue. The present invention has been made to solve the above problems, and in a method of continuously polymerizing 1,3-butadiene in an inert organic solvent using water-organoaluminum chloride-soluble cobalt compound as a catalyst component. ,
High cis-1,4 structure content, low gel content,
It is an object of the present invention to provide a method for producing cis-1,4-polybutadiene that can be continuously operated for a long time.

[0006]

The present invention provides a method for continuously polymerizing 1,3-butadiene using a water-organoaluminum chloride-soluble cobalt compound as a catalyst component in an inert organic solvent, comprising the steps of (a) preliminary Polymerization temperature is -20
〜500 ℃ per 1g of cobalt atom in the temperature range of 〜20 ℃
Preliminary polymerization is carried out under the condition that 30,000 g of cis-1,4-polybutadiene is obtained, and (b) the preliminarily polymerized polymerization liquid is introduced into a continuous polymerization tank so that the polymerization temperature is from 20 ° C to 100 ° C.
The present invention relates to a process for producing cis-1,4-polybutadiene, which comprises continuously polymerizing 1,3-butadiene in an amount of 80,000 g or more per 1 g of cobalt atom in a temperature range up to ° C.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION First, one aspect of the continuous production method of the present invention will be described. With respect to 1,3-butadiene and the inert organic solvent, the ratio of 1,3-butadiene to the total amount of 1,3-butadiene and the inert organic solvent is preferably 10% by weight or more, particularly 10 to 60% by weight. To mix.
When it is 60% by weight or more, it is difficult to control the continuous production method, and when it is 10% by weight or less, the efficiency of the continuous production method of cis-1,4-polybutadiene decreases, which is not preferable.

The inert organic solvent is not particularly limited as long as it is an organic solvent which dissolves the cis-1,4-polybutadiene to be produced and does not adversely affect the activity of the catalyst, but is not limited to benzene, toluene, xylene, chlorobenzene and the like. And aromatic hydrocarbons such as n-hexane and n-heptane, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. Further, a hydrocarbon containing a C ₄ fraction as a main component such as butene-1, cis-2-butene, trans-2-butene, and n-butane can also be used.

Then, the concentration of water in the mixed solution obtained by mixing the obtained 1,3-butadiene and an inert organic solvent is adjusted. The water content in the mixed solution is preferably 0.1 to 1.0 mol, and particularly preferably 0.2 to 1.0 mol, per 1 mol of organoaluminum chloride.
Outside this range, the catalytic activity will decrease, and cis-1,
4.Structural content is reduced, molecular weight is abnormally reduced or increased, gel at the time of polymerization cannot be suppressed, and therefore gel is attached to the polymerization tank, etc., and continuous polymerization time is further extended. It is not preferable because it cannot be done. A known method can be applied to the method for controlling the concentration of water.

Organoaluminum chloride is added to the solution obtained by adjusting the concentration of water in the mixed solution of 1,3-butadiene and an inert organic solvent. Specific examples of the organic aluminum chloride, diethyl aluminum monochloride, diisobutyl aluminum monochloride,
Examples thereof include dialkylaluminum monochlorides such as dicyclohexylaluminum monochloride and diphenylaluminum monochloride. The amount of organoaluminum chloride used is 0.1 mol or more, particularly 0.5 to 50, per 1 mol of the total amount of 1,3-butadiene.
Mmol is preferred.

To the solution obtained by adjusting the concentration of water in the mixture of 1,3-butadiene and the inert organic solvent, organoaluminum chloride is added and the temperature is within the range of -10 to 50 ° C for 5 minutes to. Premix (age) for 60 minutes. By this operation, the premixed liquid is aged and stabilized. If the premixing time is too long or too short, the aging becomes insufficient to lower the productivity, and the gel formation increases, so that the above range is preferable. The amount of 1,3-butadiene used during the premixing may be the total amount of 1,3-butadiene used for the polymerization or a part of the 1,3-butadiene used for the polymerization. For 1,3-butadiene added after the premixing, it is necessary to use 1,3-butadiene that does not substantially contain water.

A soluble cobalt compound is added to the premixed mixed solution. Any soluble cobalt compound may be used as long as it is soluble in an organic solvent, for example, cobalt (I
I) β-diketone complexes of cobalt such as acetylacetonate and cobalt (III) acetylacetonate, β-cobalt such as cobalt acetoacetic acid ethyl ester complex
-Ceto acid ester complex, cobalt octoate, cobalt naphthenate, cobalt benzoate, etc. having 6 carbon atoms
Examples thereof include cobalt salts of organic carboxylic acids, cobalt chloride pyridine complexes, and cobalt halide complexes such as cobalt chloride ethyl alcohol complexes. The amount of soluble cobalt compound used is 1 of 1,3-butadiene.
It is preferably 0.001 mmol or more, and particularly preferably 0.005 mmol or more per mol. The molar ratio (Al / Co) of the organoaluminum chloride to the soluble cobalt compound is preferably 10 or more, particularly 50 or more.

1,3-Butadiene and an inert organic solvent are mixed, the water concentration in the obtained mixed solution is adjusted, and organoaluminum chloride is added to the obtained mixed solution.
After aging the obtained mixed solution, a soluble cobalt compound is added to continuously polymerize 1,3-butadiene, and 500 to 30,000 per 1 g of cobalt atom is used.
0 g, preferably 1,000-20,000 g cis-
It is necessary to pre-polymerize 1,3-butadiene under the condition that 1,4-polybutadiene is obtained. The prepolymerization is preferably carried out in an inert organic solvent under mild conditions. For example, the mild prepolymerization temperature is in the temperature range of -20 to 20 ° C.
Min to 60 min, preferably in the temperature range of -10 to 20 ° C,
Prepolymerize for 5 to 30 minutes. If the prepolymerization time is too long, the catalyst activity will increase and continuous operability will be difficult. On the contrary, if the activity of the catalyst is insufficient, gelation will occur and the productivity will decrease, so the above range is preferred. If the prepolymerization temperature is too high or too low, it becomes difficult to control the reaction or the activation of the catalyst becomes insufficient, which causes the formation of gel, so that the above temperature range is preferable.

The preliminarily polymerized polymerization solution is introduced into a continuous polymerization tank and the polymerization temperature exceeds 20 ° C to 100 ° C, preferably 30 to 100 ° C, more preferably 40 to 100 ° C.
In the temperature range up to 1,3-butadiene is continuously polymerized with cis-1,4-polymer of 80,000 g or more per 1 g of cobalt atom, preferably 100,000 to 400,000 g per 1 g of cobalt atom. Polymerization time (average residence time)
Is preferably in the range of 10 minutes to 10 hours. The continuous polymerization tank is performed by connecting one tank or two or more tanks. Polymerization is performed by stirring and mixing the solution in a polymerization tank (polymerizer). As the polymerization tank used for the polymerization, a polymerization tank equipped with a high-viscosity liquid stirring device, for example, the device described in JP-B-40-2645 can be used.

In the present invention, known molecular weight regulators, for example, non-conjugated dienes such as cyclooctadiene and allene, or α-olefins such as ethylene, propylene and butene-1 can be used during the polymerization. Further, a known gelation inhibitor can be used in order to further suppress the formation of gel during polymerization.

After the polymerization reaction reaches a predetermined polymerization rate, a known antioxidant can be added according to a conventional method. Typical anti-aging agents are phenolic 2,6-di-
t-Butyl-p-cresol (BHT), phosphorus-based trinonylphenyl phosphite (TNP), sulfur-based dilauryl-3,3'-thiodipropionate (TPL)
These may be used alone or in combination of two or more, and the addition amount of the antioxidant is 0.001 to 5 parts by weight with respect to 100 parts by weight of cis-1,4-polybutadiene. Then, a polymerization terminator is added to the polymerization system to terminate. For example, after the completion of the polymerization reaction, supply to a polymerization termination tank, a method of adding a large amount of a polar solvent such as methanol, alcohol such as ethanol, water, etc. to this polymerization solution, inorganic acids such as hydrochloric acid, sulfuric acid, acetic acid, benzoic acid, etc. A method known per se, such as a method of introducing the organic acid or hydrogen chloride gas into the polymerization solution. Then, the cis-1,4-polybutadiene produced according to a usual method is separated, washed and dried. The cis-1,4-polybutadiene thus obtained was cis-1,
4-structure content is generally 97% or more, Mooney viscosity (M
L _{1 + 4} , 100 ° C.) 20 to 80 or more, and has a linear shape containing substantially no gel component.

By continuously operating the method according to the present invention,
The operability of the catalyst component is excellent, and cis-1,4-polybutadiene can be continuously produced for a long time with high catalytic efficiency and industrially advantageously. Especially, since the prepolymerization is carried out at a low temperature,
Having high stereoregularity and excellent polymerization operability, there is no gel insoluble in the solvent, neither sticking to the inner wall or stirring blades in the polymerization tank, or other portions where stirring is slow,
Continuous production can be industrially advantageous with a high conversion rate.

The cis-1,4-polybutadiene obtained according to the present invention is blended alone or in a blend with another synthetic rubber or natural rubber, oil extended with a process oil if necessary, and then filled with carbon black or the like. Agent, vulcanizing agent,
It is used for rubber applications such as tires, hoses, belts and various other industrial products that require mechanical properties and abrasion resistance after vulcanization by adding a vulcanization accelerator and other usual compounding agents. It can also be used as a modifier for plastics.

[0019]

EXAMPLES The present invention will be specifically described below based on examples, but the objects of the present invention are not limited thereto.

[Embodiment 1] 1,3 in which predetermined moisture is dissolved
- benzene -C ₄ fraction mixed solution containing butadiene with 31.6 wt% concentration (benzene 20.0% by weight and cis -
Consisting of 48.4% by weight of C ₄ fraction based on 2-butene; water content 1.95 mmol / l) 10 per hour
1 liter is supplied to a stainless steel reaction tank having a volume of 2 liters and equipped with a stirrer, and diethylaluminum chloride is supplied to adjust the water / diethylaluminum chloride molar ratio in the reaction tank solution to 0.51. 3 more
The mixture is fed to a stainless steel aging tank equipped with a stirrer and having a capacity of 3 liters, which is maintained at 5 ° C., and the resulting aging solution is supplied to a stainless steel prepolymerization tank equipped with a stirrer and having a capacity of 2.2 liters, which is maintained at 2 ° C. Cobalt octoate and the molecular weight regulator 1,5-cyclooctadiene are supplied to this prepolymerization tank (cobalt octoate 0.004 g / liter; 1,5-cyclooctadiene 0.900 g / liter). The obtained prepolymerized solution was fed to a stainless steel polymerization tank equipped with a ribbon-type stirrer having a content of 5 liters, and the temperature was adjusted to 14 at 65 ° C.
Polymerization was continued for an hour. The obtained polymerization product liquid was supplied to a mixing tank equipped with a stirrer, 1 PHR of 2,6-di-t-butyl-p-cresol was added to the rubber, and a small amount of methanol was added to stop the polymerization. Reaction 1,3-Butadiene, C ₄ fraction and benzene were removed by evaporation and vacuum dried at room temperature to obtain 12.4 kg of cis-1,4-polybutadiene.

This cis-1,4-polybutadiene has a Mooney viscosity ML _{1 + 4} (100 ° C.) 53 and an intrinsic viscosity [η] 2.
40, the microstructure was cis-1,4 structure 97.4%, trans-1,4 structure 1.4%, and 1,2-structure 1.2%. 4, per 1 g of average cobalt atom in the prepolymerization tank
100 g of cis-1,4-polybutadiene had been obtained. The average conversion of the continuous polymerization tank was 42.4%, and the catalyst activity per average cobalt atom of the continuous polymerization tank was 124,4.
10 g of cis-1,4-ributadiene at 00 g / g Co
g was dissolved in 300 ml of toluene, and the undissolved content was filtered through a 250-mesh wire net and dried, and the remaining gel content was 0.009% by weight. After continuous operation for 14 hours, no gel adhesion was observed on the prepolymerization tank, the stirring blade and the inner wall in the polymerization tank.

[Example 2] As an inert organic solvent, a cyclohexane-C ₄ fraction mixed solution (cyclohexane 20.0
% And a C ₄ cut containing cis-butene-2 as main components 48.4
%), And the water supply amount was changed to 0.86 for the water / diethylaluminum chloride molar ratio, and the temperature of the prepolymerization tank was changed to −2 ° C.
14.0 kg of 1,4-polybutadiene was obtained. This cis-1,4-polybutadiene has a Mooney viscosity ML _{1 + 4} (10
0 ° C.) 42, intrinsic viscosity [η] 2.10, microstructure is cis-1,4 structure 98.1%, trans-1,4 structure 1.
It was 1% and the 1,2-structure was 0.8%. 1,700 g of cis-1,4 per 1 g of average cobalt atom in the prepolymerization tank
-Polybutadiene was prepolymerized. The average conversion of the continuous polymerization tank was 47.3%, and the catalytic activity per average cobalt atom of the continuous polymerization tank was 139,800 g / gCo.
Then, 10 g of cis-1,4-polybutadiene was dissolved in 300 ml of toluene, and the undissolved content was filtered using a 250-mesh wire net and dried, and the remaining gel content was 0.0
It was 12% by weight. After continuous operation for 14 hours, no gel adhesion was observed on the prepolymerization tank, the stirring blade and the inner wall in the polymerization tank.

Example 3 A mixed solution of cyclohexane-C ₄ fraction (20.0% of cyclohexane and 48.4% by weight of C ₄ fraction containing cis-butene-2 as a main component) was used as an inert organic solvent. , The water supply amount was adjusted to a water / diethylaluminum chloride molar ratio of 0.84, and the temperature of the prepolymerization tank was adjusted to 10
The same procedure as in Example 1 was repeated except that the temperature was changed to ℃, cis-1,
13.5 kg of 4-polybutadiene was obtained. This system
Mooney viscosity of 1,4-polybutadiene ML _{1 + 4} (100
C) 42, intrinsic viscosity [η] 2.15, microstructure is cis-1,4 structure 98.1%, trans-1,4 structure 1.1.
%, 1,2-structure was 0.8%. 3,900 g of cis-1,4-per 1 g of average cobalt atom in the prepolymerization tank
Libutadiene was obtained. The average conversion of the continuous polymerization tank was 47.3%, the catalyst activity per average cobalt atom of the continuous polymerization tank was 135,100 g / gCo, and the cis-
10 g of 1,4-libutadiene was dissolved in 300 ml of toluene, and the undissolved portion was filtered using a 250-mesh wire net and dried, and the remaining gel content was 0.016% by weight. After continuous operation for 14 hours, no gel adhesion was observed on the prepolymerization tank, the stirring blade and the inner wall in the polymerization tank.

[0024] Example 4 inert organic solvent of cyclohexane -C ₄ fraction mixed solution (cyclohexane 10.0 wt% and cis - C ₄ fraction composed mainly of butene-2 58.4
% By weight) and the amount of water supplied was changed to a water / diethylaluminum chloride molar ratio of 0.77 and the temperature of the prepolymerization tank was changed to 0 ° C.
12.4 kg of 1,4-polybutadiene was obtained. This cis-1,4-polybutadiene has a Mooney viscosity ML _{1 + 4} (10
0 ° C.) 42, intrinsic viscosity [η] 2.17, microstructure is cis-1,4 structure 98.0%, trans-1,4 structure 1.
It was 0% and the 1,2-structure was 1.0%. 3,200 g of cis-1,4 per 1 g of average cobalt atom in the prepolymerization tank
-Libutadiene had been obtained. The average conversion rate of the continuous polymerization tank was 43.8%, the catalyst activity per average cobalt atom of the continuous polymerization tank was 129,500 g / gCo, and the cis-
10 g of 1,4-libutadiene was dissolved in 300 ml of toluene, and the undissolved portion was filtered through a 250-mesh wire net and dried, and the remaining gel content was 0.030% by weight. After continuous operation for 14 hours, no gel adhesion was observed on the prepolymerization tank, the stirring blade and the inner wall in the polymerization tank.

[Comparative Example 1] The same procedure as in Example 1 was repeated except that the water / diethylaluminum chloride molar ratio was adjusted to 0.58 and the prepolymerization tank was removed.
12.0 kg of 4-polybutadiene was obtained. This system
Mooney viscosity of 1,4-polybutadiene ML _{1 + 4} (100
C.) 42, intrinsic viscosity [η] 2.25, microstructure is cis-1,4 structure 97.7%, trans-1,4 structure 1.1.
%, 1,2-structure was 1.2%. The average conversion of the continuous polymerization tank was 42.1%, the catalyst activity per 1 g of average cobalt atom was 124,400 g / gCo, and cis-1,4-
10 g of the rebutadiene was dissolved in 300 ml of toluene, and the undissolved content was filtered through a 250-mesh wire net and dried, and the remaining gel content was 0.151% by weight. After continuous operation for 14 hours, cis-1,4-polybutadiene containing a gel component adhering to the stirring blade and the inner wall of the polymerization tank was scraped off and vacuum dried to obtain 32 g of an adhered substance.

Comparative Example 2 A mixed solution of cyclohexane-C ₄ fraction in an inert organic solvent (20.0% by weight of cyclohexane and a C ₄ fraction containing cis-butene-2 as main components 48.4).
%), The amount of water supplied was adjusted to a water / diethylaluminum chloride molar ratio of 0.75, and the cis-1,4-polybutadiene 12. was used in the same manner as in Example 1 except that the prepolymerization tank was removed. 4 kg was obtained. The Mooney viscosity ML _{1 + 4} (100 ° C.) of this cis-1,4-polybutadiene 42,
Intrinsic viscosity [η] 2.10, microstructure is cis-1,4 structure 98.3%, trans-1,4 structure 0.9%, 1,2
-Structure was 0.8%. Average conversion rate of continuous polymerization tank is 4
3.1%, the catalytic activity per 1 g of average cobalt is 12
At 7,400 g / g Co, 10 g of cis-1,4-libutadiene was dissolved in 300 ml of toluene, and the undissolved portion was filtered through a 250-mesh wire net and dried, and the remaining gel portion was 0.617 weight. %Met. After continuous operation for 14 hours, cis-1,4-polybutadiene containing a gel component adhering to the stirring blade and the inner wall in the polymerization tank was scraped off and vacuum dried to obtain 101 g of an adhered substance.

Comparative Example 3 A mixed solution of cyclohexane-C ₄ fraction in an inert organic solvent (10.0% by weight of cyclohexane and 58.4 of C ₄ fraction containing cis-butene-2 as a main component).
% By weight), the water supply amount is 0.53 in the water / diethylaluminum chloride molar ratio, and the aging tank temperature is 10 ° C.
In the same manner as in Example 1 except that the preliminary polymerization tank was removed, 12.2 kg of cis-1,4-polybutadiene was obtained. This cis-1,4-polybutadiene has a Mooney viscosity ML _{1 + 4} (100 ° C.) of 53, an intrinsic viscosity [η] of 2.35, and a microstructure of cis-1,4 structure of 97.9%, trans-.
The 1,4 structure was 1.1% and the 1,2-structure was 1.0%.
The average conversion of the continuous polymerization tank was 42.6%, and the catalyst activity per 1 g of average cobalt atom was 124,400 g / gCo.
Then, 10 g of cis-1,4-libutadiene is mixed with 3 parts of toluene.
The gel content remaining after being dissolved in 00 milliliters and undissolved was filtered using a 250-mesh wire net and dried, was 0.35.
It was 5% by weight. After continuous operation for 14 hours, cis-1,4 containing gel components attached to the stirring blade and inner wall in the polymerization tank
-Scraping off the polybutadiene and drying in vacuum gives 5
0.0 g of deposit was obtained.

[0028]

The method for producing cis-1,4-polybutadiene according to the present invention has a high stereoregularity of cis-1,4.
-Polybutadiene can be continuously produced with high yield and high catalyst efficiency, and cis-1,4-polybutadiene is substantially free of gel content. Therefore, smooth continuous operation is possible for a long period with less troubles in continuous operation.

Continuation of the front page (72) Inventor Tetsuji Nakajima 8-1 Goi Minamikaigan, Ichihara City, Chiba Ube Industries Ltd. Chiba Petrochemical Factory

Claims (1)

[Claims] 1. A method of continuously polymerizing 1,3-butadiene using a water-organoaluminum chloride-soluble cobalt compound as a catalyst component in an inert organic solvent, wherein (a) a prepolymerization temperature is -20 to 20 ° C. In the temperature range of 500 to 30,000 g of cis-per 1 g of cobalt atom.
Prepolymerization under the conditions to obtain 1,4-polybutadiene,
(B) The preliminarily polymerized polymerization solution is introduced into a continuous polymerization tank, and the polymerization temperature is in the temperature range of more than 20 ° C. to 100 ° C., and 1,3-butadiene is added to 80 g per 1 g of cobalt atom.
Cis-1, characterized by continuous polymerization of 000 g or more,
Method for producing 4-polybutadiene.