C_9芳烃在不同结构分子筛催化剂上的反应

在C9芳烃轻质化的研究中,分别以1,2,4-三甲苯、邻甲乙苯及异丙苯为原料,对它们在不同结构分子筛(包括纳米HZSM-5,Hβ,HMOR沸石)催化剂上的反应进行了研究。实验结果表明,Hβ催化剂的初始活性最高并表现出较好的歧化能力,纳米HZSM-5催化剂则表现出较好的的脱烷基能力,HMOR催化剂的性能介于前两者之间。在C9芳烃的反应中,带有伯烷基、仲烷基和叔烷基的C9芳烃反应活性依次增加。随反应温度的升高,带有伯烷基和仲烷基的C9芳烃依次进行异构化、歧化和脱烷基反应;而带有叔烷基的C9芳烃则以脱烷基反应为主。各催化剂的酸性强弱顺序为:HMOR>Hβ>纳米HZSM-5,其活性高低顺序为:Hβ>纳米HZSM-5>HMOR,这说明分子筛催化剂的结构对C9芳烃反应的影响大于其酸性的影响。

Reactions of C9 Aromatics over Zeolite Catalysts with Different Structures

The reactions of C9 aromatics(1,2,4-trimethylbenzene,o-ethyltoluene and isopropylbenzene) over nanosized HZSM-5,Hβ and HMOR zeolites were studied.The results showed that the performances of the catalysts were in the sequence of Hβ>nanosized HZSM-5>HMOR.Hβ showed the high initial activity and disproportionation activity.The dealkylation of nanosized HZSM-5 was good.The catalytic activity of HMOR zeolite was between that of Hβ and nanosized HZSM-5.Hβ and nanosized HZSM-5 indicated the high transalkylation and dealkylation activities.With the reaction temperature rising,the C9 aromatics with primary and secondary alkyls carry out the isomerization,disproportionation and dealkylation in order.The C9 aromatics with tertiary alkyl mainly conduct the dealkylation.The acidities of the catalysts are HMOR>Hβ>nanosized HZSM-5,while their activities are Hβ>nanosized HZSM-5>HMOR,which means that the structures of the catalysts affected the reactions of C9aromatics more than their acidities.