文献类型：期刊文献

中文题名：改进千凝胶法制备多级孔ZSM-5促进苯甲基化多产二甲苯(英文)

英文题名：Promoting Xylene Production in Benzene Methylation using Hierarchically Porous ZSM-5 Derived from a Modified Dry-gel Route

作者：邓威[1];何暄[1];张超[1];高云逸[1];朱学栋[1];朱卡克[1];霍启升[2];周志杰[3]

机构：[1] College of Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, China; [2] State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012, China; [3] Key Laboratory of Coal Gasification, Ministry of Education, East China University of Science and Technology, Shanghai, 200237, China

年份：2014

卷号：22

期号：8

起止页码：921

中文期刊名：Chinese Journal of Chemical Engineering

外文期刊名：中国化学工程学报（英文版）

收录：CSTPCD;;EI(收录号：20143600005931);Scopus;CSCD:【CSCD2013_2014】；

基金：Supported by the National Natural Science Foundation of China(21006024);the CNPC Innovation Foundation(2011D-5006-0507);the Shanghai Pujiang Program(11PJ1402600);the New Century Excellent Talents in University(NCET-11-0644);the Fundamental Research Funds for the Central Universities(WB1213004-1)

语种：中文

中文关键词：ZSM-5分子筛;对二甲苯;甲基化;多级;生产;干凝胶;沸石催化剂;ZSM-5催化剂

外文关键词：Hierarchical zeolite;Benzene;Methanol;Methylation;ZSM-5;Process intensification

摘要：Methylation of benzene is an alternative low-cost route to produce xylenes,but selectivity to xylene remains low over conventional zeolitic catalysts.In this work,a combined dry-gel-conversion and steam-assistedcrystallization method is used to synthesize hierarchically porous zeolite ZSM-5 with varied Si/AI malar ratios.X-ray diffraction(XRD),N_2 physisorption,NH_3-temperature programmed desorption(TPD),scanning electronic microscopic(SEM) measurement and Fourier transform infrared(FT-IR) are employed to characterize the structure and acidity of both hierarchically porous zeolites and their conventional counterparts.The method is found to be applicable to ZSM-5 with molar ratios of Si/AI from 20 to 180.The ZSM-5 zeolites are used as catalysts for benzene methylation at 460 °C to investigate the effect of additional porosity and Si/AI ratios.At low Si/AI ratios,the benzene conversions over conventional and hierarchical ZSM-5 are close,and selectivity to toluene is high over hierarchical ZSM-5.It is found that hierarchical porosity markedly enhances the utility of zeolite and the selectivity towards xylenes via improved mass transport at higher Si/AI ratios.Under an optimized hierarchical ZSM-5 catalyst,xylene selectivity reaches 34.9%at a Si/AI ratio of 180.
Methylation of benzene is an alternative low-cost route to produce xylenes, but selectivity to xylene remains low over conventional zeolitic catalysts. In this work, a combined dry-gel-conversion and steam-assisted- crystallization method is used to synthesize hierarchically porous zeolite ZSM-5 with varied Si/AI malar ratios. X-ray diffraction （XRD）, N2 physisorption, NH3-temperature programmed desorption （TPD）, scanning electronic microscopic （SEM） measurement and Fourier transform infrared （FT-IR） are employed to characterize the struc- ture and acidity of both hierarchically porous zeolites and their conventional counterparts. The method is found to be applicable to ZSM-5 with molar ratios of Si/A1 from 20 to 180. The ZSM-5 zeolites are used as catalysts for benzene methylation at 460 ℃ to investigate the effect of additional porosity and Si/A1 ratios. At low Si/AI ratios, the benzene conversions over conventional and hierarchical ZSM-5 are close, and selectivity to toluene is high over hierarchical ZSM-5. It is found that hierarchical porosity markedly enhances the utility of zeolite and the se- lectivity towards xylenes via improved mass transport at higher Si/Al ratios. Under an optimized hierarchical ZSM-5 catalvst, xvlene selectivity reaches 34.9% at a Si/AI ratio of 180.