A kind of reaction method of benzene and methanol alkylation

Abstract

The invention belongs to the technical field of petrochemical industry catalysis, and provides a reaction method for benzene and methanol alkylation. The method specifically comprises the following steps: using a fixed bed reactor as a reaction device, and using a strip-type hydrogen ZSM-5 molecular sieve as a catalyst, wherein reaction conditions are as follows: the reaction temperature is 400 DEG C, the total mass space velocity is 2h<-1>, and the mole ratio of benzene to methanol is 2:1; and creating a micro-negative pressure state for a reaction system through a mechanical pump vacuumizingmethod, wherein the pressure is less than a normal pressure, and 0.03-0.07 MP preferably. The method is simple in operating system, easy to operate, and suitable for multiple catalysts, and a negative pressure degree of the system can be regulated according to an ethylbenzene limiting index. An alkylation reaction is simply and accurately controlled to be performed on the outer surface of the catalyst, the limitation of micropore diffusion is avoided, and the alkylation reaction can be performed at a lower temperature.

Description

technical field [0001] The invention belongs to the technical field of petrochemical catalysis and relates to a reaction method for the alkylation of benzene and methanol. Background technique [0002] Both toluene and mixed xylene are important raw materials for the production of paraxylene (PX), and paraxylene is an important aromatic hydrocarbon chemical raw material, which is mainly used to produce purified terephthalic acid (PTA) and then produce polyester. It is the leader of the polyester product chain. Toluene and mixed xylenes can be obtained from the alkylation reaction of benzene and methanol. With the increase of my country's methanol production and lower prices, it is of industrial significance to use methanol and benzene to produce toluene and xylene. However, the alkylation of benzene and methanol also produces impurity aromatics such as ethylbenzene, propylbenzene, methylethylbenzene, trimethylbenzene and tetramethylbenzene. Since the boiling points of eth...

AI Technical Summary

Problems solved by technology

It solves the problems in the prior art that the source of raw materials is single or the amount of methanol introduced is small, the reaction wastewater contains methanol, the single-pass conversion rate is low, and the methylation selectivity is low.