High-selectivity method for synthesizing styrene through methanol and toluene side chain alkylation

Abstract

The invention relates to a high-selectivity method for synthesizing styrene through methanol and toluene side chain alkylation, namely a high-selectivity method for preparing styrene through toluene and methanol alkylation by use of an alkaline molecular sieve based catalyst under the condition of taking carbon dioxide as a reaction medium. In the method for synthesizing styrene through toluene and methanol alkylation by use of a molecular sieve based catalyst containing metal aid modification, in the presence of a carbon dioxide medium, the mixture of toluene and methanol at a molar ratio of 2.0-8.0 is used as a raw material, the reaction temperature is 350-540 DEG C, the toluene reaction airspeed is kept at 0.1-4.0/h, the pressure of the reaction medium is kept at 0.1-6.0MPa, and the molar ratio of carbon dioxide to hydrocarbon is kept at 0.5-10.0. According to the invention, by taking a large amount of excessive greenhouse gas carbon dioxide as a reaction medium, the styrene is prepared with a high yield, and the problems of many side reactions and poor selectivity in the existing styrene synthesis technology through toluene and methanol alkylation are solved; and moreover, the reaction stability can be improved so that the catalyst stability and styrene selectivity in the styrene synthesis through toluene and methanol alkylation meet the requirements of industrial application.

Description

technical field [0001] The invention relates to a method for synthesizing styrene with side chain alkylation of methanol and toluene with high selectivity, that is, under the reaction medium of carbon dioxide, the method of continuously and stably reacting the alkylation of toluene and methanol with high selectivity to synthesize styrene is realized through molecular sieve catalysts new method. Background technique [0002] Styrene is the most important raw material for the synthesis of polystyrene, styrene-butadiene rubber and ion exchange resin, and it is the fourth largest ethylene derivative product after PE, PVC and EO. The demand for styrene has been growing continuously, and the production capacity of styrene in my country has always been in short supply, and the annual import volume is about 3 million tons. At present, its main industrial production method, the synthesis of styrene by dehydrogenation of ethylbenzene, has the problems of many side reactions, large am...

AI Technical Summary

Problems solved by technology

It uses carbon dioxide as the reaction medium and molecular sieve modified with metal additives as the catalyst. While producing styrene in high yield, it not only solves the problem of low selectivity of styrene produced by the alkylation of toluene and methanol, but also effectively inhibits the production of styrene. The process of deactivation caused by carbon formation on the catalyst also solves the problem of poor stability in the reaction of alkylation of toluene and methanol to prepare styrene

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