JPS6183137A - Production of beta-alkyl-substituted naphthalene - Google Patents

Abstract

PURPOSE:To obtain the titled substance, in high selectivity, with little production of by-products having high boiling point, by the trans-alkylation reaction of a naphthalene compound with a polyalkylbenzene in the presence of an AlCl3 catalyst in a (cyclo)paraffin solvent at a specific temperature. CONSTITUTION:The objective substance can be produced by the trans-alkylation reaction of a naphthalene compound (e.g. naphthalene, alkylnaphthalene, etc.) with a polyalkylbenzene in the presence of an AlCl3 catalyst at 0-35 deg.C (prefer ably at normal temperature) to an extent to give a naththalene conversion of >=40wt% (preferably 40-60%). The amount of the catalyst is 0.05-0.4 mol per 1 mol of the naththalene compound, and the ca talyst may be used in the form of a complex with an aromatic hydrocarbon, nitromet hane, etc. When the naththalene compound is solid and is not sufficiently soluble in the polyalkylbenzene, the reaction is carried out in a solvent. USE:Raw material for the production of beta-naphthol, etc.

Description

Detailed Description of the Invention [Field of Industrial Application] This invention is directed to the production of β-alkyl-substituted naphthalene, which is useful as a raw material for producing β-fathol, which is useful as an intermediate raw material exclusively for pharmaceuticals, dyes, agricultural chemicals, and surfactants. Regarding the production method, in more detail, β
The present invention relates to a method for producing alkyl-substituted naphthalenes having an alkyl group at the -position.

(Prior Art) β-Alkyl UJi naphthalenes can be easily synthesized by reacting naphthalenes with olefins or alkylating agents such as alkyl halides in the presence of a Friedel-Craft catalyst. , along with the target β-alkyl-substituted naphthalene, its 57-mer α-alkyl-substituted naphthalene and trialkyl v1
Polyalkylated naphthalene or naphthalene polymers, etc., are frequently produced, making it difficult to selectively produce β-alkyl-substituted naphthalene.

Therefore, an alkylnaphthalene with a high M content of a β-substituted product is produced by a transalkylation reaction between naphthalene and polyalkylbenzene. l! A method has been proposed (Japanese Patent Publication No. 46-9576).

[Problem that the invention seeks to solve]

According to this method, β-alkyl-substituted naphthalene can be obtained in a relatively high proportion, but there is still room for improvement in terms of the yield of 2,6-dialkylnaphthalene or the production of high-boiling byproducts. .

The purpose of the present invention is to obtain β-alkyl-purchased naphthalene with high selectivity through a transalkylation reaction and to provide a method for producing β-alkyl-purchased naphthalene in which the production of high-boiling byproducts is significantly reduced. do.

[Means and effects for solving the problems] The present invention involves reacting naphthalenes and polyalkylbenzenes in the presence of an aluminum chloride catalyst at a reaction temperature of 0 to 35°C such that the naphthalene conversion rate is 40% by weight or more. This is a method for producing β-alkyl substituted naphthalene.

In the present invention, as the naphthalenes used as raw materials, in addition to naphthalene, at least one β
Examples include furkylnaphthalenes such as methylnaphthalenes which are not substituted at the - position. When 2.6-dialkylnaphthalene or 2.7-dialkylnaphthalene is the objective, naphthalene or β-methylnaphthalene is suitable as a raw material.

In addition, in the present invention, polyalkylbenzenes used as alkylating agents include durene, diethylbenzene, triethylbenzene, triisopropylbenzene, isopropylxylene dibutylbenzene, etc., but ethyl having a large number of carbon atoms in the alkyl group, Polyalkylbenzene having a propyl or butyl group has a fast reaction rate. The amount of polyalkylbenzene used is usually an equimolar amount to 10 times the amount of alkyl group per mole of naphthalene. Preferably, one alkyl group is introduced. In the case of introducing two alkyl groups, the amount is 1 to 8 times the molar amount, and when two alkyl groups are introduced, the amount is 3 to 10 times the molar amount.

Furthermore, the amount of the aluminum chloride catalyst used in the present invention is usually 0.01 to 0.0% based on naphthalenes.
It is 5 times the molar amount, preferably 0.05 to 0.4 times the molar amount. If the amount of this catalyst used is small, the reaction rate will be slow. In addition,
Aluminum chloride can also be used in the form of a complex with aromatic hydrocarbons, nitromethane, etc.

The method of the invention carries out the reaction in the liquid phase. Note that when the naphthalene is solid at the reaction temperature and does not dissolve sufficiently in the polyalkylbenzene, it is preferable to use a solvent. Suitable solvents include paraffins such as n-hexane and n-hebutane, or cycloparaffins such as cyclopentane, cyclohexane and decalin, which have a boiling point lower than that of naphthalenes.
In the method of the present invention, the reaction temperature must be 0 to 35°C, preferably room temperature. Increasing the reaction temperature reduces the selectivity of β-alkyl substituted naphthalenes, especially 26-dialkylnaphthalenes.

Further, the reaction time is 5 to 100 hours, preferably 10 to 100 hours.
50 hours, and the conversion rate of naphthalenes is 40% or more,
Preferably, the amount is 40 to 60%.

After the reaction is completed, the catalyst is separated and subjected to treatments such as water washing and alkali washing, and then charged into a distillation column and distilled and separated to obtain β-alkyl-substituted naphthalene.

(Example) Hereinafter, the method of the present invention will be specifically explained based on Examples.

Example 1 0.3 mol of naphthalene, 0.3 mol of triisopropylbenzene.
6 mol of aluminum chloride and O,0,3(l-l) were dissolved in 0.7 mol of cyclopentane, kept at O'C and stirred, followed by transalkylation reaction.

A small amount of the reaction mixture was taken out at regular intervals and subjected to compositional analysis to determine the naphthalene conversion rate and the yields of isopropylnaphthalene and diimpropylnaphthalene. The results are shown in Table 1.

In addition, the formation formula 11 of β-isopropylnaphthalene in isopropylnaphthalene has a naphthalene conversion rate of 13.7.
%, 40.8%, 58.3% and 600%, they were 92.3 mol%, 99.3 mol%, 99.4 mol% and 99.4 mol%, respectively.

In addition, the production ratio of 2,6-diitubrobylnaphthalene and 2,7-diitupropylnaphthalene in diisopropylnaphthalene is approximately 1:1 on average, and the amount of other disubstituted products is 6.0 mol%. It was before and after.

Example 2 A transalkylation reaction was carried out under the same conditions as in Example 1 above, except that the reaction temperature was 30° C. and cyclopentane was not used.

A small amount of the reaction mixture was extracted at regular intervals and subjected to compositional analysis. The results are shown in Table 2.

Further, the production of 2.1 times of β-isopropylnaphthalene in isopropylnaphthalene was approximately 99 mol% when the naphthalene conversion rate was 40% or more.

Further, the production ratio of 2,6-diitubropylnaphthalene and 2,7-diitubropylnaphthalene in diisopropylnaphthalene is 1:1 on average,
The content of other disubstituted products was around 10 mol%.

Example 3 0.7 mol of β-methylnaphthalene, 1 mol of diethylbenzene
．． 1 mole of aluminum chloride and 0.28 mole of aluminum chloride were dissolved in 0.62 mole of nitrobenzene, and the mixture was kept at 30° C. and continued stirring to perform a transalkylation reaction. The reaction results are shown in Table 3.

Comparative Example 1 A transalkylation reaction was carried out under the same conditions as in Example 2 above, except that the reaction temperature was 60°C.

A small amount of the reaction mixture was extracted at regular intervals and subjected to compositional analysis. The results are shown in Table 4.

Further, the production ratio of β-inpropylnaphthalene in isopropylnaphthalene was approximately 94 mol% when the naphthalene conversion rate was 30% or more.

Furthermore, the production ratio of 2,6-diitupropylnaphthalene and 2,7-diitupropylnaphthalene in diisopropylnaphthalene was 1:1, but other disubstituted products were 20 mol% Regenerated.

Table 1 Table 3 Table 2 Table 4 [Effects of the Invention] According to the present invention, β-alkyl-substituted naphthalene can be obtained with high selectivity, and in particular, 2,6-dialkylnaphthalene can be obtained with high selectivity. I can do it. Furthermore, the method of the present invention produces less polymer by-products, and provides a high utilization rate of naphthalenes if unreacted naphthalenes are recycled after the reaction is completed. Furthermore, in the method of the present invention, there is no need to particularly heat the reactor, so the reaction can be carried out efficiently using not only a tank reactor but also a pipe reactor or the like.

Claims (2)

[Claims] (1) β-alkyl substitution characterized by transalkylating naphthalenes and polyalkylbenzene in the presence of an aluminum chloride catalyst at a reaction humidity of 0 to 35°C such that the naphthalene reaction rate is 40% by weight or more. Method for producing naphthalene. (2) A method for producing β-alkyl-substituted naphthalene according to claim 1, in which naphthalenes and polyalkylbenzene are subjected to a transalkylation reaction in a paraffinic or cycloparaffinic solvent.