JPH0639424B2 - Method for producing tetraethylbenzene - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing tetraethylbenzene.
Tetraethylbenzene is useful as a raw material for producing benzene polycarboxylic acids and vinylbenzene, as well as a solvent and a heat medium.

[Conventional technology]

Tetraethylbenzene is obtained by ethylating benzene with an ethylating agent such as ethylene, but a method suitable for industrial production has not been reported. Alkylation such as ethylation proceeds in the presence of a Friedel-Crafts catalyst (Japanese Patent Publication No. 52-12,178, JP-A No. 61-6).
5,827), it is difficult to selectively produce tetraethylbenzene having four ethyl groups as compared with one having one ethyl group.

In addition, ethylbenzene is produced in large quantities as a styrene raw material, and at this time polyethylbenzene mainly composed of diethylbenzene is produced as a by-product, which is returned to the transalkylation step or discharged as residual oil or the like.

In addition, a method for producing tetraalkylbenzene by alkylating xylene with propylene or butene (Japanese Patent Publication No.
-12,178, Japanese Patent Publication No. 50-10,290, JP-A-48-72,130,
JP-A-48-19,526, JP-A-48-85,540, JP-A-49-35,
339), a method for producing tetraalkylbenzene by alkylating pseudocumene or mesitylene with propylene (Japanese Patent Publication No. 52-3369), and the like,
The raw material and the target substance are different from these methods. Further, the production of ethylbenzene using a solid acid catalyst is known from Japanese Patent Publication Nos. 60-7,603 and 60-21,571.

[Problems to be Solved by the Invention]

An object of the present invention is to provide a method for producing tetraethylbenzene industrially advantageously. Another object is to selectively produce tetraethylbenzene in a high yield.

[Means for Solving the Problems]

In the present invention, benzene and ethylene are reacted in the presence of a solid acid catalyst to obtain a reaction product containing ethylbenzene, diethylbenzene and triethylbenzene, and the reaction product is mainly composed of ethylbenzene, diethylbenzene and triethylbenzene. This is a method for producing tetraethylbenzene, in which a fraction is separated, a diethylbenzene fraction is sent to a step of transalkylating with benzene, and a triethylbenzene fraction is reacted with ethylene in the presence of a solid acid catalyst to form tetraethylbenzene.

In the present invention, a solid acid catalyst is used for the reaction between ethylene and benzene. That is, the solid acid catalyst has a higher production rate of polyethylbenzene such as diethylbenzene and triethylbenzene than the aluminum chloride catalyst usually used for the production of ethylbenzene, and its effective utilization is required.
Of course, if this is transalkylated with benzene, it can be converted into ethylbenzene, but an increase in the amount of recycling can not ignore the cost increase such as utility cost and fixed cost. As the solid acid catalyst, the X or Y type zeolite as described in the above-mentioned publication, the zeolite such as ZSM-5 type zeolite and mordenite, silica / these
Zeolites with modified alumina ratio, various zeolites such as zeolites modified with metals, etc.,
Silica-alumina and the like.

The reaction between benzene and ethylene can be carried out under the conditions for producing ordinary ethylbenzene, but it is preferable to carry out the reaction at 1.1 to 1.5 times the optimum diethylbenzene / ethylbenzene molar ratio at that time. That is, in the production of ethylbenzene, the yield of ethylbenzene is set to the maximum and the by-product of the non-reusable by-product is set to the minimum, and the conditions can be almost adopted in the present invention. However, in order to increase the yield of triethylbenzene, it is preferable to allow the ethylation to proceed a little excessively. For that purpose, increase the ethylene / benzene molar ratio,
The reaction temperature is raised, the contact time is lengthened, and the reaction rate of benzene is set high. Such conditions are as follows: ethylene / benzene molar ratio 1-0.05, 120-
400 ℃, normal pressure ~ 200kg / cm ² · G, LHSV 0.1-20 / h
You can choose from a range of r.

The products obtained by this reaction mainly consist of unreacted benzene and ethylbenzene, but since they contain polyethylbenzene such as diethylbenzene and triethylbenzene and by-products such as xylene, they are separated by distillation. To obtain respective fractions mainly containing benzene, ethylbenzene, diethylbenzene, triethylbenzene and the like. Then, the benzene fraction is returned to the reaction step, the ethylbenzene fraction is recovered as a product, the diethylbenzene fraction is sent to the transalkylation step, and the triethylbenzene fraction is sent to the tetraethylbenzene production step. Other,
When the tetraethylbenzene fraction and pentaethylbenzene fraction are collected, the former may be collected as tetraethylbenzene, and the latter may be sent to the transalkylation process or the tetraethylbenzene production process. It is desirable to collect other than the raw material or send it to the transalkylation process or the tetraethylbenzene production process.

The transalkylation step is a step of reacting diethylbenzene with benzene to give ethylbenzene, which can be carried out at the same time as the reaction of the benzene with ethylene or can be carried out in another reactor, but is preferably a solid acid. Performed in separate reactor with catalyst.

The triethylbenzene fraction is sent to the tetraethylbenzene production process and reacted with ethylene in the presence of a solid acid catalyst. As the solid acid catalyst, the same ones as described above can be used, and the reaction temperature and the like are almost the same.
It is also the same that transethylation is preferably carried out with the blowing of ethylene stopped. The ethylene / triethylbenzene molar ratio is preferably in the range of 0.05 to 1.5. When the reaction is carried out continuously, a low molar ratio of less than 0.8 is used. It is preferable to employ a high molar ratio. The reaction product obtained in this step is mainly composed of tetraethylbenzene and triethylbenzene, but since it contains ethylbenzene, pentaethylbenzene, etc., it is separated by distillation, and the tetraethylbenzene fraction is recovered as a product, and other fractions are as described above. Return to the same process. Since tetraethylbenzene consists of two types of isomers, if necessary, it may be separated by means such as crystallization,
It is desirable to return the isomer which is not the target component to the tetraethylbenzene production process to cause isomerization.

〔Example〕

Examples of the present invention will be shown below. In addition, part and% represent a weight part and weight%.

Example 1 A reaction product obtained by reacting benzene and ethylene in the presence of a Y-type zeolite catalyst (ethylbenzene: 14.0%,
Diethylbenzene: 4.4%, Triethylbenzene: 1.1%,
Tetraethylbenzene: 0.3%, benzene: 80%) was distilled to obtain a benzene fraction, an ethylbenzene fraction, a triethylbenzene fraction, a tetraethylbenzene fraction and a high boiling fraction.

The benzene fraction is returned to the reaction step, the ethylbenzene fraction is recovered as a product, and the diethylbenzene fraction is sent to the transalkylation step using a Y-type zeolite catalyst,
The triethylbenzene fraction was sent to the tetraethylbenzene production process, and the tetraethylbenzene fraction was recovered as a product.

The triethylbenzene fraction was reacted with about 1.2 times mol of ethylene in the presence of the Y-type zeolite catalyst to produce tetraethylbenzene. Reaction temperature 300 ℃, reaction time 1
When ethylation was carried out under the conditions of hr, catalyst amount 15%, pressure 20 kg / cm ² · G, triethylbenzene 27%, tetraethylbenzene 40%, pentaethylbenzene 18%, hexaethylbenzene 2%, then ethylene feed was stopped. When the above temperature and pressure were maintained for 5 hours for transethylation, products of 22% triethylbenzene, 58% tetraethylbenzene and 2% pentaethylbenzene were obtained. This product was distilled to obtain a triethylbenzene fraction and a tetraethylbenzene fraction, the former was returned to the tetraethylbenzene production step, and the tetraethylbenzene fraction was recovered as a product. In tetraethylbenzene
The ratio of the 1,2,4,5-body to the 1,2,3,5-body is 55:45, and the 1,2,4,5-body separated by crystallization is recovered as a product, and the others are The process was returned to the tetraethylbenzene production process.

〔The invention's effect〕

According to the production method of the present invention, tetraethylbenzene can be produced industrially advantageously and in high yield, and both ethylbenzene and tetraethylbenzene can be produced efficiently.

Claims (2)

[Claims] 1. A reaction product containing ethylbenzene, diethylbenzene and triethylbenzene is obtained by reacting benzene and ethylene in the presence of a solid acid catalyst, and ethylbenzene, diethylbenzene and triethylbenzene are mainly contained in the reaction product obtained. The distillate is separated and the diethylbenzene fraction is sent to the step of transalkylating with benzene.The triethylbenzene fraction is reacted with ethylene in the presence of a solid acid catalyst to form tetraethylbenzene, which is characterized by Production method. 2. An optimum diethylbenzene / ethylbenzene molar ratio of 1.1 for the purpose of producing ethylbenzene.
The method for producing tetraethylbenzene according to claim 1, wherein benzene and ethylene are reacted under a condition of about 1.5 times.