JPH0748289A - Production of alkenylcyclohexene - Google Patents

Abstract

PURPOSE:To obtain an alkenylcyclohexene in high yield and high selectivity, by cyclodimerization of a conjugated diolefine of the chain structure with a carbon number of 4-6. CONSTITUTION:A chain conjugated diolefine with a carbon number of 4-6 is heated at a temperature of 160-210 deg.C in the presence of a cupric compound and a 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, the present invention relates to a method for producing 4-vinylcyclohexene useful as a raw material for producing styrene or ethylbenzene or alkenylcyclohexene such as 2,4-dimethyl-4-vinylcyclohexene useful as a synthetic resin raw material or 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.

Further, JP-A-47-17734 proposes a catalyst comprising a combination of a monovalent copper compound and an acidic organic compound. Since this catalyst can be used even at a high temperature of about 130 ° C., it has excellent thermal stability. However, since it is necessary to use a large amount of expensive monovalent copper compound, it is difficult to say that it has sufficient catalytic performance in industrial production.

On the other hand, in the production of alkenylcyclohexenes from a chained conjugated diolefin having 4 to 6 carbon atoms, other olefins other than the chained conjugated diolefin having 4 to 6 carbon atoms are used as raw materials. If a mixture containing acetylenes (for example, C4 fraction) can be used, its economic significance is great. This is 4 from 1,3-butadiene
Of particular industrial importance in the production of vinylcyclohexene.

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 heat stability, inexpensive and highly active and selective, and having 4 to 6 carbon atoms. It is an object of the present invention to provide a catalyst system in which a mixture such as a C4 cut can be used as is as a source of conjugated diolefins.

[0010]

According to the present invention, the above object of the present invention is to provide a chain conjugated diolefin having 4 to 6 carbon atoms in the presence of a divalent copper compound and a carboxylic acid.
It is achieved by a method for producing alkenylcyclohexenes, which comprises heating at 0 ° C to 210 ° C.

The divalent copper compound which is the catalyst used in the method of the present invention includes, for example, cupric formate, cupric acetate,
Cupric propionate, cupric cyclohexanebutyrate, cupric oleate, cupric stearate, cupric benzoate,
Cupric naphthenate, cupric phthalate, cupric oxalate,
Cupric tartrate, cupric gluconate, cupric ethylacetoacetate, ethylenediaminetetraacetic acid disodium cupric,
Cupric 3,5-diisopropyl salicylate, cupric 2-ethylhexanoate, cupric methoxy, bis (2,4-
Pentandionato) cupric, bis (2,2,6,6-tetramethyl-3,5-heptanedionato) cupric, cupric diethylthiocarbamate, bis (2-hydroxyethyl) dithiocarbamic acid Copper, bis (hexafluoroacetylacetonato) cupric, phthalocyanine cupric,
Phthalocyanine tetrasulfonic acid cupric, tetra-4-t
-Butyl phthalocyanine cupric, 4,4 ', 4 ", 4'"-
Tetraaza-29H, 31H-phthalocyanine cupric acid,
Cupric trifluoromethanesulfonate, cupric bis (trifluoro-2,4-pentanedionato), cupric benzoylacetonate, cupric oxide, cupric hydroxide, cupric cyanide, sulfite Cupric, cupric sulfate, basic cupric sulfate, cupric thiocyanate, cupric sulfide, cupric nitrate,
Cupric ammonium sulfate, cupric selenite, cupric carbonate, cupric iodide, cupric bromide, cupric chloride, cupric fluoride, cupric diammonium chloride, phosphoric acid Cupric, cupric pyrophosphate, cupric diphosphate, cupric chloride,
Inorganic or organic divalent copper compounds such as cupric tetrafluoroborate, cupric perchlorate, cupric fluorosilicate, copper chromite, and copper tungstate can be mentioned.
These may be either anhydrous or hydrated. Further, cupric cyanide-butylamine complex, cupric cyanide-2-picoline complex, cupric cyanide-propylamine complex, cupric thiocyanate-2-picoline complex, cupric sulfate-bis ( (Triphenylphosphine) complex, cupric iodide-tris (thiourea) complex, cupric iodide-bis (triphenylphosphine) complex, cupric bromide-ammine complex, cupric chloride-fumaronitrile complex, etc. The divalent copper complex compound can also be mentioned. Of these divalent copper compounds, particularly preferred are cupric acetate, cupric oxide, cupric sulfate and bis 2,4-pentanedionato cupric.

In the method of the present invention, as the chain conjugated diolefin having 4 to 6 carbon atoms, for example, 1,3-butadiene, isoprene, piperylene, 2,3-dimethyl-1,
Examples thereof include 3-butadiene and 2-methyl-1,3-pentadiene. 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. The composition of the C4 fraction is 1,3
-The concentration of butadiene is preferably 10% by weight or more, the acetylenes are practically preferably 1% by weight or less, and the amount of other hydrocarbons is not limited.

In the method of the present invention, the divalent copper compound as exemplified above is used as a catalyst. The amount of these catalysts used is preferably 0.1 to 20 mol%, more preferably 0.3 to 10 mol% based on the chain conjugated diolefin having 4 to 6 carbon atoms in the reaction mixture. is there.
The optimum amount used depends on the type of catalyst, the type of reaction solvent, the reaction temperature, the reaction time, and the like.

Examples of the carboxylic acid used in the method of the present invention include aliphatic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid and trifluoroacetic acid; cyclohexanecarboxylic acid and the like. Alicyclic carboxylic acids; benzoic acid, naphthoic acid,
Aromatic carboxylic acids such as salicylic acid, toluic acid, benzoylbenzoic acid, nitrobenzoic acid, methoxybenzoic acid, phenoxybenzoic acid, hydroxybenzoic acid, dimethoxybenzoic acid and dihydroxybenzoic acid can be mentioned. These carboxylic acids may be used alone or in admixture of two or more, and a large amount of them may be used as a solvent.

Particularly preferred among these carboxylic acids are acetic acid, benzoic acid, 2-nitrobenzoic acid, 2-benzoylbenzoic acid and 2,6-dimethoxybenzoic acid. The usage ratio of the carboxylic acid and the divalent copper compound varies depending on the type of the carboxylic acid, but in general, the carboxylic acid is often 10 times or more the molar amount of the divalent copper compound.

Although a reaction solvent may not be used, aromatic hydrocarbons such as benzene, toluene, cumene, butylbenzene and mesitylene; hexane, heptane, octane,
Aliphatic hydrocarbons such as decane; Alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, cyclooctane;
Dichlorobutane, chlorobenzene, dichlorobenzene,
Halogenated hydrocarbons such as trichlorobenzene; nitriles such as acetonitrile and benzonitrile; phenols such as phenol, cresol and xylenol; aromatic nitro compounds such as nitrobenzene and nitrotoluene; or amides such as dimethylformamide and N-methylpyrrolidone A compound that is stable under the reaction conditions of the method of the present invention can be used. Further, these solvents may be mixed and used. When a reaction solvent is used, it is preferably used in an amount of usually 0.5 to 10 times the weight of the chain conjugated diolefin having 4 to 6 carbon atoms.

In the method of the present invention, in order to suppress the polymerization of the starting C4-6 chain conjugated diolefin and the desired alkenylcyclohexene, for example, hydroquinone, t-butylcatechol, 2,6 -Ge-t
The reaction may be carried out by adding a polymerization inhibitor such as -butyl-4-methylphenol, 2,6-di-t-butyl-4-methoxyphenol. At that time, the amount of the polymerization inhibitor used is 10 with respect to the chain-like conjugated diolefin having 4 to 6 carbon atoms.
A proportion of 0 to 1,000 ppm is common.

The process of the present invention is carried out at a reaction temperature of 160-210 ° C. When the reaction temperature is lower than 160 ° C, the reaction rate is remarkably lowered, and when it is higher than 210 ° C, the selectivity is remarkably lowered, which is not preferable. The reaction time is preferably 1 to 10 hours. The reaction pressure is preferably 10 to 80 atm. The reaction can be carried out batchwise or continuously. As a method for separating and purifying alkenylcyclohexenes from a reaction mixture, a distillation method is usually adopted.

[0019]

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.

[0020]

[Table 1]

Example 1 In an autoclave made of stainless steel having an internal volume of 50 ml, 0.345 g of cupric acetate as a catalyst (1.9 mmol, 1,
2.5 mol% relative to 3-butadiene, the same applies hereinafter), 15 g of acetic acid as a carboxylic acid, and 4 mg of t-butylcatechol as a polymerization inhibitor. The autoclave was purged with nitrogen and then cooled to 0 ° C. and charged with 13 g of C 4 fraction (4.1 g as 1,3-butadiene, 75 mmol). The autoclave was immersed in an oil bath at 180 ° C. and stirred with a magnetic stirrer for 3 hours. The autoclave was cooled to about 60 ° C., the unreacted C4 fraction was collected by depressurization, and the amount of 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) were 49% and 82%, respectively.

Reference Example 1 Internal volume 100 equipped with a water condenser and an air introduction tube
In a ml flask, copper powder 0.603 g and acetic acid 77
g was added. The flask was heated while flowing air, and refluxed until the copper powder was completely dissolved (about 4 hours).
After cooling, the cupric acetate in the resulting solution was analyzed and found to have a concentration of 0.125 mmol / g.

Example 2 15.2 g of an acetic acid solution containing cupric acetate prepared in Reference Example 1 was placed in a stainless steel autoclave having an internal volume of 50 ml.
(1.9 mmol of cupric acetate) and 4 mg of t-butylcatechol as a polymerization inhibitor were added. Then, in the same manner as in Example 1, the C4 fraction was charged, reacted and analyzed. As a result, the yield and selectivity of 4-vinylcyclohexene were 51% and 83%, respectively.

Example 3 Reaction and analysis were carried out in the same manner as in Example 2 except that the reaction time was 6 hours. As a result, the yield and selectivity of 4-vinylcyclohexene were 73% and 90%, respectively.

Examples 4 to 8 and Comparative Examples 1 to 3 Reaction and analysis were carried out in the same manner as in Example 1 except that the catalyst or reaction temperature in Example 1 was changed as shown in Table 2. The results are shown in Table 2.

[0026]

[Table 2]

Example 9 Reaction and analysis were carried out in the same manner as in Example 1 except that the catalyst concentration was 5.0 mol% and the reaction time was 6 hours. As a result, the yield and selectivity of 4-vinylcyclohexene were 72% and 90%, respectively.

Example 10 The reaction and analysis were carried out in the same manner as in Example 1 except that 5 g of 2-nitrobenzoic acid and 10 g of nitrotoluene were added instead of acetic acid. As a result, the yield and selectivity of 4-vinylcyclohexene were 62% and 79%, respectively.

Example 11 The reaction and analysis were carried out in the same manner as in Example 1 except that 5 g of 2-benzoylbenzoic acid and 10 g of mesitylene were added instead of acetic acid. As a result, the yield and selectivity of 4-vinylcyclohexene were 56% and 80%, respectively.

Example 12 In Example 1, except that 5 g of 2,6-dimethoxybenzoic acid and 10 g of mesitylene were added instead of acetic acid.
Reaction and analysis were carried out in the same manner as in Example 1. As a result, the yield and selectivity of 4-vinylcyclohexene were 50% and 83%, respectively.

[0031]

INDUSTRIAL APPLICABILITY In the production of alkenylcyclohexenes by cyclodimerization of a chain conjugated diolefin having 4 to 6 carbon atoms, according to the method of the present invention, in the presence of a divalent copper compound and a carboxylic acid. By heating at 160 ° C. to 210 ° C., alkenylcyclohexenes can be obtained with good yield and selectivity.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Tsukamoto 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 Katsuo Okawa 6-1-2 Waki, Waki-machi, Kuga-gun, Yamaguchi Prefecture Mitsui Petrochemical Industry Co., Ltd. (72) Inventor Isamu Hashimoto Yamaguchi Prefecture 6-12 Waki, Waki-cho, Kuga-gun Mitsui Petrochemical Industry Co., Ltd.

Claims (2)

[Claims] 1. A linear conjugated diolefin having a carbon number of 4 to 6 in the presence of a divalent copper compound and a carboxylic acid,
A method for producing an alkenylcyclohexene, which comprises heating at 0 ° C to 210 ° C. 2. The method according to claim 1, wherein the carboxylic acid is an aromatic carboxylic acid.