不同硅铝比SAPO-44分子筛合成及甲醇制烯烃催化性能研究

摘要

SAPO-44 molecular sieves with different Si contents were hydrothermally synthesized by using cyclohexylamine as the template. The samples were characterized by XRD, SEM, NH3-TPD and tested as the methanol-to-olefins (MTO) catalysts. The results showed that, as the Si/Al ratio increased, the relative degree of crystallinity and the surface acidity increased, and some non-cubic crystals were found out. At the same time, the initial selectivity of olefins decreased and the propylene/ethylene mass ratio increased with the Si content of SAPO-44 sample.%以环己胺为模板剂，合成了不同硅铝比的SAPO-44分子筛，分别采用XRD、SEM、NH3-TPD等表征手段对所合成的样品进行了表征，并在固定床上考察了样品的甲醇制烯烃催化性能。结果表明，随着硅铝比的增加，样品的相对结晶度有所增加，表面酸性有增强的趋势，分子筛晶体出现一些非立方晶体物种；同时，初始烯烃选择性随着硅铝比的增加而降低，反应产物中的丙烯/乙烯质量比则呈现升高的趋势。