乙醇在ZSM基催化剂上的分解与芳构化

Decomposition and aromatization of ethanol on ZSM-based catalysts.

作者信息

Barthos R, Széchenyi A, Solymosi F

机构信息

Institute of Solid State and Radiochemistry, University of Szeged and Reaction Kinetics Research Group of the Hungarian Academy of Sciences, PO Box 168, H-6701 Szeged, Hungary.

出版信息

J Phys Chem B. 2006 Nov 2;110(43):21816-25. doi: 10.1021/jp063522v.

DOI:10.1021/jp063522v

PMID:17064145

Abstract

The adsorption, desorption, and reactions of ethanol have been investigated on pure and promoted ZSM-5 catalysts. FTIR spectroscopy indicated the formation of a strongly bonded ethoxy species on ZSM-5(80) at 300 K. TPD experiments following the adsorption of ethanol on both ZSM-5 and Mo2C/ZSM-5 have shown desorption profiles corresponding to unreacted ethanol and decomposition products (H2O, H2, CH3CHO, C4H10O, and C2H4). The main reaction pathway of ethanol on pure ZSM-5 is the dehydration reaction yielding ethylene, small amounts of hydrocarbons, and aromatics. Deposition of different additives, such as Mo2C, ZnO, and Ga2O3 on zeolite, greatly promoted the formation of benzene and toluene at 773-973 K, very likely by catalyzing the aromatization of ethylene formed in the dehydration process of ethanol. Separate studies of the reaction of ethylene revealed that the previous additives markedly enhanced the selectivity and the yield of aromatics on ZSM-5.

摘要

已对乙醇在纯ZSM-5催化剂和促进型ZSM-5催化剂上的吸附、脱附和反应进行了研究。傅里叶变换红外光谱表明，在300K时，ZSM-5(80)上形成了强键合的乙氧基物种。乙醇吸附在ZSM-5和Mo2C/ZSM-5上后的程序升温脱附实验显示出对应于未反应乙醇和分解产物（H2O、H2、CH3CHO、C4H10O和C2H4）的脱附曲线。乙醇在纯ZSM-5上的主要反应途径是脱水反应生成乙烯、少量烃类和芳烃。在沸石上沉积不同的添加剂，如Mo2C、ZnO和Ga2O3，在773-973K时极大地促进了苯和甲苯的形成，很可能是通过催化乙醇脱水过程中形成的乙烯的芳构化反应。对乙烯反应的单独研究表明，先前的添加剂显著提高了ZSM-5上芳烃的选择性和产率。