A kind of preparation method of high selectivity anti-carbon deposition benzene alkylation catalyst

Abstract

The invention belongs to the technical field of petrochemical engineering catalysts, and discloses a preparing method of a high-selectivity anti-carbon benzene alkylation catalyst. The preparing method comprises the steps of 1, selecting a high silica-alumina-ratio MFI zeolite molecular sieve to serve as a parent of the catalyst; 2, mixing acidized silicone grease hydrolysate with the high silica-alumina-ratio MFI zeolite molecular sieve to be subjected to extrusion forming, and then using an aqueous solution of ammonium hexafluorosilicate to treat the formed strip-shaped product; 3, using separating mother liquor which is obtained by using hydration heat to crystallize the high silica-alumina-ratio MFI zeolite molecular sieve to treat the formed strip-shaped product of the high silica-alumina-ratio MFI zeolite molecular sieve; 4, adopting an ion exchange method to convert the formed strip-shaped product of the high silica-alumina-ratio MFI zeolite molecular sieve which is treated by the mother liquor into a hydrogen-form alkylation catalyst. By means of the preparing method of the high-selectivity anti-carbon benzene alkylation catalyst, the mother liquor which is generated duringhydro-thermal synthesis of the high silica-alumina-ratio MFI zeolite molecular sieve is used for treating the formed strip-shaped catalyst, useful ingredients in the mother liquor are recycled, poresof the catalyst are unblocked, and the environmental pollution in the whole production chains of the alkylation catalyst is also reduced.

Description

technical field [0001] The invention belongs to the technical field of petrochemical catalysts, and relates to a preparation method of a benzene alkylation catalyst. Background technique [0002] The gas-phase alkylation of benzene, methanol and ethanol can be used to synthesize xylene and ethylbenzene respectively, the former can be used to produce p-xylene, and then produce terephthalic acid; the latter can be used for dehydrogenation to produce styrene, and then produce polyphenylene vinyl etc. Because water is generated, the alkylation of benzene and methanol, benzene and ethanol can only be carried out under high temperature and gas phase reaction conditions, so it faces the following common problems: (1) How to reduce the mutual isomerism between xylene and ethylbenzene chemical side reaction. That is to say, in the alkylation of benzene and methanol, the further isomerization reaction of the target product xylene to the by-product ethylbenzene should be minimized. ...

AI Technical Summary

Problems solved by technology

Because the small amount of xylene impurity that this side reaction generates can affect the purity of styrene downstream product, limit its scope of application; (2) how to slow down the deactivation rate of carbon deposition of catalyst under the condition of low benzene-alcohol ratio, so that catalyst can be used in Long-term operation under relatively mild conditions

[0003] The preparation method of benzene alkylation catalyst disclosed in existing patents does not solve the side reaction problem of isomerization of ethylbenzene and xylene well

In addition, the benzene alkylation catalysts disclosed in existing patents can only operate at a high benzene-to-alcohol ratio to have good activity stability

However, the use of a high benzene-alcohol ratio will lead to an increase in the amount of benzene circulation, which will greatly increase the energy consumption of industrial plants, which is not conducive to industrial applications.