JPH01193232A - Method for aralkylating alkylbenzene - Google Patents

Abstract

PURPOSE:To obtain the aimed substance in high yield while suppressing side reaction, by using a solid acid as a catalyst and carrying out reaction while keeping styrene concentration in the reaction system at a specific value or below in aralkylating an alkylbenzene with styrenes. CONSTITUTION:An alkylbenzene having a 1-4C alkyl group is aralkylated with styrenes. In the process, a solid acid (e.g., silica alumina or activated clay) is used as a catalyst and reaction is carried out at 80-140 deg.C for 0.5-4hr while keeping the styrene concentration in the reaction system at <=0.1wt.% (preferably <=0.05wt.%) to provide alkyldiphenylethanes used as plasticizers, high-boiling solvents, electrical insulating oils, lubricating oils, etc. The amount of the catalyst used is preferably 0.1-5wt.% based on the total reaction solution. Furthermore, the concentration of the alkyldiphenylethane is preferably regulated to <=30wt.% for preventing addition of the styrenes.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention [Field of Industrial Application] The present invention relates to a method for aralkylating alkylbenzene with styrenes. The alkyldiphenylethanes obtained by the aralkylation method of the present invention have properties such as compatibility, heat resistance, lubricity, and electrical properties, and include plasticizers, high-boiling solvents, heat carriers, electrical insulating oils, It is a synthetic oil suitable for a wide range of uses such as hydraulic oil and lubricating oil.

[Conventional technology]

Conventionally, methods for aralkylating alkylbenzenes using styrenes include, for example, a method of reacting styrene with xylene or toluene using concentrated sulfuric acid as a catalyst, as proposed in JP-A No. 47-29351, and a method of reacting styrene with xylene or toluene using concentrated sulfuric acid as a catalyst;
A method of reacting styrene and alkylbenzene using a solid acid as a catalyst, as proposed in Japanese Patent No. 98, is known.

[Problem that the invention seeks to solve]

However, when carrying out an aralkylation reaction using styrenes industrially, the method using sulfuric acid requires a large amount of post-processing cost for neutralizing and washing with water to remove the catalyst after the reaction is completed, and also prevents corrosion of the equipment. There is a need to prevent environmental pollution caused by wastewater. On the other hand, in the method using a solid acid catalyst, aralkylated alkylbenzenes can be obtained in good yield in the reaction between styrenes and dialkylbenzenes, but in the reaction between styrenes and monoalkylbenzenes, the reactivity of styrenes towards monoalkylbenzenes is is lower than that of dialkylbenzene, aralkylated alkylbenzene cannot be obtained in good yield, and a large amount of dimers of styrenes such as indanes is produced. Since it is difficult to distill and separate the styrene dimer from aralkylated alkylbenzene, for example, when used as a solvent, solubility and fluidity deteriorate.

(2) Structure of the invention [Means for solving the problem] Therefore, as a result of intensive studies to suppress the formation of styrene dimers, the present inventors have found that the degree of styrene in the reaction system can be minimized. The present invention was completed based on the discovery that the formation of 7, fL/n digonate and alkylbenzene disterenides can be reduced by keeping the temperature low. That is, the present invention uses a solid acid as a catalyst in the reaction of aralkylating an alkylbenzene whose alkyl group has 1 to 4 carbon atoms with styrene, and the styrene concentration in the reaction system is reduced to 0.1.
The present invention relates to a method for aralkylating alkylbenzene, which is characterized in that the reaction is carried out while maintaining the reaction temperature to below a certain percentage.

(Detailed Description of the Invention) Alkylbenzenes having 1 to 4 carbon atoms in an alkyl group The alkylbenzenes having 1 to 4 carbon atoms in an alkyl group used in the present invention include toluene, ethylbenzene, globylbenzene, cumene, butylbenzene, etc. Examples include monoalkylbenzene.

Styrenes The styrenes used in the present invention are styrene, α-methylstyrene, and vinyltoluene. These can be used alone or in mixtures.

Further, it is necessary to maintain the # degree of styrene in the reaction system to 0.1% by weight or less, preferably 0.05% by weight or less of the total reaction solution.

Solid acid catalyst The solid acid catalyst used in the present invention includes oxides such as silica alumina, silica magnesia, and alumina boria;
Alternatively, clay minerals such as active saplings may be mentioned. The concentration of the catalyst is usually 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the total reaction solution! #%. 10 weight 1
There is no significant advantage in using it above %μ.

It is preferable to carry out the 31-fraction U arrangement reaction by charging alkylbenzene and a catalyst into a reactor, bringing the temperature to a predetermined temperature, and then sequentially adding styrenes little by little while stirring. At this time, it is also effective to dilute styrene with alkylbenzene and add it to prevent the styrene concentration from becoming locally high.

In addition, the concentration of the alkyldiphenylethane produced was 30
It is preferable that the weight is 1% or less. If the concentration of alkyldiphenylethane exceeds 30% by weight, it is not preferable because the styrene compound is added to the alkyldiphenylethane and the yield of alkyldiphenylethane decreases.

Reaction temperature The reaction temperature is usually TO-180°C, preferably 80°C.
The temperature is 0 to 140°C. Since the reaction is slow below 70°C, the dimerization reaction of styrene, which is a side reaction, increases relatively.
If it is more than 1800, side reactions such as disproportionation reactions will increase, which is not preferable.

Reaction Pressure There are no particular restrictions on the reaction pressure, and it is sufficient to maintain it in a liquid phase, but normal pressure or autogenous pressure at the reaction temperature is preferred.

Reaction time There is no particular restriction on the reaction time, as long as the styrene concentration can be maintained at 1% or less, and it is usually 0.2 to 8 hours, since unnecessarily long reaction times are industrially disadvantageous. Preferably it is 0.5 to 4 hours.

Next, the present invention will be explained with reference to Examples and Comparative Examples.

[Examples, etc.]

Example 1 477 tons of ethylbenzene, silica alumina (N633L manufactured by JGC Chemical ■, calcined at 800°C for 8 hours) 6
．． 5P was placed in an It flask with a stirrer and heated to 138°C. Under stirring, 52? A mixture of 539 grams of sterene and 539 grams of ethylbenzene was slowly added over 3.8 hours. The reaction temperature was maintained at 138t2°C. After the addition of styrene was completed, stirring was continued for an additional hour and the mixture was cooled. At this time, the styrene concentration during the reaction was 0.02 hours after the start of the reaction.
6%, and 0.045% after 3.8 hours. As a result of analysis by gas chromatography, the yield of ethyldiphenylethane based on styrene was 86%.

Example 2 Ethylbenzene 477 f, activated clay (Japanese activated clay)
G36 powder dried at 200°C for 2 hours) 6.
5 t was placed in a 1 t flask equipped with a stirrer and heated to 120°C. While stirring, a mixture of 52f styrene and 532 ethylbenzene was slowly added over 3 hours. The reaction temperature was maintained at 120t2°C. After the addition of styrene was completed, stirring was continued for an additional hour and the mixture was cooled. At this time, the styrene concentration during the reaction was 0.19% after 1.5 hours from the start of the reaction.
, 0.035% after 3 hours. As a result of analysis by gas chromatography, the yield of ethyldiphenylethane based on styrene was 87%.

Example 3 Ethylbenzene 477 f, activated white ± (Japan activated white clay ■
G36 powder dried at 200°C for 2 hours) 6.
5y was placed in a 1t flask equipped with a stirrer and heated to 120°C. While stirring, a mixture of 52t styrene and 53f ethylbenzene was slowly added over 119 minutes. The reaction temperature was maintained at 120t2°C. After adding styrene,
Stirring was continued for an additional hour and the mixture was cooled. At this time, the styrene concentration during the reaction was 0.5 hours after the start of the reaction.
25% and 0.035% after 1 hour. As a result of analysis by gas chromatography, the yield of ethyldiphenylethane based on styrene was 87%.

Example 4 Ethylbenzene (containing 100 ppm water) 477? ,
Activated clay (G36 powder manufactured by Japan Activated White Clay) at 200℃
(6.5 f) was placed in a flask equipped with a stirrer and heated to 120°C. While stirring, a mixture of 52t styrene and 53f ethylbenzene was slowly added over 1 hour. The reaction temperature was maintained at 120t2°C. After the addition of styrene was completed, stirring was continued for an additional hour and the mixture was cooled.

At this time, the lateral change of styrene during the reaction was 0.006% after 2 hours from the start of the reaction, and 0.021% after 4 hours.

Analysis by gas chromatography showed that the yield of ethyldiphenylethane based on styrene was 81%.

Comparative Example 1 Ethylbenzene 477 f, activated clay (Japan Active White ±■
2.29, which was prepared by drying G36 produced by M. Co., Ltd. at 200°C for 2 hours, was placed in a 1 t flask equipped with a stirrer and heated to 120°C.

While stirring, the mixture of 52f styrene and 53t ethylbenzene was gradually cooled down over 3.9 hours. At this time, the styrene concentration during the reaction was 0.51 2 hours after the start of the reaction.
%Met. As a result of gas chromatography analysis,
The yield of slethyldiphenylethane to styrene is 52
% tear vine.

Comparative Example 2 Ethylbenzene 477 f, activated white ± (Japanese activated white clay)
G36 powder dried at 200°C for 2 hours) 6.
5 t was placed in an IL flask equipped with a stirrer and heated to 120°C. While stirring, a mixture of 106F styrene and 104t ethylbenzene was slowly added over 6 hours. The reaction temperature was kept at 120±2C. After the addition of styrene was completed, stirring was continued for an additional hour and the mixture was cooled. At this time, 1 degree of styrene during the reaction is 0.03 after 3 hours from the start of the reaction.
5%, and 0.18% after 6 hours. As a result of analysis by gas chromatography, the yield of ethyldiphenylethane based on styrene was 57%.

(3) Effects of the Invention According to the present invention, by-products such as styrene dimers and alkylbenzene distyrenates can be largely suppressed, and the target aralkylated alkylbenzene can be advantageously produced in high yield. I can do it.

Patent applicant: Mitsubishi Yuka Co., Ltd. Agent: Patent Attorney Masahisa Nagatani Agent Patent Attorney Takaya Yamamoto

Claims (1)

[Claims] (1) In the reaction of aralkylating an alkylbenzene whose alkyl group has 1 to 4 carbon atoms with styrene, a solid acid is used as a catalyst, and the concentration of styrene in the reaction system is 0.1% by weight of the total reaction solution. A method for aralkylating alkylbenzene, characterized in that the reaction is carried out while maintaining the following: