Activity and basicity of BaO modified zeolite and zeolite-type catalysts

被引:38
作者
Arishtirova, K [1 ]
Kovacheva, P [1 ]
Predoeva, A [1 ]
机构
[1] Bulgarian Acad Sci, Inst Catalysis, BU-1113 Sofia, Bulgaria
关键词
basic zeolite and zeolite-type catalysts; BaO; oxidative methylation; toluene; methane; TPD of CO2; XPS;
D O I
10.1016/S0926-860X(02)00544-6
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
BaO modified zeolite and zeolite-type catalysts provide new and valuable data about the alternative reaction for ethylbenzene and styrene formation-the oxidative methylation of toluene with methane. Over BaO modified X, Y, mordenite, ZSM-5, silicalite and AIPO(4)-5 catalysts, the toluene conversion, selectivity and yield of C-8 hydrocarbons (ethylbenzene and styrene) are affected to a different degree by the reaction temperature. Both activity and basicity (measured by TPD Of CO2) are resultant from the combined effect of chemical composition and geometry of zeolite and zeolite-type structures, as well as from the accessibility of BaO modifier to the reagents. The Si/Al atomic ratio determines the catalytic and basic properties within a series of the same structural type. The zeolite and zeolite-type structural geometry determines the accessibility of the introduced BaO. Higher accessibility of BaO used for modification favors the activity. Basicity measurements by X-ray photoelectron spectroscopy (XPS) are mainly sensitive towards the chemical composition of the zeolite and zeolite-type framework. (C) 2002 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:191 / 196
页数:6
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