Development of catalyst for the synthesis of styrene from ethane and benzene

乙苯合成苯乙烯催化剂的研制

基本信息

批准号：
11650811
负责人：
SUZUKI Toshimitsu
金额：
$ 2.37万
依托单位：
Kansai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

A large quantity of styrene monomer was produced in the world from ethylene and benzene to give ethylbenzene followed by dehydrogenation. 3 step processes were required in the current technology. This project was planned to develop a simple and energy saving chemical process. For this, ethane was used for the alkylation of benzene using various acid catalysts such as zeolite. However, yield of ethylbenzene was very small. Considering that formation of ethyl cation from ethane is difficult, loading of several metal species which are capable of dehydrogenation of alkane was examined.Alkylation of benzene with ethane was carried out using various zeolite catalyst at temperature ranges of 400 to 550℃. Loading of platinum onto zeolite enhanced yield of ethylbenzene greatly. Among zeolite tested, H-ZSM5, H-AlMCM41, and H-MCM22 showed catalytic activities. However, mordenite did not give ethylbenzene. Moderate acid strength distribution is the key factor of zeolite catalyst. Optimum catalyst and conditions for this reaction is as follows :Platinum-loaded H-ZSM5 catalyst containing 6.8 wt % Pt, at the reaction temperature of 500℃, afforded ethylbenzene and styrene formation rates of 14.2 and 0.8 mmol h^<-1>・g^<-1> of catalyst, respectively (benzene-based yields 7.3 and 0.4 %). In the alkylation of benzene with ethane over platinum-loaded H-ZSM5, ethene would be initially formed from ethane over the metallic platinum. Then the alkylation would proceed over the acid sites of H-ZSM5.Dehydrogenation of ethylbenzene was investigated, and found that magnesium oxide-loaded vanadium oxide exhibited very high activity in the presence of carbon dioxide. Carbon dioxide promoted redox cycle of vanadium oxide during dehydrogenation reaction. Where lattice oxygen of vanadium oxide was gradually lost during dehydrogenation, then carbon dioxide reoxidized low valent vanadium oxide to higher valency state.

目前，世界上大量的苯乙烯单体由乙烯和苯生产乙苯，然后需要经过三步脱氢工艺来生产乙烷。用于使用各种酸催化剂（例如沸石）进行苯的烷基化，但是，考虑到乙基阳离子的形成，乙苯的产率非常小。乙烷的合成比较困难，因此对几种能够实现烷烃脱氢的金属物种的负载进行了研究。在400～550℃的温度范围内，使用各种沸石催化剂进行苯与乙烷的烷基化反应，大大提高了乙苯的产率。在测试的沸石中，H-ZSM5、H-AlMCM41 和 H-MCM22 显示出催化作用然而，丝光沸石不产生乙苯。适中的酸强度分布是沸石催化剂的关键因素，该反应的最佳条件如下：负载铂的H-ZSM5催化剂，在反应温度下。 500℃时，乙苯和苯乙烯的生成率为14.2和0.8 mmol h^<-1>·g^<-1> 催化剂（苯基产率分别为 7.3 % 和 0.4 %）。在负载铂的 H-ZSM5 上苯与乙烷的烷基化反应中，乙烷首先会形成乙烯。然后在H-ZSM5的酸性位上进行烷基化。研究了乙苯的脱氢反应，发现镁。负载氧化物的氧化钒在二氧化碳存在下表现出非常高的活性，二氧化碳在脱氢反应过程中促进氧化钒的氧化还原循环，其中氧化钒的晶格氧在脱氢过程中逐渐失去，然后二氧化碳将低价氧化钒重新氧化为高价氧化钒。价态。