JP2001031595A - Production of 1,3-cycloalkadiene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially possible method for producing 1,3- cyclohexadiene from 1,2-dichlorocyclohexane in high yield while by-producing extremely small amount of 1,4-cyclohexadiene. SOLUTION: This method for producing 1,3-cycloalkadiene by reacting a 1,2-dihalocyclohexane in the presence of a bipolar nonprotonic solvent and a base comprises adding water to the reaction system and carrying out the reaction at 160-300 deg.C reaction temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing 1,3-cycloalkadiene which is an alicyclic conjugated diene compound. More specifically, the present invention relates to a method for producing 1,3-cycloalkadiene by a dehydrohalogenation reaction of 1,2-dihalocycloalkane.

[0002]

2. Description of the Related Art In recent years, 1,3-cyclohexadiene has been
It is known that high heat resistance and high rigidity polymer can be obtained by living anionic polymerization, and is an industrially important monomer. Various methods for synthesizing 1,3-cyclohexadiene have been proposed so far.
1,4-cyclohexadiene, which is an isomer of cyclohexadiene, is included as a by-product. By the way, 1,3
When obtaining a high polymer from cyclohexadiene, if the 1,4-cyclohexadiene is contained as an impurity, it is known that polymerization does not proceed smoothly and only a low molecular weight product is obtained, or polymerization does not proceed at all. (Eg, Polym. Prepr. (Am. Chem. So
c. Div. Poym. Chem. ) 12, p. 402
(1971)).

[0003] The present inventors have studied and found that the content of 1,4-cyclohexadiene must be at least 2% or less in order to obtain the desired high molecular weight product. . As a method for synthesizing 1,3-cyclohexadiene, a dehydrobromination reaction from 1,2-dibromocyclohexane is performed in triethylene glycol using 1,2 cyclohexadiene.
-Dibromocyclohexane is reacted with potassium hydroxide to obtain 1,3-cyclohexadiene (Organikum, 5. Aufl., S.22).
6, VED Deutscher Verlag de
r Wissenschaften, Berlin
1965). However, in this method, in addition to 1,3-cyclohexadiene, a large amount of benzene and 1,4-cyclohexadiene are by-produced, and the purity of 1,3-cyclohexadiene is low. The boiling points of 1,3-cyclohexadiene and 1,4-cyclohexadiene are close to 80 ° C. and 89 ° C., respectively, and there is a problem that it is difficult to separate both substances by distillation because they azeotrope.

Further, 1,3-dibromocyclohexane is heated in a hexamethylphosphoric triamide to 160 ° C. using a mixture of lithium chloride and lithium carbonate, so that 1,3-cyclohexadiene has 82% (J. Org. C).
hem. , 49, 2650 (1984)). However, when the present inventors carried out the reaction under the conditions described in this document, 1,3-cyclohexadiene was obtained in a yield of 47%, but at the same time, cyclohexene was 30%, and benzene was 23%, which was a secondary. Organism was produced in large quantities. By the way, since cyclohexene and benzene have boiling points close to 1,3-cyclohexadiene, it is difficult to separate them by distillation. Therefore, high-purity 1,3-cyclohexadiene cannot be obtained in high yield.

In addition to these methods, various methods for synthesizing 1,3-cyclohexadiene using 1,2-dibromocyclohexane as a raw material have been proposed. After the first stage reaction of 1,2-dibromocyclohexane with sodium in methanol to obtain 2.2% of 1,3-cyclohexadiene and 70% of 3-methoxycyclohexene, the 3-methoxycyclohexene is further converted to A method has been proposed for reacting with 85% phosphoric acid in triethylene glycol to obtain 1,3-cyclohexadiene in a yield of 82%,
From 1,2-dibromocyclohexane in 57% yield,
It has been reported that 3-cyclohexadiene was obtained (Chem. Ber., 100, p. 1764 (196).
7)).

Further, it has been reported that high purity 1,3-cyclohexadiene can be obtained by reacting 1,2-dibromocyclohexane with sodium ethoxide to synthesize 3-ethoxycyclohexene, followed by a dealcoholization reaction. (Mitt. Schles. Kohlenf
orsh. -Inst. Kaiser-Wilheim
-Ges. 2, 97 (1925), C.I. 1926, 23
43).

However, in the method of obtaining 1,3-cyclohexadiene from these 1,2-dibromocyclohexane via 3-alkoxy-1-cyclohexene by dealcoholation reaction, the reaction process is performed in two steps. There has been a need for a one-step manufacturing method that can be manufactured more easily.

On the other hand, a method of synthesizing 1,3-cyclohexadiene from 1,2-dichlorocyclohexane in one step has also been reported. It has been reported that cyclohexadiene can be obtained in one step with a high yield by reacting at 150 to 170 ° C. in a solution or suspension of sodium hydroxide and polyglycol (DE1090202). However, nothing is described about the purity of the obtained 1,3-cyclohexadiene, and there is no description of the amount of 1,4-cyclohexadiene by-produced. According to the results of experiments conducted by the present inventors under the conditions described in the specification, the yield of cyclohexadiene increases as the reaction temperature increases and as the molecular weight of polyglycol increases, but at the same time, 1,4-
The content of cyclohexadiene also tends to increase, and the content of 1,4-cyclohexadiene in 1,3-cyclohexadiene is at least 2% or more even when various reaction conditions are changed. It was unsuitable as 1,3-cyclohexadiene as a raw material for production.

[0009]

The by-product of 1,4-cyclohexadiene from 1,2-dichlorocyclohexane, which is the main product formed by the chlorination of cyclohexene, is extremely small, and a high yield which is industrially practicable. An object of the present invention is to provide a method for producing 1,3-cyclohexadiene.

[0010]

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, surprisingly, 1,2-dihalocycloalkane was removed in the presence of a dipolar aprotic solvent and a base. By carrying out the reaction under a specific temperature condition in the presence of water when the hydrogen halide reaction is carried out, high-purity 1,3-cycloalkadiene with extremely little by-product of 1,4-cycloalkadiene is obtained. Have been found to be easily produced in high yield, and have led to the present invention.

That is, the present invention provides (1) a method for obtaining a 1,3-cycloalkadiene by reacting a 1,2-dihalocycloalkane in the presence of a dipolar aprotic solvent and a base. A process for producing 1,3-cycloalkadiene, characterized by adding water and reacting at a reaction temperature of 160 ° C. or more and 300 ° C. or less, (2) a hydroxide of an alkali metal or an alkaline earth metal as a base A method for producing a 1,3-cycloalkadiene according to the above (1), which is at least one selected from the group of carbonates;
(3) The 1,1 of the above (1) or (2), wherein the 1,2-dihalocycloalkane is 1,2-dichlorocyclohexane or 1,2-dibromocyclohexane.
A process for producing 3-cycloalkadiene, (4) the 1,3-cycloalkane according to (1), (2) or (3), wherein the dipolar aprotic solvent is an amide compound and / or a sulfoxide compound; Alkadiene production method, (5)
(6) the method for producing a 1,3-cycloalkadiene according to any one of the above (1) to (4), wherein the dipolar aprotic solvent is 1-methyl-2-pyrrolidinone;
Wherein the 1,2-dihalocycloalkane is a 1,2-dihalocycloalkane containing a 3-halocycloalkene;
-A process for producing cycloalkadiene, (7) the amount of water present in the reaction system is 1,2-dihalocycloalkane,
The method for producing a 1,3-cycloalkadiene according to any one of the above (1) to (6), wherein the molar ratio is from 0.1 to 1000 moles, and (8) water, a dipolar aprotic solvent and a base. The 1,3-cycloalkane according to any one of claims 1 to 7, wherein the 1,2-dihalocycloalkane is added to the solution after the contained solution is heated to 160 ° C or more and 300 ° C or less. Diene production method.

Hereinafter, the present invention will be described in detail. The 1,2-dihalocycloalkane in the present invention is preferably 5
A 1,2-dihalocycloalkane having from 12 to 12 ring members, specifically 1,2-dichlorocyclopentane,
2-dibromocyclopentane, 1,2-diiodocyclopentane, 1,2-dichlorocyclohexane, 1,2-
Dibromocyclohexane, 1,2-diiodocyclohexane, 1,2-dichlorocycloheptane, 1,2-dibromocycloheptane, 1,2-diiodocycloheptane, 1,2-dichlorocyclooctane, 1,2-dibromocyclo Octane, 1,2-diiodocyclooctane,
1,2-dichlorocyclononane, 1,2-dibromocyclononane, 1,2-diiodocyclononane, 1,2-dichlorocyclodecane, 1,2-dibromocyclodecane,
1,2-diiodocyclodecane, 1,2-dichlorocycloundecane, 1,2-dibromocycloundecane,
1,2-diiodocycloundecane, 1,2-dichlorocyclododecane, 1,2-dibromocyclododecane,
1,2-diiodocyclododecane. Preferred are 1,2-dichlorocyclohexane and 1,2-dibromocyclohexane. The 1,2-dihalocycloalkane has a cis-form and a trans-form, but either may be used as a raw material.

In the present invention, 95 mol% or less of 3-halocycloalkene may be mixed with 1,2-dihalocycloalkane. The 3-halocycloalkene easily undergoes the elimination reaction of hydrogen chloride by the same reaction as in the case of the 1,2-dihalocycloalkane of the present invention,
1,3-Cycloalkadiene is formed. When 4-halocycloalkene is reacted through the reaction step of the present invention, 1,4-cycloalkadiene is by-produced. Therefore, the content of the 4-halocycloalkene relative to the 1,2-dihalocycloalkane is preferably 4 mol% or less, more preferably 2 mol% or less.

Such 1,2-dihalocycloalkenes can be produced by various methods. For example, 1,2-dihalocycloalkanes can be obtained as main products by halogenation of cycloalkenes. . The obtained mixture of halides can be separated by a purification method such as distillation.

The dipolar aprotic solvents used in the present invention include ketones, sulfoxides, nitriles,
Oxyethers, amides, phosphoric acid triamides and the like can be mentioned. Specific examples include acetone, 3-pentanone, 4-heptanone, 5-nonanone, dimethylsulfoxide (DMSO), acetonitrile, fumaronitrile,
Ethylene glycol dimethyl ether (DME), diethylene glycol dimethyl ether (DIGLYM)
E), triethylene glycol dimethyl ether (TR
IGLYME), tetramethylene glycol dimethyl ether, dimethylformamide (DMF), dimethylacetamide (DMAC), diethylformamide, diethylacetamide, tetramethylurea, hexamethylphosphoric triamide (HMPA), 1-methyl-2-pyrrolidinone (NMP), 1,3-dimethyl-2-imidazolidinone and the like.

These solvents mix with both water and organic solvents. Among these, amide-based and sulfoxide-based solvents are preferable, and 1-methyl-2-pyrrolidinone is more preferable. 1-Methyl-2-pyrrolidinone can be mixed with water and an organic substance, particularly 1,2-dihalocycloalkane, at an arbitrary ratio, and can also dissolve inorganic salts to some extent. In addition, even if the temperature is raised to 300 ° C. in the presence of a base, the rate of decomposition of 1-methyl-2-pyrrolidinone as a solvent is low, which is preferable. These solvents may be used alone or as a mixture of two or more.

The base used in the present invention includes:
For example, hydroxides, carbonates, bicarbonates, hydrides, alkyl metals and the like of alkali metals, alkaline earth metals, and lanthanide metals can be mentioned. Specific examples include sodium hydroxide, potassium hydroxide, calcium hydroxide, hydroxides such as lithium hydroxide, sodium carbonate, potassium carbonate,
Examples thereof include carbonates such as calcium carbonate, hydrogen carbonates such as sodium hydrogen carbonate, potassium hydrogen carbonate, and calcium hydrogen carbonate, and hydrides such as sodium hydride and calcium hydride. Of these, alkali metal hydroxides and alkali metal and alkaline earth metal carbonates are preferred. When an alkali metal hydroxide is used, the yield of 1,3-cycloalkadiene is improved.

When the carbonate of an alkali metal or alkaline earth metal is used, the amount of by-product 1-chlorocycloalkene is increased as compared with the case of using a hydroxide of an alkali metal. -The amount of by-products of cycloalkadiene is reduced, and the purity of 1,3-cycloalkadiene after purification can be improved. Further, these bases may be used alone or as a mixture of two or more.

The amount of the base used is preferably 1.5 times to 20 times the mole of 1,2-dihalocycloalkane, more preferably 1.8 times to 10 times the mole. When the amount of the base used is small, the conversion of 1,2-dihalocycloalkane decreases, and a satisfactory yield cannot be obtained. Conversely, as the amount of the base is increased, the reaction rate is increased and the conversion is improved. However, the effect of accelerating the reaction is small even if it is used more than 20 times by mole, and most of the base is wasted.

Further, a halide of an alkali metal or an alkaline earth metal such as lithium chloride or calcium chloride may be added. These compounds are generally used in an amount of 2 molar equivalents or less based on the 1,2-dihalocycloalkane.
By adding these compounds, by-products 1,4
-Although the amount of cycloalkadiene produced is slightly reduced,
Problems arise in treating these compounds, which are costly and waste.

In order to accelerate the reaction, a phase transfer catalyst may be added. Examples of the phase transfer catalyst include quaternary ammonium salts such as tricaprylylmethylammonium chloride, phosphonium salts such as hexadecyltri-n-butylphosphonium bromide, and crown ethers such as 18-crown-6-ether. The phase transfer catalyst affects only the reaction rate, and the conversion rate of the raw material 1,2-dihalocycloalkane is improved by adding the phase transfer catalyst.

In the present invention, the amount of water added to the reaction system is preferably from 0.1 to 1000 times, preferably from 1 to 100 times, based on 1,2-dihalocycloalkane.
The molar ratio is more preferably not more than 5 times, particularly preferably not less than 5 times and not more than 50 times. At the reaction temperature of the present invention, the reaction solution is preferably separated into two layers, an aqueous layer and an organic layer. When the amount of water is less than 0.1 mole, 1,4-
The amount of cycloalkadie produced is undesirably increased. On the other hand, if the amount exceeds 1000 times, the conversion rate of 1,2-dihalocycloalkane becomes slow, and the amount of solvent for the reaction substrate increases, so that it becomes useless.

The amount of the dipolar aprotic solvent relative to the 1,2-dihalocycloalkane is not particularly limited, but is preferably 0.5 to 100 moles. More preferably, the molar ratio is 1 to 50 moles. 1,2-Dihalocycloalkane is hardly soluble in water,
1,2-dihalocycloalkane by increasing the amount of dipolar aprotic solvent mixed in any proportion with
The conversion rate of the dihalocycloalkane is increased. 1,2-
If the amount of the dipolar aprotic solvent is less than 0.5 mol per mol of the dihalocycloalkane, the conversion rate of the 1,2-dihalocycloalkane is unfavorably low, whereas if it exceeds 100 mol, the amount of the solvent becomes too large. Wasteful.

In the reaction of the present invention, 1,2-dihalocycloalkane, water, a dipolar aprotic solvent and a base may be charged together to raise the temperature. After charging the base and raising the temperature to the reaction temperature, the 1,2-dihalocycloalkane may be added. However, it is more preferable to add the 1,2-dihalocycloalkane after raising the reaction temperature. If they are batched,
Before the temperature rises to the reaction temperature, the raw material 1,2-dihalocycloalkane may be converted to produce a 3-hydroxy-1-cycloalkene. In particular, when the time required to reach the reaction temperature is long, this tendency becomes stronger.

The reaction temperature in the present invention is 160 ° C. or higher and 3
It is necessary that the temperature be in the range of 00 ° C. or less, preferably in the range of 165 ° C. or more and 250 ° C. or less, more preferably 17
0 ° C or higher and 240 ° C or lower. When the reaction temperature is lower than 160 ° C., the 1,2-dihalocycloalkane as a raw material is easily subjected to a nucleophilic substitution reaction even when converted, and 3-hydroxy-1-cycloalkene becomes a main product. As the reaction temperature increases, the rate at which 1,2-dihalocycloalkanes undergo a nucleophilic substitution reaction tends to decrease, and the amount of 1,3-cycloalkadiene produced by the elimination reaction tends to increase. 300 ℃
At temperatures above 1,2-dihalocycloalkanes are converted, but 1,4-
It is not preferable because the amount of by-products of cycloalkadiene increases.

The reaction pressure in the present invention is preferably in the range of 1 to 100 atm, more preferably 2 to 50 atm. Only the vapor pressure of water or the like naturally applied during the reaction may be used, or the pressure in the system may be further increased by nitrogen or air. The 1,3-cycloalkadiene produced by the reaction of the present invention is by-produced by the present reaction, and after removing the halide of the base that has not completely dissolved in the mixed solution and thus precipitated by filtration, is isolated by a purification operation such as distillation. Can be.

The obtained 1,3-cyclohexadiene is
For example, a known method (for example, WO94 / 28038, etc.)
(1,3-cyclohexadiene) homopolymer having a high average molecular weight can be obtained. Also,
By copolymerizing with another monomer, a copolymer containing 1,3-cyclohexadiene unit can be obtained.

[0028]

Embodiments of the present invention will be described below in detail.

[0029]

Example 1 11.25 g (625 mmol) of water and 1-methyl-2 were placed in a 50 ml Hastelloy autoclave.
-11.25 g (113.5 mmol) of pyrrolidinone,
After charging 5.6 g (140 mmol) of sodium hydroxide and raising the temperature of the autoclave to 180 ° C.,
10.53 g of 1,2-dichlorocyclohexane (68.
8 mmol) with a pump at a rate of 1 ml / min.
Stirred for hours. After completion of the reaction, the reaction mixture was cooled to room temperature to remove precipitated sodium chloride. When the filtrate was analyzed by gas chromatography, the conversion of 1,2-dichlorocyclohexane was 100%. The selectivities of the obtained reactants are as follows. 1,3-cyclohexadiene 89.5 mol% 1,4-cyclohexadiene 0.2 mol% cyclohexene 0.8 mol% benzene 1.6 mol% 3-hydroxy-1-cyclohexene 3.0 mol% 2,2′-dicyclohexenyl ether 2.1 mol% 1-chlorocyclohexene 2.8 mol%

[0030]

Example 2 An experiment was conducted in the same manner as in Example 1 except that sodium hydroxide was replaced with calcium carbonate. The charged amount of calcium carbonate is 14.0 g (140 mmol). After the reaction was completed, the filtrate was analyzed by gas chromatography, and the conversion of 1,2-dichlorocyclohexane was found to be 1
00%. The selectivities of the obtained reactants are as follows. 1,3-cyclohexadiene 85.3 mol% 1,4-cyclohexadiene 0.01 mol% cyclohexene 0.5 mol% benzene 1.8 mol% 3-hydroxy-1-cyclohexene 0.6 mol% 1-chlorocyclohexene 11.7 mol%

[0031]

Example 3 11.25 g (625 mmol) of water and 1-methyl-2 were added to a 50 ml Hastelloy autoclave.
-11.25 g (113.5 mmol) of pyrrolidinone,
After charging 4.8 g (83 mmol) of potassium hydroxide and raising the temperature of the autoclave to 180 ° C.,
10.53 g of dichlorocyclohexane (68.8 mmol
l) was added dropwise at a rate of 1 ml / min with a pump and stirred for 2 hours. After completion of the reaction, the reaction mixture was cooled to room temperature to remove precipitated sodium chloride. When the filtrate was analyzed by gas chromatography, the conversion of 1,2-dichlorocyclohexane was 46%. The selectivities of the obtained reactants are as follows. 1,3-cyclohexadiene 87.3 mol% 1,4-cyclohexadiene 0.2 mol% cyclohexene 0.9 mol% benzene 1.5 mol% 3-hydroxy-1-cyclohexene 4.1 mol% 2,2′-dicyclohexenyl ether 1.1 mol% 1-chlorocyclohexene 5.0 mol%

[0032]

Example 4 Hexadecyltri-n as a phase transfer catalyst
-Butylphosphonium bromide 0.45 g (0.89
The same experiment as in Example 3 was performed except that (mmol) was added. After the completion of the reaction, the filtrate was analyzed by gas chromatography to find that the conversion of 1,2-dichlorocyclohexane was 60.0%. The selectivities of the obtained reactants are as follows. 1,3-cyclohexadiene 87.2 mol% 1,4-cyclohexadiene 0.1 mol% cyclohexene 0.3 mol% benzene 1.6 mol% 3-hydroxy-1-cyclohexene 5.2 mol% 2,2′-dicyclohexenyl ether 0.8 mol% 1-chlorocyclohexene 4.8 mol%

[0033]

Example 5 11.25 g (625 mmol) of water and 1-methyl-2 were placed in a 50 ml Hastelloy autoclave.
-11.25 g (113.5 mmol) of pyrrolidinone,
After charging 6.05 g (151.3 mmol) of sodium hydroxide and raising the temperature of the autoclave to 180 ° C, 8.57 g (56) of 1,2-dichlorocyclohexane was added.
mmol) and 3.27 g of 3-chlorocyclohexene (2
8 mmol) was dropped by a pump at a rate of 1 ml / min and stirred for 4 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and the precipitated sodium chloride was removed by filtration. When the filtrate was analyzed by gas chromatography,
The combined conversion of 1,2-dichlorocyclohexane and 3-chlorocyclohexene was almost 100%. The selectivities of the obtained reactants are as follows. 1,3-cyclohexadiene 85.0 mol% 1,4-cyclohexadiene 0.1 mol% cyclohexene 0.5 mol% benzene 1.6 mol% 3-hydroxy-1-cyclohexene 7.2 mol% 2,2′-dicyclohexenyl ether 2.8 mol% 1-chlorocyclohexene 2.8 mol%

[0034]

EXAMPLE 6 11.25 g (625 mmol) of water and 1-methyl-2 were placed in a 50 ml Hastelloy autoclave.
-11.25 g (113.5 mmol) of pyrrolidinone,
After charging 8.26 g (203 mmol) of sodium hydroxide and raising the temperature of the autoclave to 180 ° C,
12.39 g of 1,2-dichlorocyclooctane (68.
8 mmol) was added by a pump at a rate of 1 ml / min, and the mixture was stirred for 4 hours. After completion of the reaction, the reaction mixture was cooled to room temperature to remove precipitated sodium chloride. When the filtrate was analyzed by gas chromatography, the conversion of 1,2-dichlorocyclohexane was 100%. The selectivities of the obtained reactants are as follows. 1,3-cyclooctadiene 83.6 mol% 3-hydroxy-1-cyclooctene 10.0 mol% 1-chlorocyclooctene 6.4 mol%

[0035]

Comparative Example 1 In a 50 ml autoclave made of Hastelloy, 10.53 g of 1,2-dichlorocyclohexane (6.
8.8 mmol), 21.25 g of water (1181 mmol)
l), 8.26 g (203 mmol) of sodium hydroxide
And the temperature of the autoclave was raised to 180 ° C., followed by stirring for 4 hours. After completion of the reaction, the mixture was cooled to room temperature, but no salt was precipitated, and the mixture remained separated into two layers.
When the reaction solution was analyzed by gas chromatography, 1,2-dichlorocyclohexane was hardly converted.

[0036]

Comparative Example 2 11.25 g (127.7 mmol) of 1,4-dioxane was used instead of 1-methyl-2-pyrrolidinone.
An experiment similar to that of Example 4 was performed except that l) was used. After completion of the reaction, the mixture was cooled to room temperature, but no salt was precipitated, and the mixture remained separated into two layers. When the reaction solution was analyzed by gas chromatography, 1,2-dichlorocyclohexane was hardly converted.

[0037]

Comparative Example 3 10.0 g (556 mmol) of water and 1-methyl-2- were placed in a 50 ml Hastelloy autoclave.
After charging 11.25 g (113.5 mmol) of pyrrolidinone and 8.26 g (203 mmol) of sodium hydroxide, raising the temperature of the autoclave to 150 ° C.,
10.53 g of 1,2-dichlorocyclohexane (68.
8 mmol) was added dropwise at a rate of 1 ml / min using a liquid chromatography pump, and the mixture was stirred for 4 hours. The gauge pressure at this time was 2.5 atm. After completion of the reaction, the reaction mixture was cooled to room temperature to remove precipitated sodium chloride. When the filtrate was analyzed by gas chromatography, the conversion of 1,2-dichlorocyclohexane was 100%. The selectivities of the obtained reactants are as follows. 1,3-cyclohexadiene 5.1 mol% cyclohexene 0.4 mol% benzene 1.6 mol% 3-hydroxy-1-cyclohexene 89.1 mol% 2,2′-dicyclohexenyl ether 2.1 mol% 1-chlorocyclohexene 1. 7mol%

[0038]

Comparative Example 4 100 ml with a Dimroth reflux tube
6.89 g (45 mmol) of 1,2-dichlorocyclohexane, 15 g (151.3 mmol) of 1-methyl-2-pyrrolidinone, and 3.6 g (90 mmol) of sodium hydroxide are placed in a three-necked flask at 180 ° C. for 2 hours. Reacted. After cooling to room temperature, the precipitated sodium chloride was filtered. When the reaction filtrate was measured by gas chromatography, the conversion of 1,2-dichlorocyclohexane was almost 100%. The water content after the reaction was measured with a moisture meter (MOISTUREMETER manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) and found to be 3.6% by weight. The selectivities of the obtained reactants are as follows. 1,3-cyclohexadiene 43.8 mol% 1,4-cyclohexadiene 10.9 mol% benzene 1.0 mol% 1-chlorocyclohexene 25.4 mol% 3-hydroxy-1-cyclohexene 18.1 mol%

[0039]

According to the present invention, 1,3-cycloalkadiene having a very small amount of 1,4-cyclohexadiene can be easily produced in high yield.

Claims (8)

[Claims] 1. A method for obtaining a 1,3-cycloalkadiene by reacting a 1,2-dihalocycloalkane in the presence of a dipolar aprotic solvent and a base, wherein water is added to the reaction system; A process for producing 1,3-cycloalkadiene, characterized in that the reaction is carried out at a reaction temperature of at least 300C and not more than 300C. 2. The production of 1,3-cycloalkadiene according to claim 1, wherein the base is at least one selected from the group consisting of hydroxides and carbonates of alkali metals or alkaline earth metals. Law. 3. The method according to claim 1, wherein the 1,2-dihalocycloalkane is 1,2.
The method for producing 1,3-cycloalkadiene according to claim 1 or 2, wherein the method is -dichlorocyclohexane or 1,2-dibromocyclohexane. 4. The method for producing 1,3-cycloalkadiene according to claim 1, wherein the dipolar aprotic solvent is an amide compound and / or a sulfoxide compound. 5. The method according to claim 1, wherein the dipolar aprotic solvent is 1-methyl-2.
-Pyrrolidinone, characterized in that it is pyrrolidinone.
The method for producing 1,3-cycloalkadiene according to any one of the above. 6. The 1,2-dihalocycloalkane according to claim 1, wherein the 1,2-dihalocycloalkane is a 1,2-dihalocycloalkane containing a 3-halocycloalkene. A method for producing 3-cycloalkadiene. 7. The method according to claim 1, wherein the amount of water present in the reaction system is 0.1 times or more and 1000 times or less with respect to the 1,2-dihalocycloalkane. A method for producing 1,3-cycloalkadiene. 8. After the solution containing water, a dipolar aprotic solvent and a base is heated to 160 ° C. or more and 300 ° C. or less,
The 1,3 according to any one of claims 1 to 7, wherein a 1,2-dihalocycloalkane is added to the solution.
-A process for producing cycloalkadiene.