JPH0748290A - Production of alkenylcyclohexenes - Google Patents

Abstract

PURPOSE:To obtain an alkenylcyclohexene in good yield and good selectivity, by cyclodimerization of a chain conjugated diolefine with a carbon number of 4-6. CONSTITUTION:A chain conjugated diolefine with a carbon number of 4-6 is heated in the presence of a cuprous compound and an aromatic carboxylic acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing alkenylcyclohexenes. More specifically, it relates to a method for producing 4-vinylcyclohexene useful as a raw material for producing styrene or ethylbenzene, a synthetic resin raw material, and an alkenylcyclohexene such as 2,4-dimethyl-4-vinylcyclohexene useful as a fragrance.

[0002]

2. Description of the Related Art Alkenylcyclohexenes are converted into 1,3
The following catalyst systems have been proposed so far in the method for producing by cyclization dimerization of a chain conjugated diolefin having 4 to 6 carbon atoms such as butadiene and isoprene.

JP-B-44-29451 proposes a three-way catalyst system comprising an iron compound such as tris (acetylacetonato) iron, a phosphorus compound such as ethylenebis (diphenylphosphine), and an alkylaluminum such as triethylaluminum. Has been done. However,
The low selectivity of the desired product, 4-vinylcyclohexene, is a problem in industrial production.

Japanese Patent Publication No. 49-47737 proposes a two-way catalyst system comprising iron carbonyl such as iron pentacarbonyl and a nitrosylating agent such as nitric oxide, and JP-A-49-93337. The publication discloses a binary catalyst system composed of sodium nitrosyltricarbonyliron (I) and the like and dinitrosylcobalt bromide and the like. These catalyst systems have the advantage of having high catalytic activity. However, there is a problem in thermal stability such that the reaction must be started at a low temperature of −20 ° C. or lower.

US Pat. No. 4,144,278 discloses
A two-way catalyst system or a three-way catalyst system containing dinitrosyl iron chloride and a reducing agent such as tin has been proposed. Although the thermal stability of these catalyst systems is considerably improved, it is still necessary to carry out the reaction at about 60 ° C. or lower, and it is said that the catalyst system has sufficient thermal stability for recovery and reuse. Hard to say.

Japanese Unexamined Patent Publication (Kokai) No. 47-17734 proposes a catalyst comprising a combination of a monovalent copper compound and an acidic organic compound. Here, as the acidic organic compound,
Aliphatic carboxylic acids such as formic acid and acetic acid or phenol compounds such as phenol, cresol and xylenol are disclosed, and aromatic carboxylic acids are not described. Since this catalyst can be used even at a high temperature of about 130 ° C., it has excellent thermal stability, but has a problem of low activity.

In the production of alkenylcyclohexenes from a chained conjugated diolefin having 4 to 6 carbon atoms, as a raw material, other olefins and acetylenes other than the chained conjugated diolefin having 4 to 6 carbon atoms are used. If a mixture containing is usable, it has great economic significance. This is 1,3
Of particular importance in the production of 4-vinylcyclohexene from butadiene.

Among the catalyst systems proposed so far,
The C4 fraction obtained by the thermal decomposition of naphtha can be used as it is as a source of 1,3-butadiene, as described in JP-B-44-29451 and JP-A-49-9333.
Each catalyst system described in Japanese Patent Publication No. 7 is known. However, both catalyst systems have serious drawbacks in industrial production, as mentioned above.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of conventional catalysts, and
It is an object of the present invention to provide a method for producing alkenylcyclohexenes by cyclodimerization of a chain conjugated diolefin of ~ 6. That is, in the production of alkenylcyclohexenes from a chain-like conjugated diolefin having 4 to 6 carbon atoms, it is excellent in safety and thermal stability, has high activity and selectivity, and has 4 to 6 carbon atoms in chain form. C4 as a diolefin source
It is an object of the present invention to provide a catalyst system in which a mixture such as a cut can be used as is.

[0010]

According to the present invention, the above object of the present invention is to heat a chain conjugated diolefin having 4 to 6 carbon atoms in the presence of a monovalent copper compound and an aromatic carboxylic acid. It is achieved by a method for producing alkenylcyclohexenes characterized in that

In the method of the present invention, examples of the monovalent copper compound include cuprous oxide, cuprous sulfide, cuprous hydroxide, cuprous acetate, cuprous propionate, cuprous benzoate. , Cuprous sulfate, cuprous nitrate, cuprous carbonate, cuprous iodide, cuprous bromide, cuprous chloride, cuprous fluoride and cuprous cyanide. . Of these compounds, cuprous oxide, cuprous hydroxide, cuprous acetate and cuprous benzoate are particularly preferable. The amount of the monovalent copper compound used is preferably 0.1 to 20 mol%, more preferably 0.5 to 10 mol, based on the chain conjugated diolefin having 4 to 6 carbon atoms in the reaction mixture. %.

In the method of the present invention, benzoic acid and its derivative are preferably used as the aromatic carboxylic acid. Examples of the substituent of the benzoic acid derivative include a nitro group, an acyl group, an alkyl group, a phenyl group, a halogen-substituted alkyl group, a halogen, an amino group and an amide group. The number of these substituents is 1 to 5, preferably 1 to 2.
And the substitution position is not particularly limited.

Specific examples of the aromatic carboxylic acid include benzoic acid, 2-nitrobenzoic acid, 3-nitrobenzoic acid, 4-nitrobenzoic acid, 2,4-dinitrobenzoic acid,
3,4-dinitrobenzoic acid, 3,5-dinitrobenzoic acid,
2-phthalaldehyde acid, 3-phthalaldehyde acid, 4
-Phthalaldehyde acid, 2-acetylbenzoic acid, 4-acetylbenzoic acid, 2-benzoylbenzoic acid, 3-benzoylbenzoic acid, 4-benzoylbenzoic acid, 2,3-dimethylbenzoic acid, 2,4-dimethylbenzoic acid 2,5-Dimethylbenzoic acid, 2,6-Dimethylbenzoic acid, 3,4-Dimethylbenzoic acid, 2-Phenylbenzoic acid, 4-Phenylbenzoic acid, 2-Trifluoromethylbenzoic acid, 4-Trifluoromethyl Benzoic acid, 2-chlorobenzoic acid, 3-chlorobenzoic acid, 4-chlorobenzoic acid, 2-bromobenzoic acid, 3-bromobenzoic acid, 4-bromobenzoic acid, 2-fluorobenzoic acid, 3-fluorobenzoic acid , 4-fluorobenzoic acid, 2,3-dichlorobenzoic acid, 2,4-dichlorobenzoic acid, 2,5-dichlorobenzoic acid, 2,6-dichlorobenzoic acid, 3,4-dichloro Benzoic acid, 3,5-dichlorobenzoic acid, 2,3-difluorobenzoic acid, 2,4-difluorobenzoic acid, 2,5-difluorobenzoic acid, 2,6-difluorobenzoic acid, 3,4-difluorobenzoic acid Acid, pentafluorobenzoic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid and phthalamic acid. Among these compounds, benzoic acid and a benzoic acid derivative having a nitro group or a benzoyl group are particularly preferable.

The amount of the aromatic carboxylic acid used is 1 to 300 times mol, preferably 5 to 1 times, the mol of the monovalent copper compound.
The molar amount is 00 times, more preferably 10 to 50 times.

In the method of the present invention, the chain conjugated diolefin having 4 to 6 carbon atoms is, for example, 1,3-butadiene, isoprene, piperylene, 2,3-dimethyl-1,3.
-Butadiene, 2-methyl-1,3-pentadiene and the like can be mentioned. These may be purified, or may be unpurified and used in the same manner. For example, the C4 fraction containing 1,3-butadiene obtained by the thermal decomposition of naphtha can be used as it is. As for the composition of the C4 fraction, the concentration of 1,3-butadiene is preferably 10% by weight or more, and the acetylene is practically preferably 1% by weight or less,
There is no limitation on the type and amount of other hydrocarbons.

Although it can be carried out without using a reaction solvent, it is usually preferable to use it, and aromatic hydrocarbons such as benzene, toluene, cumene, butylbenzene and mesitylene; and aliphatic hydrocarbons such as hexane, heptane, octane and decane. Hydrocarbons; cyclohexane, methylcyclohexane,
Alicyclic hydrocarbons such as cyclooctane; dichlorobutane,
Halogenated hydrocarbons such as chlorobenzene, dichlorobenzene and trichlorobenzene; phenol compounds such as phenol and cresol; nitro compounds such as nitrobenzene and nitrotoluene; ethers such as anisole and ethylphenyl ether; dimethylformamide, N
Compounds that are stable under the reaction conditions of the process of the invention can be used, such as amides such as -methylpyrrolidone. Among them, aromatic hydrocarbons, phenol compounds or nitro compounds are preferable, and phenol compounds and nitro compounds are more preferable. Further, these solvents may be mixed and used. When the reaction solvent is used, it is usually used preferably in an amount of 0.5 to 10 times by weight the amount of the aromatic carboxylic acid.

In the method of the present invention, in order to suppress the polymerization of chain-like conjugated diolefins having 4 to 6 carbon atoms and alkenylcyclohexenes, for example, hydroquinone, t-butylcatechol, 2,6-di-t-butyl- The reaction may be carried out by adding a polymerization inhibitor such as 4-methylphenol or 2,6-di-t-butyl-4-methoxyphenol.
At that time, the amount of the polymerization inhibitor used is generally 200 to 2,000 ppm with respect to the chain conjugated diolefin having 4 to 6 carbon atoms.

The reaction temperature is preferably 100 to 250.
C., more preferably 150 to 200.degree. C., and the reaction time is preferably 1 to 10 hours. The reaction pressure is not particularly specified, but is usually 10 to 80 atm. The reaction can be carried out batchwise or continuously.

As a method for separating and purifying alkenylcyclohexenes from the reaction mixture, a distillation method is usually adopted.

[0020]

The present invention will be described below with reference to examples.
The invention is not limited by these examples. In the following Examples and Comparative Examples, the raw material C4 fraction used had the composition shown in Table 1 obtained by the thermal decomposition of naphtha.

[0021]

[Table 1]

Example 1 0.140 g (0.98 mmol, cuprous oxide) of cuprous oxide as a catalyst was placed in a stainless steel autoclave having an internal volume of 50 ml.
(1.3 mol% based on 1,3-butadiene), 4.52 g (20.0 mmol) of 2-benzoylbenzoic acid, and 4 mg of t-butylcatechol as a polymerization inhibitor were added. The autoclave was purged with nitrogen, and 10.0 g of phenol as a solvent was added, followed by cooling to 0 ° C. and 13.0 g of C4 fraction (1,3-).
4.1 g (75.7 mmol) of butadiene was charged. The autoclave was immersed in an oil bath at 180 ° C., and a reaction was performed with stirring with a magnetic stirrer for 3 hours. The autoclave was cooled to about 60 DEG C., the unreacted C4 fraction was collected by depressurization, and the amount of unreacted 1,3-butadiene was analyzed by gas chromatography. The reaction mixture was diluted with toluene and analyzed by gas chromatography. As a result, the yield and selectivity of 4-vinylcyclohexene (all are based on 1,3-butadiene, the same applies hereinafter) are 75% each.
% And 87%.

Examples 2 to 5 Reaction and analysis were carried out in the same manner as in Example 1 except that the catalyst, aromatic carboxylic acid, solvent, reaction temperature, or reaction time in Example 1 were as shown in Table 2. Was done. The results are shown in Table 2.

[0024]

[Table 2]

Comparative Example 1 0.140 g (0.98 mmol, 1,98 mmol) of cuprous oxide was used as a catalyst in a stainless steel autoclave having an internal volume of 50 ml.
1.3 mol% relative to 3-butadiene), t of the polymerization inhibitor
-Butylcatechol 4 mg was added. The autoclave was purged with nitrogen, 1.20 g (20.0 mmol) of acetic acid and 10.0 g of phenol as a solvent were added, and the mixture was cooled to 0 ° C. and charged with 13.0 g of C4 fraction. 1 autoclave
It was immersed in an oil bath at 80 ° C. and reacted with stirring with a magnetic stirrer for 3 hours. After the reaction, unreacted C was prepared in the same manner as in Example 1.
The 4 fractions and the reaction solution were analyzed. As a result, 4-
Vinylcyclohexene yield and selectivity are 40% each
And 70%.

Comparative Examples 2 to 5 In Comparative Example 1, the reaction and analysis were carried out in the same manner as in Comparative Example 1 except for the catalyst, aliphatic carboxylic acid, solvent and reaction conditions shown in Table 3. The results are shown in Table 3.

[0027]

[Table 3]

[0028]

INDUSTRIAL APPLICABILITY In the production of alkenylhexenes by cyclodimerization of a chain conjugated diolefin having 4 to 6 carbon atoms, the method of the present invention comprises a monovalent copper compound and an aromatic carboxylic acid. By using a catalyst, alkenylcyclohexenes can be obtained with good yield and selectivity.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kenji Iwamasa 6-1-2 Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture Mitsui Petrochemical Industries Ltd. (72) Satoshi Inoki Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture 6-1-2 Mitsui Petrochemical Industry Co., Ltd. (72) Inventor Isao Hashimoto 6-1-2 Waki Waki-machi, Kuga-gun, Yamaguchi Prefecture Mitsui Petrochemical Industry Co., Ltd.

Claims (2)

[Claims] 1. A method for producing an alkenylcyclohexene by heating a chain conjugated diolefin having 4 to 6 carbon atoms in the presence of a monovalent copper compound and an acidic organic compound, wherein an aromatic carboxylic acid is used as the acidic organic compound. A method for producing alkenylcyclohexenes, which comprises using an acid. 2. The method according to claim 1, wherein a phenol compound or a nitro compound is used as a solvent.