A kind of hierarchical porous hβ molecular sieve catalyst for preparing diphenylamine by condensation of aniline and its preparation method and application

Abstract

The invention discloses a hierarchical pore Hbeta molecular sieve catalyst for preparing diphenylamine by condensing aniline. The hierarchical pore Hbeta molecular sieve catalyst is prepared by virtue of a direct synthetic method or a micropore molecular sieve modification indirect synthetic method. The invention also discloses a preparation method of the hierarchical pore Hbeta molecular sieve catalyst as well as an application in preparing diphenylamine by catalyzing the condensation of the aniline. Under the effect of a formed catalyst prepared by the hierarchical pore Hbeta molecular sieve catalyst, the aniline has a self-condensation reaction to prepare diphenylamine, the reaction temperature is 290 to 370 DEG C, the reaction pressure is 1.5MPa to 5MPa, and the airspeed is 0.1 to 0.7 / h. The molecular sieve catalyst has the advantages of good catalytic activity, good stability and high diphenylamine selectivity. Compared with the corresponding ordinary micropore Hbeta molecular sieve, the conversion rate of the aniline is at least increased by 23%, the selectivity of the diphenylamine is at least increased by 1%, and the service life of the catalyst can reach more than 7000 hours.

Description

technical field [0001] The invention belongs to the field of chemical industry, and relates to a multi-level porous Hβ molecular sieve catalyst for preparing diphenylamine by condensation of aniline and its preparation and application. Background technique [0002] Diphenylamine is an important fine organic chemical raw material with a wide range of uses, mainly used in rubber additives, explosive stabilizers, pharmaceuticals, dyes and other industries. The traditional production method of synthesizing diphenylamine from aniline is a batch-type liquid-phase catalytic synthesis method. Since aluminum trichloride is used as a catalyst, the equipment is severely corroded during production, the environment is polluted, the reaction selectivity is low, and the separation of the catalyst and the product is difficult. Production The process route is long, the unit consumption of raw materials is high, and the product cost is high. [0003] In order to overcome the shortcomings of ...

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Problems solved by technology

[0006] It can be seen from the above-mentioned patents that in the process of continuous preparation of diphenylamine in liquid phase from aniline, the catalyst with Hβ molecular sieve and alumina as the main components has good catalytic activity and high selectivity, but this type of catalyst loses its strength after being used for less than half a year. activity, must be regenerated or replaced with a new catalyst

Catalyst deactivation is mainly caused by carbon deposits. With the prolongation of operation time, the by-product compounds are pyrolyzed and condensed to form carbon deposits and viscous high-molecular nitrogen-containing polymers, which are deposited on the surface of the catalyst and block the micropores of the catalyst. , covering the acid active center of the catalyst, leading to a gradual decline in catalyst activity

[0007] The Hβ molecular sieves used in the above inventions all have a microporous structure, and the pore size of the molecular sieve is generally about 0.65nm. Since the pore size of the Hβ molecular sieve is similar to the molecular size of the reactants and products, the molecules diffuse slowly in the pores and easily cause carbon deposition. It is not conducive to improving the activity, service life and product selectivity of the catalyst

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