摘要
运用密度泛函理论研究了B和Ga改性的ZSM-5分子筛催化基于芳烃侧链机理的MTO(methanol to olefin)反应,并与未改性的ZSM-5催化反应的结果进行了比较。结果表明:在三个分子筛(ZSM-5,B-ZSM-5和Ga-ZSM-5)中,对于整个基于芳烃的侧链机理,决速步骤是对二甲苯的甲基化。从中间体M5开始,生成乙烯的决速步骤都是乙烯的消除;而对于生成丙烯,其决速步骤都是3,3-二甲基-6-亚乙基-1,4-环己二烯的甲基化。与未改性的ZSM-5相比,B改性的ZSM-5分子筛尽管反应活性降低了,但使得甲醇制乙烯的选择性高于制丙烯的选择性,而Ga改性的ZSM-5分子筛对甲醇制乙烯和丙烯的选择性和活性影响都不大。
The effect of B and Ga addition on ZSM-5 zeolite catalysting the MTO reaction based on aromatics side-chain mechanism was studied by denstiy functional theory method.The calculations show that in these three kinds of zeolite(ZSM-5,B-ZSM-5 and Ga-ZSM-5),the rate-limiting step is the methylation of p-xylene for the entire aromatics side-chain mechanism.Starting from the intermediate M5,the rate-limiting step of producing ethene is the elimination of ethene.For the formation of propene,the rate-limiting step is methylation of 3,3-dimethyl-6-ethylidene-1,4-cyclohexane.Compared with unmodified ZSM-5,the reactivity is reduced over B-ZSM-5.However,the selectivity of methanol to ethene is higher than that of methanol to propene over B-ZSM-5.There is little effect on the selectivity and activity of methanol to ethene and propene over Ga-ZSM-5.
作者
连霞霞
刘红艳
张海荣
刘平
章日光
凌丽霞
王宝俊
LIAN Xiaxia;LIU Hongyan;ZHANG Hairong;LIU Ping;ZHANG Riguang;LING Lixia;WANG Baojun(Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province,Taiyuan University of Technology,030024 Taiyuan,China;College of Chemistry and Environmental Engineering,Shanxi Datong University,037009 Datong,China;State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Science,030001 Taiyuan,China;College of Chemistry and Chemical Engineering,Taiyuan University of Technology,030024 Taiyuan,China)
出处
《煤炭转化》
CAS
CSCD
北大核心
2019年第5期67-74,共8页
Coal Conversion
基金
国家自然科学基金资助项目(21506120)
山西省回国留学人员科研资助项目(2016-104)
