关键词: 联苯烷基化, MCM-22分子筛, 金属氧化物改性, 络合浸渍

Abstract: 4,4'-dicyclohexyl biphenyl (4,4'-DCBP) and 4-cyclohexylbiphenyl (4-CBP) were synthesized by MCM-22 zeolite catalyzed reaction between biphenyl and cyclohexene. The MCM-22 zeolite modified by Mg or Co was prepared by ordinary impregnation method, the difference between complexed impregnation with citric acid and common impregnation was compared, and the samples were characterized by XRD, BET, NH3-TPD and SEM, and the catalytic performance was evaluated under the conditions of n(biphenyl):n(cyclohexene)=1:1.5, an initial pressureof 0.5 MPa,a reaction temperature of 230°C, and areaction time of200 min. The results showed that the two impregnation methods reduced the crystallinity, specific surface area, acid content and acid strength of zeolite. Complexation impregnation can effectively prevent metals from entering the molecular sieve pores, thereby reducing the blockage of the pores by Mg under higher loads, but complexing impregnationof Co at 4% and more than 4% loading causes excessive coverage of metal oxides on the surface of molecular sieves. The 4Co MCM-22 zeolite prepared by 4% ofCo by common impregnation showed the best catalytic performance, and obtained a biphenyl conversion rate of 56.5%, a target product selectivity of 67.2% and a target product yield of 38.0%.

Key words: biphenyl alkylation, MCM-22 zeolite, metal oxide modification, complexation impregnation