A kind of method for synthesizing cyclohexylbenzene by liquid-phase alkylation of benzene and cyclohexene

Abstract

The invention discloses a method for synthesis of cyclohexylbenzene by liquid phase alkylation of benzene and cyclohexene. The method includes: a process I of subjecting benzene, cyclohexene and cyclohexane to contact reaction in the presence of a catalyst containing an FAU structure molecular sieve to obtain cyclohexylbenzene, a process II of subjecting benzene and polycyclohexylbenzene to contact reaction to further obtain cyclohexylbenzene, and a separation process. The products of the process I and the process II can be subjected to the separation process so as to at least obtain benzene, cyclohexane, cyclohexylbenzene and polycyclohexylbenzene. Specifically, the benzene obtained by the separation process is reused in the process I and / or process II through recycling, and the polycyclohexylbenzene involved in the process II comes from the separation process. In the method, the existence of cyclohexane can significantly inhibit inactivation of an FAU structure molecular sieve catalyst.

Description

technical field [0001] The invention relates to a method for synthesizing cyclohexylbenzene by liquid-phase alkylation of benzene and cyclohexene, in particular to a method for prolonging catalyst life by liquid-phase alkylation of benzene and cyclohexene to synthesize cyclohexylbenzene . Background technique [0002] Cyclohexylbenzene is an important chemical intermediate. Its high boiling point (240°C) and low freezing point (7°C) give it special physical and chemical properties. Cyclohexylbenzene can be oxidized to produce cyclohexylbenzene hydroperoxide, which can be decomposed to produce phenol and cyclohexanone. Phenol is a chemical raw material in great demand, and cyclohexanone is used to produce caprolactam and Intermediates of nylon. Cyclohexylbenzene can be used as an additive for the electrolyte of lithium-ion secondary batteries, can improve the cycle performance of lithium-ion batteries, has anti-overcharge performance, and can improve the safety of batteries...

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Problems solved by technology

[0004] U.S. Patent US4206082 reports a method for preparing cyclohexylbenzene by catalytically hydroalkylating benzene with a supported catalyst (M / X or Y-type molecular sieve, M is metal nickel and ruthenium). This method actually hydrogenates benzene The two-step reaction of synthesizing cyclohexene and the alkylation of benzene and cyclohexene to synthesize cyclohexylbenzene is combined into one, and the conversion rate of its benzene is lower than 15%. Although the selectivity of cyclohexylbenzene has been improved, it is still unsatisfactory (the selectivity of cyclohexylbenzene is lower than 80.6%); US20100179351, US20100197971 and US7910779 disclose a metal-loaded catalyst (wherein the metal is selected from palladium , ruthenium, nickel, zinc, cobalt and tin, and the carrier is any combination of MCM-22 molecular sieves), catalyzing the hydroalkylation reaction of benzene, the conversion rate of benzene has increased, but it is still lower than 60% , the selectivity of cyclohexylbenzene is lower than 88%

[0005] AppliedCatalysisA:General143(1996)271-281 reported that benzene and cyclohexene in SiO 2 grafted A1C1 3 The method of carrying out liquid-phase alkylation under the action of a catalyst has a conversion rate of cyclohexene of 97.9%, and a selectivity of cyclohexylbenzene of 97%, but the problems of this method are: the catalyst pollutes the environment, product recovery and purification Complex, poor reusability

[0006] CN1982263A and CN1982264A have reported respectively the method that benzene and alkylating reagent cyclohexanol or halogenated cyclohexane prepare cyclohexylbenzene by alkylation reaction, but the common defect that they exist is that the price of used alkylating reagent is expensive and the used The catalyst is more corrosive

[0007] CN101219922A discloses that benzene and cyclohexene prepare cyclohexylbenzene under the condition that benzene and cyclohexene are used as catalysts in imidazole ionic liquid and metal halide or triethylamine hydrochloride ionic liquid and metal halide. CN101811924A reports that benzene and cyclohexene react in pyridine Quasi-ionic liquids are a method for the preparation of cyclohexylbenzene catalyzed by catalysts, but the production process of ionic liquids is very complicated, resulting in their generally expensive prices, and ionic liquids are particularly sensitive to water, and are easily inactivated by partial hydrolysis after contact with water. It will fail and affect the efficiency of recycling. These are the big problems that restrict its development and are not conducive to industrial applications.

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