ISOMERIZATION AND DISPROPORTIONATION OF META-XYLENE SELECTIVITIES INDUCED BY THE VOID STRUCTURE OF THE ZEOLITE FRAMEWORK

被引:162
作者
MARTENS, JA [1 ]
PEREZPARIENTE, J [1 ]
SASTRE, E [1 ]
CORMA, A [1 ]
JACOBS, PA [1 ]
机构
[1] CSIC, INST CATALISIS & PETROLEOQUIM, E-28006 MADRID, SPAIN
来源
APPLIED CATALYSIS | 1988年 / 45卷 / 01期
关键词
Catalysts--Selectivity - Chemical Reactions--Isomerization - Crystallography--Microstructure - Xylene--Catalysis;
D O I
10.1016/S0166-9834(00)82395-7
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
The conversion of m-xylene was performed on acid zeolites with ten-or twelve membered rings, such as ZSM-5, ZSM-12, ZSM-48, OFF, MOR, FAU, Ω, β and L. All of these zeolites have distinctly different crystallographic structures with different shapes and dimensions of the intracrystalline cavities. This diversity of pore structures allowed to determine to what extent the pore shape and dimensions influence the selectivity of the reaction of m-xylene. The p/o selectivity in the isomerization of m-xylene is always high for the ten-membered ring zeolites with crystals bigger than 1 μm. The moderate selectivity for p-xylene formation in some zeolites with twelve-membered rings is due to transition-state shape selectivity. The selectivity for disproportionation versus isomerization is very low for ten-membered ring zeolites and allows them to be distinguished easily from the twelve-membered ring zeolites, which show much more disproportionation.
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页码:85 / 101
页数:17
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