JPH04122711A - Production of polybutadiene - Google Patents

Abstract

PURPOSE:To produce a polybutadiene having a low gel content and improved cost efficiency by polymerizing 1,3-butadiene at a temperature at which no phase separation occurs in the presence of a specified catalyst in a solvent based on cis-2-butene. CONSTITUTION:To a solution of 10-70wt.% 1,3-butadiene (A) in a solvent (B) comprising a 4C fraction based on cis-2-butene, desirably a mixture of cis-2- butene with trans-2-butene are added 0.1-10mmol, per mol of component A, of an organoaluminum compound (C) and 0.1-1mol, per mol of component C, of water (D). The resulting mixture is aged at -10 to 60 deg.C for a time in the range defined by the formula [wherein theta is the aging time (min), and T is the aging temperature ( deg.K)] and 0.0001-0.2mmol, per mol of component A, of a cobalt compound (E) is added to the aged mixture and reacted in a temperature range in which no phase separation occurs, whereby component A is polymerized in component B in the presence of a cobalt compound/water/organoaluminum compound catalyst comprising components C to E.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a high cis-
A method for producing 1,4-polybutadiene.

[Prior Art] Conventionally, benzene, toluene, hexane, etc. have been generally used as a polymerization solvent when 1,3-butadiene is subjected to high cis-1,4-polymerization using a Ziegler-Nanta catalyst. Ta. However, when these solvents are used as polymerization solvents, the resulting polymerization solution has a high viscosity, making stirring, heat transfer, transportation, etc. difficult. or,
Since these solvents have high boiling points, it has been difficult to recover them from the polymerization solution.

In order to solve the above problems, instead of benzene, toluene, and hexane, C
Attempts were made to use the four fractions as polymerization solvents.

As a polymerization method using a C4 fraction containing cis-2-butene as a main component as a polymerization solvent, for example, water and diethylaluminum chloride are reacted in advance to obtain chloroethylaluminoxane, and a cobalt compound is added to this. A method in which 1,3-butadiene is polymerized using the C4 fraction as a catalyst and the above C4 fraction as a solvent (Japanese Patent Publication No. 44-5238
) was attempted.

In addition, a polymerization method was attempted in which a cobalt compound-water-organoaluminum compound catalyst was prepared eight times in a paraffinic hydrocarbon having a boiling point of 150°C or higher, and 13-butashun was polymerized using the above C4 fraction as a solvent. (Tokuko Showa 47-1
1810).

Furthermore, since the hydrocarbon obtained as the bottoms when rectifying 1,3-butadiene contains 1,2-butadiene, it is added to the polymerization solution as a molecular weight regulator and a supplement for the polymerization solvent. Attempts were also made to add
-18635).

In these methods, by using a C4 fraction containing cis-2-butene as a main component as a polymerization solvent, the viscosity of the polymerization solution is greatly reduced, making stirring, heat transfer, transportation, etc. much easier. Furthermore, since the boiling point of the solvent was low, recovery of the solvent was also facilitated.

However, it is insufficient in terms of reducing gel content;
Only polybutadiene with a high gel content of 0.2% or more was obtained.

Alternatively, after preparing the catalyst in Hensen or paraffin, 1.
The method of adding 3-butadiene to a polymerization solvent solution has problems in terms of economic efficiency in industrial implementation.

[Problems to be solved by the present invention]

The present invention is a high-cis-based polymerization method in which 1,3-butashune is polymerized using a C4 fraction containing cis-2-butene as a main component as a polymerization solvent.
An object of the present invention is to provide a method for producing 1,4-polybutadiene, which allows polybutashene with a low gel content to be obtained and which is also excellent in economic efficiency.

[Structure of the Invention] The present invention involves polymerizing 13-butadiene using a cobalt compound water-organoaluminum compound catalyst in a polymerization solvent consisting of a C4 fraction containing cis-2-butene as a main component.
In the method for producing high cis-I,4-polybutadiene, (1) (in a polymerization solvent solution of aH,3-butadiene, water and an organoaluminum compound as catalyst components are mixed, θ≧) Q [1
lI7Q/T) Bow・661θ: Aging time (minutes) T: 77Aging temperature (K) for a period of time θ shown by (b) Next, a cobalt compound is added to [2] 1 in the presence of a temperature range in which phase separation does not occur.
, 3-butadiene is polymerized.

In the present invention, the ripening time θ is θ≧101N37o/71 bow/66 θ: Aging time (minutes) T: Ripening temperature (K) Must be within the range of

The ripening temperature is preferably in the range of -10 to 60'C, and in the range of O to 60'C.
A range of 50'C is particularly preferred. If the ripening temperature is lower than 10'C, the ripening time θ becomes too long, which is not preferable. Furthermore, if the aging temperature exceeds 60°C, there is a problem that the polymerization activity of the catalyst decreases.

After aging under the above conditions to deactivate cations, which are one of the major factors in gelation, a cobalt component is added to this solution, and 1,3-butadiene with high cis
,4-polymerize. This makes it possible to prevent the formation of gel during polymerization and the adhesion of gel in the polymerization tank, making it possible to continuously produce high cis-1,4-polybutadiene with a low gel content over a long period of time. .

The polymerization temperature must be below a critical temperature, that is, within a temperature range in which phase separation does not occur. The critical temperature is determined by the pressure, the type and composition of the polymerization solvent, and the concentration and molecular weight of polybutadiene. Above the critical temperature, the polymerization solution undergoes phase separation into a polybutadiene-rich phase and a polybutadiene-poor phase. Gelation is likely to occur in a phase with a high polybutadiene concentration. Therefore, if polymerization is carried out at a temperature higher than the critical temperature, gelation will proceed significantly in the phase with a high polybutadiene concentration, making it impossible to obtain cis-1,4-polybutadiene with a low gel content.

Next, the polymerization solvent, catalyst, etc. used in the present invention will be explained.

The polymerization solvent consists of a C4 fraction containing cis-2-butene as a main component. It is preferable that the total content of cis-2-butene and trans-2-butene in this C4 fraction is 50% by weight or more. and cis-2-butene, trans-
In addition to 2-butene, it may also contain hydrocarbons such as n-butane, butene-1, propane, and ethane. Particularly preferred are those consisting essentially of cis-2-butene and trans-2-butene. However, since the C4 fraction in which the total content of cis-2-butene and trans-2-butene is less than 50% by weight has low solubility of polybutadiene,
The polymerization solution tends to become non-uniform.

Therefore, it is not preferred as a polymerization solvent. This is because if the polymerization solution becomes non-uniform, gel is likely to occur.

In addition, if a polybutadiene production plant is operated for a long time, 1
．． Although cis-2-butene, which is an impurity of 3-butadiene, accumulates, this can also be preferably used as a polymerization solvent.

The catalyst was prepared by adding water and an organoaluminum compound to a polymerization solvent solution of 1,3-butadiene and aging it for a period of time θ, to which a cobalt compound was added.

As the cobalt compound, a cobalt organic acid salt Yacohard complex compound is preferable because it is soluble in cis-2-butene, which is the main component of the polymerization solvent. Specifically, cobalt octoate, cobalt naphtate, cobalt triacetylacetonate, cobalt chloride pyridine complex, cobalt chloride triphenylphosphine complex, etc. are suitable.

As the organoaluminum compound, an organoaluminum halide represented by the general formula % or an aryl group, where n is 1.5 to 2) is suitable. Specifically, diethylaluminum monochloride, di-n-butylaluminum monochloride, di-isobutylaluminum monochloride, ethylaluminum sesquichloride, etc. are suitable.

The concentration of 1,3-butadiene in the polymerization solvent solution of 1,3-butadiene and the amount of catalyst used are as follows.

The 1,3-butadiene concentration is preferably in the range of 10 to 70% by weight. A particularly preferred range is 20 to 50% by weight.

If the concentration is higher than 70% by weight, it is not preferable because it becomes difficult to control the polymerization reaction and more cationic polymers are precipitated during the ripening stage.

Moreover, if it is less than 10 parts by weight, polybutadiene cannot be efficiently produced.

The amount of catalyst used is 0.0001 to 0.2 mO of cobalt compound per moj2 of 1,3-butadiene!
, preferably 0.005 to 0.1 mmoff, and the organic aluminum compound has a concentration of 0.1 to 10 mmoff, preferably 0.2 to 8 mmoff. The amount of water is 0.1 to 1 mol, preferably 0.2 to 0.7 mol per moA of aluminum compound.

In addition, known molecular weight regulators such as 1,5-cyclooctadiene and 1,2-butadiene may be added if necessary.

Hereinafter, the present invention will be specifically explained with reference to Examples.

[Example] Examples of the present invention are shown below.

backyard ±1 In this example, 13-butadiene was polymerized by continuous operation for 24 hours.

First, a polymerization solvent solution of 1,3-butadiene was added to an inner volume of 3
! diethylaluminum monochloride was fed at a rate of 101/hr to a ripening tank with an agitator, and the feed rate was 4.59g/hr (
38.1 mmof (7)
Aged at °C with an average residence time of 18 minutes. The 1,3-butadiene polymerization solvent solution contains 45 μ/! of water! Contains 30% by weight of 1,3-butadiene, 56% by weight of cis-2-butene, and 13% by weight of trans-2-butene.
The remainder was n-butane, propane, ethane, etc.

The aged 1,3-butadiene solution that came out of the aging tank was reduced to a content of 5! 1 hour per hour in a polymerization tank with a stirrer (first polymerization tank)
(Feeding cobalt octoate at a rate of 4'/h
Omg (0,116 mmo p!,), 3.25 g (60 mmo p!,) of the molecular weight regulator 1,2-butadiene per hour.
The polymerization was carried out at a polymerization temperature of 40'' and an average residence time of 30 minutes.

Since the polybutadiene concentration of the polymerization solution in the first polymerization tank was 12% by weight, the polymerization temperature was lower than the critical temperature at this polymer concentration, and no phase separation of the polymerization solution occurred.

The polymerization solution coming out of the first polymerization tank was continuously fed to the second polymerization tank at a rate of 10ffi per hour, and 1.62g (30mmoff) of 1°2 butadiene and 40mmoff of cobalt octoate were added per hour. (0,116 mmob), and the polymerization was continued at a polymerization temperature of 49° C. and an average residence time of 30 minutes. The second polymerization tank used was of the same type as the first polymerization tank, but had a N5r content.

Since the polybutadiene concentration of the polymerization solution in the second polymerization tank was 18% by weight, the polymerization temperature was lower than the u rise temperature at this concentration.

The polymerization solution coming out of the second polymerization tank is continuously supplied to the third polymerization tank at a rate of 10β per hour, and the polymerization temperature is 55°C1.
Polymerization was continued at an average residence time of 30 minutes. The third polymerization tank has the same type of content as the first polymerization tank, with an internal capacity of 5! I used the one from

Since the polybutadiene concentration of the polymerization solution in the third polymerization tank was 22% by weight, the polymerization temperature was lower than the critical temperature at this concentration.

The polymerization solution coming out of the third polymerization tank is continuously supplied to a mixing tank equipped with a stirrer, and 2,6-t-butylphenol 7
．． A 5% by weight hexane solution was fed at 100 volumes per hour, and a small amount of methanol was further mixed to stop the polymerization.

Furthermore, 30% by volume of water was added to this polymerization solution, stirred and washed with water. After separating the water, the solvent and unreacted 1,3-butadiene were removed by devolatilization, and the obtained polybutadiene was vacuum-dried. did.

The amount of polybutadiene produced per hour is 1.35 kg.
Met. Mooney viscosity M L of this polybutadiene
,. 4 (100°C) is 42, cis-14-
The structure content was 98.0%. The gel content was as low as 0.03% by weight.

In this example, 13-butadiene was polymerized by continuous operation for 24 hours.

First, a polymerization solvent solution of 1,3-butadiene was added to an inner volume of 3
10 per hour in a aging tank with a stirrer! feeds diethylaluminium monochloride at a rate of 4.59g/hour (
The mixture was fed at a rate of 38.1 mmoffi) and aged at 30°C with an average residence time of 18 minutes.

1. Add 45 μm of water to the polymerization solvent solution of 3-butadiene.
/! containing 30% by weight of 1,3-butadiene,
Cis-2-butene is 56% by weight, trans-2-butene is 13% by weight, and the balance is h-butane, propane,
Ethane or the like was used.

The aged 1,3-butadiene solution that has come out of the aging tank is transferred to a polymerization tank (first polymerization tank) with a stirrer having an internal capacity of 51 cm per hour.
0! Delivering cobalt octoate at a rate of 80% per hour
mg (0,232 mmoff1), 12-butadiene at 4.06 g (75 mm.

The polymerization was carried out at a polymerization temperature of 40° C. and an average residence time of 30 minutes.

The polybutashun concentration of the polymerization solution in the first polymerization tank was 16% by weight, so the polymerization temperature was below the critical temperature at this concentration.

The polymerization solution coming out of the first polymerization tank is continuously supplied to a mixing tank equipped with a stirrer, and 2,6-t-butylphenol 7
．． 100 ml of 5% by weight hexane solution was supplied per hour, and a small amount of methanol was further mixed to stop the polymerization.

Further, 30% by volume of water was added to this polymerization solution, and the polymerization solution was washed with water each time. After separating the water, the solvent and unreacted polybutadiene were removed by devolatilization, and the obtained polybutadiene was vacuum-dried.

The amount of polybutadiene produced per hour was 980 g. Mooney viscosity ML of this polybutadiene. ,(
100″C) was 40, the content of cis-14-structure was 98.0%, and the gel content was 0.02
It was as low as % by weight.

Continuous polymerization of 1,3-butadiene was carried out in the same manner as in Example 2 except that the polymerization temperature in Example 2 was changed to 60''C for the sake of comparison.

During the polymerization, the polymerization solution was extracted from the polymerization tank into a pressure-resistant glass container and observed, and it was found that the solution was separated into two layers: a polyphtadiene-rich layer and a diluted layer. The polybutadiene concentration of this polymerization solution was 13% by weight based on the entire solution.

After continuous operation for 10 hours, the amount of polybutadiene produced per hour was 800 g. Mooney viscosity ML of this polybutadiene. , (100°C) is 38, and cis-
The content of 1,4-structure was 97.6%. and,
The gel content was as high as 1.2% by weight.

If this is subtraction 2, a polymerization solvent solution of 1.3-butadiene is fed to a polymerization tank with an internal capacity of 31 and equipped with a stirrer at a rate of 101 per hour, and diethylaluminum monochloride is fed at a rate of 4.59 g per hour (38,
1mmof), cobalt octoate at 80mm/hour (0
, 232 mmoffi), 1.2 butadiene per hour.
The polymer was supplied at a rate of 0.6 g (45 mmol) and polymerized at a polymerization temperature of 40° C. and an average residence time of 30 minutes.

1. Add 45 μm of water to the polymerization solvent solution of 3-butadiene.
/l, and its composition is 30% by weight of 1,3-butadiene, 56% by weight of cis-2-butene, 13% by weight of trans-2-butene, and the remainder is n-butane, propane, and ethane. etc. were used.

The polybutadiene concentration in the polymerization solution was 14% by weight.

After polymerization, the same treatment as in Example 2 was carried out to obtain polybutadiene.

After continuous operation for 10 hours, the amount of polybutadiene produced per hour was 860 g. The Mooney viscosity ML, (100°C) of this polyphtadiene was 39, and the content of cis-1,4-structure was 97°5%. The gel content was as high as 0.45% by weight.

[Effects of the present invention] In the present invention, water and an organoaluminum compound as catalyst components are added to a polymerization solvent solution of 1,3-butadiene, and after aging for a predetermined time, a cobalt compound is added and polymerization is performed. There is. The polymerization is carried out within a temperature range in which phase separation does not occur.

Therefore, even though a C4 fraction containing cis-2-butene as a main component is used as a polymerization solvent, polybutadiene with an extremely low gel content can be obtained.

Claims (1)

[Claims] (1) Using the C_4 fraction containing cis-2-butene as a main component as a polymerization solvent, 1,3-butadiene is polymerized using a cobalt compound-water-organoaluminum compound catalyst, resulting in high-cis-1,4-polybutadiene. [1] (a) Water and an organoaluminum compound in a polymerization solvent solution of 1,3-butadiene, θ≧10^[^(^1^3^7^0^/^T^ )^-^
3^. ^6^6^] θ: Aging time (minutes) T: Aging temperature (K) Aging is performed for a period of time θ, (b) then a cobalt compound is added, and [2] the presence of this polymerization catalyst is A method for polymerizing cis-1,4-polybutadiene, which comprises polymerizing 1,3-butadiene at a temperature range in which phase separation does not occur.