Method for improving stability of ZSM-5 zeolite catalyst for preparation of phenylacetaldehyde by styrene oxide rearrangement

Abstract

Belonging to the catalytic field of fine chemicals, the invention relates to a method for improving the stability of a ZSM-5 zeolite catalyst for preparation of phenylacetaldehyde by styrene oxide rearrangement. The method includes: firstly subjecting a ZSM-5 zeolite catalyst to alkaline solution treatment, then loading a certain amount of phosphorus or boron through impregnation, and adjusting the pore structure and acidity of zeolite respectively. Specifically, alkali treatment can introduce a mesoporous structure into the zeolite structure, the loaded phosphorus or boron can reduce the acidstrength of zeolite strong acid site, the diffusion rate of molecules is increased in the catalytic reaction process, the probability of side reaction and the formation of carbon deposit are reduced,the catalyst stability is improved by 8-10 times, and no obvious deactivation occurs to the catalyst after 100h of continuous operation.

Description

technical field [0001] The invention belongs to the technical field of fine chemical industry catalysis, and in particular relates to a method for improving the stability of a ZSM-5 zeolite catalyst used for rearrangement of styrene oxide to prepare phenylacetaldehyde. Background technique [0002] Phenylacetaldehyde is an organic intermediate with hosta fragrance, widely used in the preparation of essences, fragrances, drugs, insecticides, fungicides and herbicides. The preparation methods of phenylacetaldehyde mainly include oxidation and reduction. The oxidation method mainly uses phenylethanol, styrene or styrene glycol as raw materials to obtain phenylacetaldehyde through catalytic oxidation. The reduction method mainly uses phenylacetic acid, methyl phenylacetate or ethyl phenylacetate as raw materials to obtain phenylacetaldehyde through catalytic reduction. Due to the active nature of phenylacetaldehyde, it is easy to continue to oxidize to generate phenylacetic ac...

AI Technical Summary

Problems solved by technology

However, phenylacetaldehyde is prone to side reactions such as aldol condensation and polymerization, and some macromolecular polymers are deposited on the surface of the catalyst and form carbon deposits, resulting in rapid deactivation of the catalyst.

US5225602 discloses that styrene oxide can be rearranged to phenylacetaldehyde on a ZSM-5 zeolite catalyst. At 200°C and WHSV = 3.0 h-1, the conversion rate of styrene oxide can reach 100%, and the selectivity of phenylacetaldehyde It can reach more than 90%, but the catalyst will start to deactivate after 6 hours of continuous reaction

US4929765 discloses the reaction of styrene oxide or styrene glycol on ZSM-5 zeolite to obtain phenylacetaldehyde, under the condition of 70-200 ℃, WHSV = 2.5 h-1 and reduced pressure, the gas phase conditions in the tubular reactor By adjusting the flow rate of the carrier gas and controlling the residence time of the raw materials in the catalyst bed to less than 4 s, the probability of side reactions such as aldol condensation and polymerization of phenylacetaldehyde can be greatly reduced, and the carbon deposition on the surface of the catalyst can be reduced, but the stability of the catalyst performance is still not up to the requirements of industrial applications