合成乙苯ZSM-5催化剂的FT-IR研究  

Study on ZSM-5 Catalysts for the Synthesis of Ethylbenzene by FT-IR

作　　者：曹玉华[1] 陆丽元[1] 程文才[1] 

机构地区：[1]上海石油化工研究院,上海201208

出　　处：《分子催化》1993年第3期233-238,共6页Journal of Molecular Catalysis(China)

摘　　要：ZSM-5沸石由于具有独特结构,作为新型的择形催化剂广泛应用于石油化工催化反应中.人们普遍认为这些催化反应是由于沸石的酸中心引起的,尤其是B酸中心,因此对此做了较多的研究.我们选用不同反应时间,苯与乙烯气相烷基化合成乙苯ZSM-5催化剂,用吡啶吸附方法研究了ZSM-5催化剂的酸性,结合催化剂活性考察数据,得到了一些有意义的信息.The surface acid character of ZSM-5 catalysts for the synthesis of ethylbenzene in a vapor phase process with various reaction times has been studied by FT-IR. The spectra show that 3612 cm-1OH groups reappear when pyridine was adsorbed on a fresh and a catalyst reacted for 100 h and then desorbed at temperatures≥400℃. It means that there are two kinds of Bronsted acid sites (strong and weak) in both catalysts. The strong Bronsted acid site is directly related to the 3612 cm-1OH groups. But there is mainly the weak Bronsted acid sites in the catalyst reacted for 62 days. Organic compounds and coke were detected by TGA in the reacted catalysts. It indicates that the surface and cages of the catalysts are partly covered or blocked by them which were formed gradually during the reaction. The coke is in direct proportion to the reaction time of the catalysts. It is proposed that the coke was chiefly deposited on sites characterized by 3612 cm-1OH groups (the strong Bronsted acid site). The deposition of coke caused the decrease of the Bronsted acid site. Meanwhile, the relationship between the acid site character and the catalytic activity is also suggested.

关 键 词：乙苯 分子筛 催化剂 沸石 ZSM-5 

分 类 号：O625.11[理学—有机化学]