阳离子改性HZSM-5沸石上低碳醇反应历程的TPSR-MS研究  

TPSR-MS STUDIES ON THE REACTION PATHS FOR LOWER ALCOHOLS CONVERSION OVER CATION-MODIFIED HZSM-5 ZEOLITES

作　　者：王锦业[1] 王定珠[1] 卢学栋[1] 

机构地区：[1]中国科学院山西煤炭化学研究所

出　　处：《Chinese Journal of Catalysis》1993年第5期392-397,共6页催化学报（英文）

基　　金：国家自然科学基金;山西省自然科学基金资助项目

摘　　要：用TPSR-MS技术研究了Cu,Zn和Ga改性H-ZSM-5沸石的活性中心性质及C_1～C_4醇的反应历程。结果表明,Zn-和Ga-ZSM-5有两种芳构化活性中心,即B酸和Zn,Ga活性物种;甲醇在Cu-ZSM-5上只生成二甲醚、CO和CO_2,而在Zn-ZSM-5上较其它醇易于吸附和转化为芳烃。上述结果为不同的催化行为提供了解释。低碳醇在改性ZSM-5上芳构化反应历程为:(1)醇经由醚脱水生成烯烃,C_2～C_4醇还可单分子脱水生成烯烃;(2)烯烃中间物齐聚,齐聚物通过氢转移和脱氢途径环化、芳构化;(3)Zn-和Cu-ZSM-5还能促进甲醇分解。以上各反应途径的贡献因改性组分和反应物不同而异。The active sites and the conversion pathway of C1-C4 alcohols over Cu-, Zn- and Ga-modified HZSM-5 zeolites have been studied by TPSR-MS technique.There are two kinds of aromatization active sites on Zn-and Ga-ZSM-5 zeolites, i.e.the Bronsted acid sites and the dehydrogen-ating active sites related to Zn and Ga species.Cu-ZSM-5 is less active for methanol conversion to hydrocarbons,but active for methanol decomposition.It is also found that over Zn-ZSM-5, methanol is accessible to and adsorbed on the Zn species, thus forming more aromatics than other alcohols.The reaction paths for lower alcohols conversion over the modified zeolites are as follows; (1) lower alkenes formation through dimolecular and monomolecular (except methanol) dehydration; (2) lower alkenes inter-conversion, oligomerization, oligomer cyclization and aromatization via H-transfer and dehydrogenation; ( 3 ) methanol decomposition catalyzed by Zn and Cu species.The contribution of the different reaction pathways varies with the modifying cations and reactants used.

关 键 词：沸石 阳离子改性 低碳醇 转化历程 

分 类 号：O623.411[理学—有机化学]