RU1826964C - Method of synthesis of diethylbenzene and benzene isomers mixture - Google Patents

Abstract

The inventive products are a mixture of isomers of diethylbenzene (DEB) CioHi4, benzene SbNb. The reagent is ethylbenzene (EB). Conditions: elevated temperature, e.g. 120 ° C. Catalytic complex: May 20. % ethylbenzene May 80. % and water 2% of. After the process of disproportionation of EB, the reaction mass is treated with benzene at 40-50 ° C for 1-1.5 hours. Then, the catalytic complex is separated from the reaction products and separated by distillation. To carry out the transalkylation, n-DEB is taken in an amount of 3-5 May. % per reaction mass. For the simultaneous transalkylation of p-DEB and the purification of benzene from thiophene impurities and unsaturated compounds, benzene is taken in the amount in the calculation based on the weight ratio of the reaction mass of the disproportionation process; benzene 1: (0.5-1). 2 s.p. f-ly, t tab.

Description

The invention relates to organic chemistry, in particular to the production of a hydrocarbon from hydrocarbons with a six-membered aromatic core, and in particular to a method for producing diethylbenzene used for the synthesis of ion-exchange resins and benzene, which is widely used in organic synthesis.

The purpose of the invention is to reduce the content of paraisomer in a mixture of diethylbenzene isomers.

The goal is achieved in that in the method for producing a mixture of diethylbenzene and benzene isomers by disproportionation of ethylbenzene at elevated temperature in the presence of a catalytic complex based on aluminum chloride, comprising separating the catalytic complex from the reaction products and separating them by distillation, before separation

of the catalytic complex, the reaction mass of the disproportionation process is subjected to benzene treatment at 40-60 ° C for 1-1.5 hours.

To carry out the process, benzene is taken in an amount of 3-5 May. % per disproportionation reaction mass.

In order to increase the efficiency of the use of the catalytic complex and increase the productivity of the process on benzene, n-diethylbenzene is re-alkylated and benzene is purified from thiophene impurities and unsaturated compounds during disproportionation of the reaction mass with benzene, and benzene is taken in the amount based on the mass ratio of the reaction mass disproportionation: benzene 1: (0.5-1).

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The method provides in comparison with the known reduction in the content of paraisomer in diethylbenzene from May 31-35 to May 27-29. % and an increase in benzene productivity by 4-5 times.

The invention is illustrated by the following examples.

Example 1. Diethylbenzene and benzene are obtained in the presence of a catalytic complex based on (May 20,%), ethylbenzene (May 80,%) and water (2% of the mass of ALS). 97 kg of dried ethylbenzene and 3 kg of the catalytic complex are fed into the reactor and the disproportionation of ethylbenzene is carried out at 120 ° C for 15 minutes. The resulting reaction mass (100 kg) containing May. %: 16.2 benzene; 54 ethylbenzene; 27.3 diethylbenzene (including methadiethylbenzene 63.2, n-radioethylbenzene 33, orthodiethylbenzene 3.8, 2.5 polyalkylbenzenes, cooled to 40 ° C, mixed with 5 kg of benzene and re-alkylated for 1 hour

Get the reaction mass containing May. %: 18.6 benzene; 53.9 ethylbenzene; 25.2 diethylbenzene (including methadiethylbenzene 66.2; para-diethylbenzene 29.8, orthodiethylbenzene 4); 2.3 polyalkylbenzenes.

The reaction mass is freed from the catalyst by aqueous and alkaline washing, and then subjected to rectification.

In Examples 2-5, transalkylation of p-diethylbenzene during processing of the reaction mass with disproportionation with benzene is carried out analogously to Example 1, but with a change in temperature and time of the process. A sufficient amount of benzene is added to give rise to a re-alkylation reaction, resulting in the production of diethylbenzene with a paraisomer content of May 27-29. % This amount corresponds to a ten-fold excess of stoichiometric and amounts to 3-5 wt.% Per disproportionation reaction mass.

The results of the experiments are shown in the table.

How. It can be seen from the table that a temperature below 40 ° C and a time of less than 1 h are insufficient for the transalkylation process to occur, and at temperatures above 60 ° C and a reaction time of more than 1.5 hours, methadiethylbenzene also enter into the alkylation reaction with benzene, therefore, under these conditions x there is no improvement in the quality of diethylbenzene.

The process of purifying benzene from thiophene impurities and unsaturated compounds is illustrated by examples 6 and 7. Number

of the benzene to be purified is determined taking into account the purified ability of the catalyst contained in the disproportionation reaction mass. The optimum amount of benzene is expressed in a mass ratio to the disproportionation reaction mass (0.5-1): 1. The amount of benzene in more than 1: 1 ratio per disproportionation reaction mass leads to a decrease in the yield of diethylbenzene.

Example 6.100 kg of the reaction mass of the disproportionation of ethylbenzene, the composition of which is similar to Example 1, the electrical conductivity of the catalytic complex 6, is treated with benzene in an amount of 100 kg at 50 ° C for 1 h. Benzene quality: crystallization temperature 5.3 ° C

Sulfuric acid coloring in reference numbers 0.1

thiophene content 0.0005% 5 Get the reaction mass containing, may. %: 57.4 benzene; 28.7 ethylbenzene; 12.8 diethylbenzene (including methadiethylbenzene 67.7, paradiethylbenzene 28.3; orthodiethylbenzene 4) 1.1 polyal 0 kilobenzenes.

The electrical conductivity of the return catalyst is 6.75 Ohm cm. Benzene quality: crystallization temperature 5,4 ° C

sulfuric acid stain in reference scale numbers 0.04

thiophene content 0.0000057 0 Example. The process is carried out analogously to example 6, only benzene is taken in an amount of 50 kg for processing the reaction mixture. Get the reaction mass containing May. %: 42.8 benzene; 38.6 5 ethylbenzene; 16.9 diethylbenzene (including methadiztylbenzene 68.05, para-diethyl: benzene 27.8, orthodiethylbenzene 4.15); 1.7 prolalkylbenzenes.

The electrical conductivity of the return cat- 0. lisers ,. Benzene quality: crystallization temperature: 5.4 ° С

5 sulfuric acid stain in exemplary rooms

Scale 0.04

Claims (3)

thiophene content 0.0000089 Formula of the invention 1. A method for producing a mixture of diethylbenzene and benzene isomers by disproportionation of ethylbenzene at an elevated temperature in the presence of a catalytic complex based on aluminum chloride, comprising separating the catalytic complex from the reaction products and separating them by distillation, characterized in that, in order to reduce the content of the paraisomer in the mixture of diethylbenzene isomers, before the separation of the catalytic complex, the reaction mass of the disproportionation process processing with benzene at a temperature of 40-60 ° C for 1 -1.5 hours. 2. The method according to p. 1, characterized in that for the transalkylation of p-diethylbeisole in the processing of benzo scrap metal is taken in an amount of 3-5 wt.% per reaction mass of the disproportionation process. 3. The method according to p. 1, characterized in that, in order to increase the efficiency of the use of the catalytic complex and increase the productivity of the process on benzene, simultaneously re-alkylation of p-diethylbenzene and purification of benzene from thiophene impurities and unsaturated compounds when processing the reaction mass with benzene the disproportionation process, wherein benzene is taken in an amount based on the weight ratio of the reaction mass of the disproportionation process: benzene-1: (0,).