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采用低分子季铵碱(或盐)、低分子醇或氢氧化铵为阳离子成功地合成了ZSM-5型沸石。这些沸石的主要物性数据与文献值基本一致,但它们在用于甲醇转化为烃的反应中性能差别较大。初步考察了沸石的硅铝比和晶粒大小对甲醇转化的影响,发现沸石的平均晶粒约大于7μ或硅铝比高于150左右时表现出对于二甲苯异构体有择形作用,产物中对位二甲苯量超过热力学平衡值。此外,还考察了操作参数与沸石催化性能的关系。
ZSM-5 zeolite has been successfully synthesized using low molecular quaternary ammonium (or salt), low molecular alcohol or ammonium hydroxide as cation. The major physical properties of these zeolites are in line with the literature values, but they differ widely in their performance for the conversion of methanol to hydrocarbons. The effects of silica to alumina ratio and grain size on the conversion of methanol were investigated. It was found that when the average grain size of zeolite is larger than 7μ or the ratio of Si / Al is higher than 150, the zeolite has the shape selective effect on xylene isomers. The amount of para-xylene exceeds the thermodynamic equilibrium value. In addition, the relationship between operating parameters and zeolite catalytic performance was also investigated.