Composite type catalyst, preparation method of composite type catalyst and application in methylbenzene

Abstract

The invention discloses a composite type catalyst, a preparation method of the composite type catalyst and application in methylbenzene. The composite type catalyst is prepared from alkaline molecularsieve based catalysts, alkali metal refractory salt and a boracic type catalyst; and the alkali metal refractory salt is loaded on the alkaline molecular sieve based catalysts. The composite type catalyst is used for methylbenzene and the process of preparing styrene by using methyl alcohol, and the methylbenzene percent conversion, methyl alcohol use ratio and styrene yield can be effectively improved. On the other hand, the invention further provides the preparation method and application of the composite type catalyst.

Description

technical field [0001] The invention relates to a composite catalyst, its preparation method and its application in side chain alkylation of toluene and methanol, belonging to the field of catalysis. Background technique [0002] As an important monomer of polymers, styrene is mainly used in the production of chemical products such as polymers. The traditional styrene production technology is ethylbenzene dehydrogenation method, which has a series of problems such as long process route, large equipment investment, many side reactions, high energy consumption and excessive dependence on petroleum resources. Therefore, the new styrene production process has received widespread attention. [0003] Compared with the traditional styrene production technology, the side-chain alkylation of toluene and methanol to styrene has a wide range of raw materials, omits the dehydrogenation step, reduces energy consumption and cost, and chooses methanol as the alkylation agent to reduce the...

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Problems solved by technology

[0005] US 4483936 reported that the X-type molecular sieve modified by alkali metal Cs and Rb has higher activity, and the X-type molecular sieve modified by direct impregnation with CsOH has the best activity, and the X-type molecular sieve modified by Cs single component has a styrene selectivity of 30%. Above, the total yield reaches more than 10%. This type of alkali metal significantly enhances the surface alkalinity of the molecular sieve and improves the catalytic performance, but it does not solve the problem of catalyst stability.

US 4115424 and US 5015796 report that adding a small amount of boron or phosphorus in the X-type molecular sieve of alkali metal ion exchange can improve the selectivity of styrene and improve the stability of the reaction at the same time, although the X-type molecular sieve is loaded with boron, its reaction temperature is greatly reduced , but there is still the problem of low styrene yield

CN 101623650A adopts K or Cs nitrate, acetate, carbonate and chloride to perform ion exchange on X or Y type molecular sieve, and supports boron, phosphorus and at least one of alkali metal and alkaline earth metal to make a catalyst to Improve the yield of styrene in the side chain alkylation of toluene and methanol, but the problem of catalyst life is still an urgent problem to be solved

CN10623649A has greatly improved the problem of catalyst stability caused by the easy destruction of molecular sieve catalyst structure through alkali metal-exchanged X-type or Y-type molecular sieves under the condition of 350-900 ° C. However, the selectivity of styrene lower

CN 106622342A uses rare earth elements to modify X or Y-type molecular sieves. This method better solves the problems of low methanol utilization rate, low toluene conversion rate and poor catalyst stability, but there is still the problem of low selectivity to styrene. question

[0006] In summary, the process route still has problems such as low toluene conversion, low methanol utilization, low styrene selectivity in the product, high ethylbenzene content, and poor catalyst stability, which hinder the side chain alkylation of toluene and methanol. Further industrial applications of the process

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