MCM-22 分子筛的合成及液相烷基化合成乙苯性能研究

Synthesis of MCM-22 and Its Catalytic Performance in the Liquid PhaseAlkylation for Ethylbenzene

对各种条件下合成的MCM-22沸石进行了表征研究。研究表明晶化时间对MCM-22沸石的层间结构有着显著的影响,晶化40 h后,其结构趋向稳定。MCM-22沸石沸石具有较高的B酸含量,强酸中心主要为B酸,MCM-22晶体呈片状结构,其结构中存在丰富的大孔。以MCM-22沸石为催化剂考察了其催化乙烯和苯的液相烷基化的反应性能。结果表明,MCM-22沸石催化剂具有优良的选择性,在低苯烯比(B/E)的反应条件下,其反应稳定性优良。在乙烯质量空速达到0.7 h^(-1),苯烯摩尔比(B/E)可以降低到2.0,乙苯选择性达到84%,二甲苯含量小于50 mg/kg。

The zeolites MCM-22 synthesized under various congditions were characterized. The results indicated that the layer structure of MCM-22 changed with crystallization time, and however became stable after 40 h crystallization. MCM-22 synthesized had much Brφnsted acid sites, moreover, which were mainly strong acid sites. The crystal form of synthesized MCM-22 was sheetlike and large amount of macropores were present in the zeolite. As catalyst for alkylation of benzene with ethene, MCM-22 showed much selective to ethylbenzene and better reaction stability than that of Beta zeolite under low benzene to ethene molar ratio （B/E） condition. The selectivity to ethylbenzene was about 84% when ethene space velocity （WHSV） was about 0.7 h^-1 and B/E was about 2.0.