摘要
制备了一系列Zn,P或Zn-P双组分改性ZSM-5沸石催化剂,并对其酸性和丙烯转化活性、选择性进行了表征。结果表明,于指定反应条件下,ZnZSM-5(Im,5％)样品的丙烯转化率为98.3％,苯选择性80.7％;Zn/PZSM-5(Im)样品的丙烯转化率为97.4％,二聚选择性95.6％。ZnZSM-5(Im,5％),ZnO/HZSM-5(pm,650)和Zn/PZSM-5(Im)三样品吸附吡啶后均呈现1616cm^(-1)峰,它表征一类缺电子中心,可能属于烯丙基活性中心,有利于丙烯二聚,在合适的微环境条件下,有利于二聚产物的环化、脱氢芳构化。
The activity and selectivity for the conversion of propene of a series of ZSM-5 zeolites modified with Zn, P, and Zn-P were determined. The acidity of the catalysts was investigated by IR of pyridine adsorption. At given reaction conditions, on the impregnated catalyst Zn-ZSM-5 (Im, 5%), a 98.3% conversion of propene and 80.7% selectivity for benzene are obtained. On the catalyst Zn/PZSM-5(Im), the conversion of propene is 97.4% and the selectivity for dimerization is 95.6%. For the catalysts such as Zn-ZSM-5(Im, 5%), ZnO/HZSM-5(Pm, 650℃) and Zn/PZSM-5 (Im), the formation of strong pyridine adsorption IR band at 1616cm-1 which is characterized as an electron deficient site is observed. The electron deficient site may be active in the formation of allyl from propene and is in favour of dimerizatioin, or cyclization and dehydroaromatization of the dimerization product.
