JP4367998B2 - Process for producing 1,3-cycloalkadiene - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing 1,3-cycloalkadiene, which is an alicyclic conjugated diene. In particular, the present invention relates to a method for synthesizing 1,3-cyclohexadiene obtained by dehydrochlorinating 1,2-dichlorocyclohexane.
[0002]
[Prior art]
In recent years, 1,3-cyclohexadiene is known to produce a highly heat-resistant and highly rigid polymer by living anionic polymerization, and is an industrially important monomer.
In obtaining a highly polymerized product from 1,3-cyclohexadiene, it is known that polymerization does not hinder even if cyclohexene, benzene, or methylcyclopentene is contained as impurities (Japanese Patent Laid-Open No. 7-196737). However, when 1,4-cyclohexadiene, which is an isomer of 1,3-cyclohexadiene, is contained as an impurity, polymerization does not proceed smoothly, and only a low molecular weight product is obtained, or polymerization does not proceed at all. [For example, Polym. Prepr. (Am. Chem. Soc. Div. Poym. Chem.) 12, p. 402 (1971)]. As a result of studies by the present inventors, in order to obtain a desired high molecular weight product, the content of 1,4-cyclohexadiene needs to be at least 2% or less.
[0003]
Various methods have been proposed for synthesizing 1,3-cyclohexadiene. The synthesis of 1,2-dibromocyclohexane by dehydrohalogenation has been reported. As the dehydrobromination reaction from 1,2-dibromocyclohexane, 1,3-cyclohexadiene is obtained from the reaction of 1,2-dibromocyclohexane and potassium hydroxide in triethylene glycol (Organikum, 5. Aufll). , S. 226, VED Deutscher Verlag der Wissenschaffen, Berlin 1965). However, in this method, a large amount of benzene and 1,4-cyclohexadiene are by-produced in addition to 1,3-cyclohexadiene, 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 are azeotropic, making it difficult to fractionate by distillation.
[0004]
In addition, 1,3-cyclohexadiene was obtained in 82% yield by heating 1,2-dibromocyclohexane in a hexamethylphosphoric triamide at 160 ° C. using a mixture of lithium chloride and lithium carbonate. [J. Org. Chem. 49, 2650 (1984)]. However, when the present inventors reacted under the conditions described in this document, 1,3-cyclohexadiene was obtained in a yield of 47%. At the same time, cyclohexene was 30% and benzene was 23%. A lot of creatures were generated. Since cyclohexene and benzene have boiling points close to 1,3-cyclohexadiene, it is difficult to separate them by distillation. For this reason, high purity 1,3-cyclohexadiene could not be obtained. As estimated by the present inventors, the results of the reaction described in this document are achieved only under special reaction conditions, and it is difficult to stably obtain a high yield.
[0005]
In addition to these methods, various methods for synthesizing 1,3-cyclohexadiene using 1,2-dibromocyclohexane as a raw material have been proposed.
For example, Zupanic et al. Report that 1,3-cyclohexadiene can be obtained from 1,2-dibromocyclohexane in a yield of 57%. In this report, reacting 1,2-dibromocyclohexane with sodium in methanol yielded 2.2% 1,3-cyclohexadiene and 70% 3-methoxycyclohexene, and further converted 3-methoxycyclohexene into Reaction with 85% phosphoric acid in triethylene glycol yields 1,3-cyclohexadiene in 82% yield [Chem. Ber. , 100, P.I. 1764 (1967)].
[0006]
As a similar method, it is reported that 1,2-dibromocyclohexane and sodium ethoxide are reacted to synthesize 3-ethoxycyclohexene, and then high-purity 1,3-cyclohexadiene is obtained by dealcoholization reaction. [Mitt. Schles. Kohlenforsh. -Inst. Kaiser-Wilheim-Ges. 2, 97 (1925), C.I. 1926, 2343].
However, when 1,2-dibromocyclohexane is used as a raw material and reacted with lithium salt or sodium salt, a large amount of lithium bromide or sodium bromide is produced as a by-product, and the waste containing this organic matter A large amount of energy is consumed for processing, and it is difficult to be an industrial scale manufacturing method. Therefore, there is a need for a method for producing 1,3-cyclohexadiene having a high yield and high purity from 1,2-dichlorocyclohexane that can significantly reduce the amount of waste from bromide.
[0007]
It is known that 1,2-dichlorocyclohexane can be obtained by chlorinating cyclohexene.
For example, when Poutsma et al. Chlorinate cyclohexene at 25 ° C. in the dark, 3-chlorocyclohexene, 1,2-dichlorocyclohexane and 4-chlorocyclohexene were in a ratio of 1.00: 1.95: 0.60. It is reported to generate. Thus, 1,2-dichlorocyclohexane can be easily obtained as a main product by chlorination of cyclohexene [J. Am. Chem. Soc. 87 (10) P.A. 2161 (1965)].
[0008]
As a method for synthesizing 1,3-cyclohexadiene from 1,2-dichlorocyclohexane, a high yield is obtained in one step by reacting in a solution or suspension of sodium hydroxide and polyglycol at 150 to 170 ° C. It is reported that cyclohexadiene is obtained at a high rate (DE 1090202). However, nothing is described about the purity of 1,3-cyclohexadiene, and the by-product amount of 1,4-cyclohexadiene is unknown. According to the results of experiments conducted by the present inventors under the conditions described in this patent document, the yield of cyclohexadiene increases when the reaction temperature is high or the molecular weight of the polyglycol increases. The content of cyclohexadiene tends to increase, and even when various reaction conditions are changed, the content of 1,4-cyclohexadiene in 1,3-cyclohexadiene is at least over 2%. It was unsuitable as high purity 1,3-cyclohexadiene required by the inventors.
As described above, a production method for obtaining 1,3-cyclohexadiene with high yield and purity from 1,2-dichlorocyclohexane has not been reported.
[0009]
[Problems to be solved by the invention]
An object of the present invention is a process for producing 1,3-cyclohexadiene from 1,2-dichlorocyclohexane capable of reducing the amount of waste, and there is very little by-production of 1,4-cyclohexadiene, which is industrial. And a process for producing high purity 1,3-cyclohexadiene from 1,2-dichlorocyclohexane.
[0010]
[Means for Solving the Problems]
As a result of intensive studies by the present inventors to solve the above problems, a basic compound containing at least one metal carbonate and / or metal bicarbonate from 1,2-dichlorocycloalkane in an aprotic polar solvent It was found that high purity 1,3-cycloalkadiene with very little by-product of 1,4-cycloalkadiene can be easily produced by dehydrochlorination using is there.
[0011]
That is, the present invention
[1] In a method for producing 1,3-cycloalkadiene from 1,2-dichlorocycloalkane, N-methylpyrrolidinone, hexamethylphosphoric triamide, N, N-dimethylacetamide, N, N-diethyl Dehydrochlorination using a basic compound containing at least one metal carbonate and / or metal bicarbonate in at least one aprotic polar solvent selected from acetamide, o-dichlorobenzene, and diphenyl ether A method for producing 1,3-cycloalkadiene,
[2] The method for producing 1,3-cycloalkadiene according to [1], wherein the metal carbonate and / or metal bicarbonate is an alkaline earth metal carbonate,
[3] The method for producing 1,3-cycloalkadiene according to [1] or [2], wherein the metal carbonate and / or metal bicarbonate is calcium carbonate,
[4] The basic compound containing at least one metal carbonate and / or metal hydrogen carbonate is an alkali metal metal carbonate and / or metal hydrogen carbonate, and uses lithium chloride. [1] A method for producing 1,3-cycloalkadiene according to any one of [3],
[5] The method for producing 1,3-cycloalkadiene according to any one of [1] to [4], wherein 1,2-dichlorocycloalkane is 1,2-dichlorocyclohexane,
It is.
[0012]
Hereinafter, the present invention will be described in detail.
The 1,2-dichlorocycloalkane in the present invention is preferably a 5- to 10-membered 1,2-dichlorocycloalkane, more preferably 1,2-dichlorocyclohexane. 1,2-Dichlorocycloalkane has cis and trans isomers as isomers, and either isomer may be used as a raw material or a mixture may be used as a raw material. Further, 1,2-dichlorocycloalkane in the present invention may contain 3-chlorocycloalkene. It has been found that 3-chlorocycloalkene can be obtained by co-production with 1,2-dichlorocycloalkane by chlorinating cycloalkene. The amount of 3-chlorocycloalkene is from 0 mol% to 95 mol%. When 4-chlorocycloalkene reacts by the production method of the present invention, 1,4-cycloalkadiene is by-produced. For this reason, the content of 4-chlorocycloalkene relative to 1,2-dichlorocycloalkane is preferably 2 mol% or less, more preferably 1 mol% or less. Such 1,2-dichlorocycloalkene can be produced by various methods. For example, as described in the section of the prior art, a chlorination mixture obtained by chlorination of cycloalkene can be used for distillation or the like. It can be obtained by a purification method.
[0013]
The metal carbonate and / or metal hydrogen carbonate in the present invention is an alkali metal carbonate and / or an alkali metal hydrogen carbonate , an alkaline earth metal carbonate and / or an alkaline earth hydrogen carbonate, or a rare earth metal carbonate. Alkali metal bicarbonate. Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate. Examples of the alkaline earth metal carbonate include magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate. Examples of the salt include yttrium carbonate, lanthanum carbonate, cesium carbonate, neodymium carbonate, gadolinium carbonate, ytterbium carbonate, and lutetium carbonate. Examples of the alkali metal hydrogen carbonate include sodium hydrogen carbonate and potassium hydrogen carbonate. Among these metal carbonates and / or metal hydrogen carbonates, calcium carbonate is particularly preferable from the viewpoint of reaction rate. These metal carbonates and / or metal hydrogen carbonates are preferably anhydrous, but can also be used as hydrates. In addition, the metal carbonate and / or metal bicarbonate may be used alone or as a mixture of two or more.
[0014]
The amount of the metal carbonate and / or metal bicarbonate, carbonate ion based when dissociated, 1,2 5-fold mol 0.8 mol per mol of dichlorobenzene cycloalkane is rather preferable, further Preferably it is 1.0 times mole to 2.5 times mole. If the amount used is less than 0.8-fold mol, the reaction rate of 1,2-dichlorocycloalkane decreases and a satisfactory yield cannot be obtained, and even if it is used more than 5-fold mol, the reaction is accelerated. The effect is small and a large excess of base is wasted.
[0015]
Examples of the basic compound containing at least one metal carbonate and / or metal bicarbonate in the present invention include metal chlorides and metal hydroxides other than the metal carbonate and / or metal bicarbonate . Examples of the metal chloride include alkali metal chlorides such as lithium chloride, sodium chloride and potassium chloride, and alkaline earth metal chlorides such as magnesium chloride and calcium chloride. Examples of the metal hydroxide include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as magnesium hydroxide and calcium hydroxide, and aluminum hydroxide.
The amount of the metal carbonate and / or metal salt other than the metal hydrogen carbonate is preferably 0.1 to 5 times mol, more preferably 0.1 times mol to the metal carbonate (hydrogen) salt to be mixed. To 2 times mole.
[0016]
The dehydrochlorination reaction in the present invention is performed in a suspended state or a solution state using a reaction solvent. The reaction solvent is an aprotic polar solvent. A polar solvent containing a nitrogen atom is preferred. Examples of aprotic polar solvents include N-methylpyrrolidinone, hexamethylphosphoric triamide, N, N-dimethylacetamide, N, N-diethylacetamide, o-dichlorobenzene, diphenyl ether, and the like. Of these, N-methylpyrrolidinone and hexamethylphosphoric triamide are preferred. The amount of the solvent is 0.1 to 100 times the weight, preferably 0.1 to 10 times the weight of 1,2-dichlorocycloalkane. If the amount of the solvent is less than 0.1 times, the effect of the solvent is small and the reaction rate is slow, and if the amount of the solvent exceeds 100 times, the reaction proceeds rapidly, but the productivity decreases, which is not substantial.
[0017]
The reaction temperature in this invention is the range of 80 degreeC or more and 250 degrees C or less, Preferably it is the range of 100 degreeC or more and 200 degrees C or less. When the reaction temperature is less than 80 ° C, the progress of the reaction is slow.
The reaction pressure in the present invention is not particularly limited.
In the present invention, 1-chlorocyclohexene may be by-produced in addition to 1,3-cyclohexadiene, but this by-product has a large boiling point difference from 1,3-cyclohexadiene and can be easily obtained by a method such as distillation. 1,3-cyclohexadiene with high purity can be obtained.
The high purity 1,3-cyclohexadiene produced with the present invention and having a small amount of 1,4-cyclohexadiene can be polymerized by a known method (for example, WO94 / 28038) and has a high average molecular weight (1,3 -Cyclohexadiene) homopolymer can be obtained. Moreover, the copolymer containing a 1, 3- cyclohexadiene unit can be obtained by making it copolymerize with another monomer.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example etc., this invention is not limited at all by these Examples.
[Example 1]
To a 200 ml glass reactor equipped with a simple distillation device, thermometer and rotor, add 30 g (0.20 mol) 1,2-dichlorocyclohexane, 100 ml N-methylpyrrolidinone and 20 g (0.20 mol) calcium carbonate. It was. The reactor was immersed in an oil bath and the temperature inside the reactor was raised to 180 ° C., and then stirred for 2 hours while distilling low boiling components. As a result of analyzing the obtained fraction and the residue in the reactor by gas chromatography, 1,3-cyclohexadiene was obtained in a yield of 49 mol%. As a by-product, 1-chlorocyclohexene was obtained in a yield of 48 mol%, but 1,4-cyclohexadiene was sufficiently small as 0.5 mol% with respect to 1,3-cyclohexadiene. By purification by distillation, 6.8 g of 1,3-cyclohexadiene having a purity of 99.5% was obtained.
[0019]
[Example 2]
The calcium carbonate of Example 1 was changed to a mixture of 27.1 g (0.20 mol) of potassium carbonate and 8.3 g (0.20 mol) of lithium chloride, and N-methylpyrrolidinone was changed to 100 ml of hexamethylphosphoric triamide. The reaction was performed in the same manner as in Example 1 except that. As a result of analysis of the product, the yield of 1,3-cyclohexadiene was 50 mol%, the yield of 1-chlorocyclohexene was 47 mol%, and 1,4-cyclohexadiene was 0 with respect to 1,3-cyclohexadiene. It was 4 mol%. By purification by distillation, 6.9 g of 1,3-cyclohexadiene having a purity of 99.6% was obtained.
[0020]
[Example 3]
The reaction was carried out in the same manner as in Example 1 except that 1,2-dichlorocyclohexane in Example 1 was changed to 35 g (0.20 mol) of 1,2-dichlorocyclooctane. As a result of analysis of the product, the yield of 1,3-cyclooctadiene was 51 mol%, the yield of 1-chlorocyclooctene was 47 mol%, and 1,4-cyclooctadiene was 1,3-cyclooctadiene. It was 0.6 mol% with respect to this. By purification by distillation, 9.6 g of 1,3-cyclooctadiene having a purity of 99.3% was obtained.
[0021]
[Comparative Example 1]
The reaction was performed in the same manner as in Example 1 except that the calcium carbonate of Example 1 was changed to 7.8 g (0.20 mol) of sodium hydroxide. As a result of analysis of the product, the yield of 1,3-cyclohexadiene was 44 mol%. As by-products, 1-chlorocyclohexene was produced in a yield of 25 mol% and 3-hydroxycyclohexene was produced in a yield of 18 mol%, and 1,4-cyclohexadiene was 25 mol% based on 1,3-cyclohexadiene. . Distillation purification was attempted, but only 7.5 g of a mixture of 1,3-cyclohexadiene and 1,4-cyclohexadiene (molar ratio 76:24) was obtained, and high-purity 1,3-cyclohexadiene was obtained. There wasn't.
[0022]
[Comparative Example 2]
The reaction was performed in the same manner as in Example 1 except that the calcium carbonate of Example 1 was changed to 34.2 g (0.20 mol) of magnesium phosphate second trihydrate, but 1,2-dichlorocyclohexane was It was only recovered and the reaction did not proceed.
[0023]
[Comparative Example 3]
Using the reactor of Example 1, a mixture of 60 g (0.12 mol) of polyethylene glycol having an average molecular weight of 500, 22.5 g (0.40 mol) of potassium hydroxide and 20 g (0.13 mol) of 1,2-dichlorocyclohexane was used. The reaction was carried out in the same manner as in Example 1 using the raw materials. As a result of analysis of the product, the yield of 1,3-cyclohexadiene was 44 mol%. As a by-product, 3-hydroxycyclohexene was produced at 1.3 mol%, and 1,4-cyclohexadiene was 27 mol% based on 1,3-cyclohexadiene. Distillation purification was attempted, but only 5.3 g of a mixture of 1,3-cyclohexadiene and 1,4-cyclohexadiene (molar ratio 75:25) was obtained, and high-purity 1,3-cyclohexadiene was obtained. There wasn't.
[0024]
[Comparative Example 4]
Using the reaction apparatus of Example 1, a mixture of 60 g (0.57 mol) of diethylene glycol, 22.5 g (0.40 mol) of potassium hydroxide and 20 g (0.13 mol) of 1,2-dichlorocyclohexane was used as a raw material. The reaction was carried out in the same manner as in 1. As a result of analysis of the product, the yield of 1,3-cyclohexadiene was 40 mol%. As a by-product, 3-hydroxycyclohexene was produced at 1.8 mol%, and 1,4-cyclohexadiene was 25 mol% based on 1,3-cyclohexadiene. Although distillation purification was attempted, high-purity 1,3-cyclohexadiene was obtained only by obtaining 5.0 g of a mixture of 1,3-cyclohexadiene and 1,4-cyclohexadiene (molar ratio 77:23). There wasn't.
[0025]
【The invention's effect】
As described above, the content of 1,4-cyclohexadiene is extremely low by dehydrochlorinating the dichlorocycloalkane of the present invention using a metal carbonate (hydrogen) salt in an aprotic polar solvent. 3-Cycloalkadiene could be easily produced in high yield.

Claims (5)

In a process for producing 1,3-cycloalkadiene from 1,2-dichlorocycloalkane, N-methylpyrrolidinone, hexamethylphosphoric triamide, N, N-dimethylacetamide, N, N-diethylacetamide, o -Dehydrochlorination using a basic compound containing at least one metal carbonate and / or metal bicarbonate in at least one aprotic polar solvent selected from dichlorobenzene and diphenyl ether ; A method for producing 3-cycloalkadiene. The method for producing 1,3-cycloalkadiene according to claim 1, wherein the metal carbonate and / or metal hydrogen carbonate is an alkaline earth metal carbonate. The method for producing 1,3-cycloalkadiene according to claim 1 or 2, wherein the metal carbonate and / or metal bicarbonate is calcium carbonate. 2. The basic compound containing at least one metal carbonate and / or metal hydrogen carbonate is an alkali metal metal carbonate and / or metal hydrogen carbonate, and lithium chloride is used. The manufacturing method of the 1, 3- cycloalkadiene in any one of -3.   The method for producing 1,3-cycloalkadiene according to any one of claims 1 to 4, wherein the 1,2-dichlorocycloalkane is 1,2-dichlorocyclohexane.