JPS6138723B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a process for the polymerization of 1,3-butadiene using a novel catalyst.

Conventionally, when 1,3-butadiene is polymerized using a catalyst obtained from a soluble cobalt compound, a trialkylaluminium, and carbon disulfide, 1,2
- It is known that polybutadiene can be obtained. Furthermore, when 1,3-butadiene is polymerized using a catalyst consisting of a soluble cobalt compound and a dialkyl aluminum halide, cis-1,4-
It is also known that polybutadiene can be obtained.

The inventors used a dialkyl aluminum halide as an organoaluminum compound to
This invention was completed as a result of research into a method for polymerizing 1,3-butadiene to produce 1,2-polybutadiene.

This invention relates to a soluble cobalt compound with the general formula
AlR ₂ X (R is an alkyl group having 2 to 8 carbon atoms,
X is a halogen atom. 1, characterized in that 1,3-butadiene is brought into contact with a catalyst consisting of dialkylaluminum halide, carbon disulfide, and an electron-donating organic compound represented by ) in a polymerization solvent to produce 1,2-polybutadiene. 3
- It relates to a method for polymerizing butadiene.

The soluble cobalt compound used in the method of this invention may be any cobalt compound that is soluble in the polymerization solvent used. For example, as such a soluble cobalt compound, a cobalt β-diketone complex or a cobalt β-keto acid ester complex is preferably used.
The β-diketone ligand of these cobalt complexes has the general formula (In the formula, R ₁ and R ₂ are each a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and R ₃
and R ₄ are each an aliphatic hydrocarbon group having 1 to 3 carbon atoms. ) β-diketones, and β-keto acid esters of the ligand include the general formula (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are the same as above.) β-keto acid esters are mentioned. Particularly preferred complexes include cobalt () acetylacetonate, cobalt () acetylacetonate,
It is a cobalt acetoacetate ethyl ester complex.

Further, as the soluble cobalt compound, a cobalt salt of an organic carboxylic acid having 6 or more carbon atoms, such as cobalt octoate, cobalt naphthenate, cobalt benzoate, etc. can be used.

Furthermore, as a soluble cobalt compound, for example, a halogenated cobalt complex, that is, a general formula COXn.Ym (3) (wherein, X is a halogen atom, particularly preferably a chlorine atom, n is an integer of 2 or 3, and Y is a ligand, and m is an integer of 1 to 4) can also be suitably used. In the above formula (3), the ligand is any ligand known to form a complex with cobalt halide, such as amines such as pyridine, triethylamine, tributylamine, and dimethylaniline;
Alcohols such as methyl alcohol and ethyl alcohol and N/N-dimethylformamide,
Examples include N·N-dialkylamide such as N·N-dimethylacetamide and N·N-diethylformamide. Particularly preferred cobalt halide complexes include cobalt chloride pyridine complexes and cobalt chloride ethyl alcohol complexes.

The organoaluminum compound used in the method of this invention has the general formula AlR ₂
8 is an alkyl group, and X is a halogen atom. ) is a dialkyl aluminum halide represented by A particularly preferred dialkyl aluminum halide is diethyl aluminum chloride.

Electron-donating organic compounds used in the method of this invention include ethers such as diethylene glycol dimethyl ether, diethylene glycol di-n-butyl ether, triethylene glycol dimethyl ether, phenylbenzyl ether, tetrahydrofuran, isoamyl ether, isopropyl ether, and dimethyl fumarate. , esters such as ethyl acetate and methyl oleate, ketones such as acetone, cyclohexanone, and acetophenone, acetals such as acetaldehyde diethyl acetal, glycols such as polyethylene glycol, aldehydes such as acetaldehyde and benzaldehyde, carbonates such as ethylene carbonate, N・N/N-dialkyl amides such as N-dimethylformamide and N/N-dimethylacetamide, dialkyl sulfoxides such as dimethyl sulfoxide, nitriles such as acetonitrile and benzonitrile, amines such as triethylamine, aniline, and quinoline, triphenylphosphine Examples include phosphine oxide such as oxide, and phosphoric acid ester such as trimethyl phosphate. Particularly preferred electron-donating organic compounds include polyethers such as diethylene glycol dimethyl ether, diethylene glycol di-n-butyl ether, and triethylene glycol dimethyl ether; aliphatic (di)carboxylic acid esters such as dimethyl fumarate and ethyl acetate; dimethylformamide,
Mention may be made of N.N-dialkyl amides such as N.N-dimethylacetamide, dialkyl sulfoxides such as dimethyl sulfoxide and phosphoric acid trialkyl esters such as trimethyl phosphate.

In the method of this invention, there is no particular restriction on the order in which the catalyst components are added, but each catalyst component is added to a polymerization solvent in which 1,3-butadiene is dissolved, and the soluble cobalt compound or carbon disulfide is added last. It is preferable to add it to

Polymerization solvents used in the method of this invention include aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons and their halides, such as benzene, toluene, xylene, n-hexane, n-heptane, Cyclohexane, chlorobenzene, methylene chloride, 1,2-dichloroethane,
Examples include 1,1,2-trichloroethane and O-dichlorobenzene.

The polymerization solvent used in the method of this invention is preferably a dehydrated one.

The amounts of each catalyst component used in the method of this invention are 0.0005 to 0.05 mol% of a cobalt compound soluble in the polymerization solvent, 0.01 to 5 mol% of dialkyl aluminum halide, and 0.001 mol% of carbon disulfide, based on 1,3-butadiene. It is preferable that it is 1 mol%.

Also, the molar ratio of dialkyl aluminum halide to soluble cobalt compound (Al/Co)
is preferably 0.8 to 200.

Furthermore, the amount of the electron-donating organic compound, which is one component of the catalyst used in the method of this invention, varies depending on the type of electron-donating organic compound used and the amount of water in the polymerization solvent, so it cannot be determined uniformly. However, it is generally preferable that the total number of moles of water and the electron-donating organic compound in the polymerization solvent is smaller than the number of moles of dialkyl aluminum halide.

Electron-donating organic compounds include polyethers such as diethylene glycol dimethyl ether, diethylene glycol di-n-butyl ether, and triethylene glycol dimethyl ether, aliphatic (di)carboxylic acid esters such as dimethyl fumarate and ethyl acetate, N/N-dimethylformamide,
When using N·N-diakylamides such as N·N-dimethylacetamide, dialkyl sulfoxides such as dimethyl sulfoxide, or phosphoric acid trialkyl esters such as trimethyl phosphate, the amount of electron-donating organic compound is , more than the number of moles of water in the polymerization solvent, preferably from 5 to 150 mol %, particularly from 10 to 100 mol %, based on the dialkyl aluminum halide. When the amount of the electron-donating organic compound is decreased, the amount of cis-1,4-polybutadiene, which is produced as a by-product along with 1,2-polybutadiene, increases; The yield of polybutadiene tends to decrease.

In the method of this invention, 1.3
The concentration of -butadiene is not particularly limited, but generally a concentration of 5 to 30% by weight based on the polymerization solvent is preferred.

Furthermore, in the method of this invention, the polymerization temperature is
A temperature of -10 to 80°C, particularly 20 to 60°C is preferred, and the polymerization pressure may be normal pressure or higher.

The 1,2-polybutadiene produced by polymerizing 1,3-butadiene by the method of this invention has a syndiotactic-1,2-structure content of 95% or more and a melting point of 190°C or more. , the reduced viscosity (η _SP /C) (measured in tetralin at 135°C) is 0.5.
~5.

If the amount of polybutadiene in the polymer production mixture increases, the viscosity of the polymer production mixture will increase, making it difficult to stir sufficiently, so make sure that the concentration of polybutadiene does not exceed about 170 g per polymer production mixture. It is desirable to control the polymerization reaction of 1,3-butadiene.

As a method for terminating the polymerization after the completion of the polymerization reaction, a known method for terminating polymerization using a catalyst obtained from a soluble cobalt compound and an organoaluminum compound can be applied. For example, alcohols that react with organoaluminum compounds,
A method in which a large amount of a polar solvent such as water is added to a polymer production mixture, or a method in which a large amount of a polar solvent is added to a polymer production mixture; inorganic acids such as hydrochloric acid and sulfuric acid; organic acids such as acetic acid and benzoic acid; A method of introducing a small amount of the above polar solvent containing ethanolamine or ammonia into the polymer production mixture, a method of introducing hydrogen chloride gas into the polymer production mixture, etc. can be employed as the polymerization termination method.

After stopping the polymerization of 1,3-butadiene, 1,2-polybutadiene is separated from the mixture, washed, and dried by a conventional method to obtain 1,2-polybutadiene.

Next, examples and comparative examples will be shown.

In the description of Examples and Comparative Examples, 1・2-
The 1,2-structure content of polybutadiene was calculated by measuring with nuclear magnetic resonance spectrum (NMR) or infrared absorption spectrum (IR). Also 1・2-
The melting point of polybutadiene was determined by the peak temperature of the endothermic curve using a differential calorimeter (DSC). Further, the ring element viscosity (η _SP /C) of 1,2-polybutadiene is a value measured at 135° C. in tetralin.

Example 1 The air was replaced with nitrogen, and 18.7 g of dried 1,3-butadiene and 191 ml of dehydrated benzene were placed in a 300 ml Erlenmeyer flask equipped with a three-way tank and a stirrer.
Add a benzene solution of 1,3-butadiene (containing 0.13 mmol of water) dissolved in 1,3-butadiene to 2.9 ml of benzene solution containing 0.075 mmol of carbon disulfide to the benzene while keeping the liquid temperature at 20°C. and 2 ml of a benzene solution containing 1.0 mmol of diethylaluminium chloride and 2 ml of a benzene solution containing 0.3 mmol of diethylene glycol dimethyl ether, followed by a benzene solution containing 0.012 mmol of cobalt octoate.
After adding 1.3 ml, 1,3-butadiene was polymerized at 20° C. for 60 minutes while stirring. The resulting polymer production mixture was added to a
ml of methanol to precipitate polybutadiene. This polybutadiene was thoroughly washed with methanol and dried under reduced pressure at 50°C to produce polybutadiene.
1.3g was obtained. After extracting this polybutadiene with boiling n-hexane for 240 minutes, insoluble matter was collected to obtain 1.2 g of powdered 1,2-polybutadiene.
The melting point of the obtained 1,2-polybutadiene is 201
℃, the 1,2-structure content was 95% or more, and the reduced viscosity was 0.97.

Example 2 Another Example 1 using diethylene glycol di-n-butyl ether instead of diethylene glycol dimethyl ether was carried out in the same manner to obtain 1.6 g of polybutadiene. 1,2-polybutadiene (1.5 g) obtained from this polybutadiene in the same manner as in Example 1 has a melting point of 197°C, a reduced viscosity of 0.87, and a 1,2-structure content of 95% or more. Ta.

Example 3 1.8 g of polybutadiene was obtained in the same manner as in Example 1, except that dimethyl fumarate was used instead of diethylene glycol dimethyl ether. 1,2-polybutadiene (1.5 g) obtained from this polybutadiene in the same manner as in Example 1 had a melting point of
The temperature is 201℃, the reduced viscosity is 1.10, and 1.2-
The structural content was 95% or more.

Example 4 Polybutadiene 1.7 was prepared in the same manner as in Example 1 except that N·N-dimethylformamide was used instead of diethylene glycol dimethyl ether.
I got g. 1,2-polybutadiene (1.5
Sample g) had a melting point of 203°C, a reduced viscosity of 1.24, and a 1,2-structure content of 95% or more.

Example 5 Polybutadiene 1.5 was prepared in the same manner as in Example 1 except that N·N-dimethyl sulfoxide was used instead of diethylene glycol dimethyl ether.
I got g. 1,2-polybutadiene (1.4
Sample g) had a melting point of 203°C, a reduced viscosity of 1.24, and a 1,2-structure content of 95% or more.

Example 6 2.5 g of polybutadiene was obtained in the same manner as in Example 1, except that acetone was used instead of diethylene glycol dimethyl ether. From this polybutadiene, powder 1.
1.3 g of 2-polybutadiene was obtained. Obtained 1.
The 2-polybutadiene had a melting point of 204°C, a reduced viscosity of 1.51, and a 1,2-structure content of 95% or more. On the other hand, n-hexane was evaporated from the n-hexane extract to obtain 1.2 g of cis-1,4-polybutadiene.

Example 7 1.1 g of polybutadiene was obtained in the same manner as in Example 1, except that acetaldehyde diethyl acetal was used instead of diethylene glycol dimethyl ether. Example 1
Extract with boiling n-hexane in the same manner as 1,2-
0.72 g of polybutadiene was obtained. Obtained 1・2-
The polybutadiene had a melting point of 203°C, a reduced viscosity of 1.31, and a 1,2-structure content of 95% or more. On the other hand, n-hexane was evaporated from the n-hexane extract to produce cis-1,4-polybutadiene.
0.39g was obtained.

Example 8 Polybutadiene was produced in the same manner as in Example 1 except that the polymerization solvent was changed from benzene to chlorobenzene.
2.9g was obtained. Example 1 from this polybutadiene
1,2-polybutadiene (2.8 g) obtained in the same manner as above has a melting point of 201°C and a reduced viscosity of 1.28.
The 1,2-structure content was 95% or more.

Example 9 Polybutadiene 2.1 was prepared in the same manner as in Example 2, except that the amount of diethylene glycol di-n-butyl ether was changed from 0.3 mmol to 0.15 mmol.
I got g. From this polybutadiene, 1.7 g of 1,2-polybutadiene was obtained in the same manner as in Example 1.
The obtained 1,2-polybutadiene had a melting point of 202°C, a reduced viscosity of 0.95, and a 1,2-structure content of 95% or more. On the other hand, by evaporating n-hexane from the n-hexane extract, cis-1,4-
0.4 g of polybutadiene was obtained.

Comparative Example 1 The same procedure as Example 1 was carried out except that diethylene glycol dimethyl ether was not added.
17.1 g of 1,4-polybutadiene was obtained.

Claims (1)

[Claims] 1 Soluble cobalt compound, consisting of a dialkyl aluminum halide represented by the general formula AlR ₂ A method for polymerizing 1,3-butadiene, which comprises bringing 1,3-butadiene into contact with a catalyst in a polymerization solvent to produce 1,2-polybutadiene.