Preparation method of 2, 6-di-tert-butyl p-cresol

Abstract

The invention relates to a preparation method of 2, 6-di-tert-butyl p-cresol, and belongs to the technical field of organic chemical synthesis. According to the method, a modified mesoporous silica loaded Nb / Mo / Cu three-metal active center catalyst is used as a catalyst, m-cresol, p-cresol and isobutene are mixed to be used as raw materials, ultrasonic cavitation is carried out in the catalytic reaction process, and then 2, 6-di-tert-butyl p-cresol is prepared. Mixed cresol is used as a raw material, so that a cost is reduced, during preparation of 2, according to the method, m-cresol is separated while 2, 6-di-tert-butyl-p-cresol is separated, by research, it is discovered that the modified mesoporous silica loaded Nb / Mo / Cu three-metal active center catalyst has a synergistic catalytic effect of the three-metal active center, the conversion rate of the mixed cresol and the selectivity of the di-tert-butyl cresol are greatly improved, especially, the selectivity of the 2, 6-di-tert-butyl-p-cresol is improved, impurities such as 2-tert-butyl-p-cresol and 6-tert-butyl-m-cresol are reduced, meanwhile, under the action of ultrasonic cavitation, a liquid-gas reaction is promoted to forma microreactor in micropores in a solid catalyst, the catalytic activity is greatly improved, the gas-liquid two-phase mass transfer efficiency and heat transfer area are increased, and the conversion rate of raw materials is further increased.

Description

technical field [0001] The invention relates to a preparation method of 2,6-di-tert-butyl-p-cresol, belonging to the technical field of organic chemical synthesis. Background technique [0002] 2,6-Di-tert-butyl-p-cresol (BHT) is a common phenolic antioxidant widely used in food processing, feed additives, petroleum products, plastics and rubber, etc. It is a multi-purpose, non-coloring , The largest amount of phenolic antioxidants. [0003] At present, the production process of isobutylene and p-cresol under the action of a catalyst to produce the antioxidant BHT is mostly used at home and abroad. The catalyst has experienced the evolution of liquid concentrated sulfuric acid and solid sulfonic acid. Chinese patent CN 103694085B reports that p-cresol and isobutanol are used as raw materials, and concentrated sulfuric acid is added as a catalyst to synthesize the antioxidant BHT; this method not only produces a large amount of waste water, but the synthesis efficiency is lo...

AI Technical Summary

Problems solved by technology

Chinese patent CN 103694085B reports that p-cresol and isobutanol are used as raw materials, and concentrated sulfuric acid is added as a catalyst to synthesize antioxidant BHT; this method not only produces a large amount of waste water, but the synthesis efficiency is low, and the use of concentrated sulfuric acid catalyst seriously corrodes the equipment

Chinese patent CN102311318A has reported using p-cresol and isobutylene as raw materials, adding p-arylsulfonic acid as a catalyst to synthesize 2,6-di-tert-butyl p-cresol; Wastewater by-products, but arylsulfonic acid will also cause greater corrosion to the reactor. In addition, the cost of using p-cresol as a raw material is relatively high

[0004] And the existing solid catalyst, such as Chinese patent CN107737605A, has reported that any modified molecular sieve in ammonium phosphate, ammonium hydrogen phosphate, and ammonium dihydrogen phosphate is used as a carrier to support active component A and active component B, wherein the The molecular sieve is Hβ molecular sieve, hydrogen mordenite, HY molecular sieve, USY molecular sieve, REY molecular sieve or SAPO-5 molecular sieve, active component A is Co, Cu, Ni or Fe, active component B is phosphotungstic acid, silicotungstic acid , phosphomolybdic acid, silicomolybdic acid, and sodium tungstate, but there are still problems of low conversion rate of raw materials and low selectivity of products

[0005] At present, there is still the problem that mixed cresols (m-cresol and p-cresol) are not easy to separate. As reported in Chinese patent CN102898281A, mixing m-p-cresol and isobutylene in catalyst sulfuric acid or solid S-ZrO 2 The alkylation reaction is carried out under the catalysis of the catalyst, and after rectification, three products of 2,6-di-tert-butyl-p-cresol, m-cresol and 6-tert-butyl-m-cresol are co-produced, but the patent still There is a problem of corroding equipment when sulfuric acid is used, and S-ZrO is used 2 When the conversion rate of raw materials is low, the problem of low selectivity of 2,6-di-tert-butyl-p-cresol and 4,6-di-tert-butyl-m-cresol

[0006] At present, liquid catalysts are still highly corrosive, and solid catalysts still have the problems of low raw material conversion and low product selectivity.