MWW型分子筛的高效清洁合成及其在苯与乙烯烷基化反应中催化性能

研究了MWW型分子筛合成过程中模板剂六亚甲基亚胺加入量对产物晶相、结晶度、形貌、孔结构和酸性等物化性能的影响。结果表明,通过加入晶种,利用晶种的导向作用,能有效提高MWW型分子筛的晶化速率,大幅降低配料中有毒模板剂六亚甲基亚胺用量,达到分子筛高效清洁生产的目的。在制得的MWW型分子筛中加入黏结剂制成催化剂,工业装置操作条件下评价其在苯与乙烯液相烷基化反应中的活性、选择性、产物分布及稳定性等,并进行了2 000 h寿命试验,结果表明,乙烯转化率接近100%,乙基化选择性大于99.7%,催化剂性能稳定,满足工业应用要求。

Preparation of MWW zeolites via a highly efficient clean method and their catalytic properties in benzene alkylation with ethylene

The influence of structure direct agent hexamethyleneimine (HMI) amount on product physicochemical properties such as crystal phase, crystallinity, morphology, pore structure and acidity during the synthesis of MWW zeolites were investigated. The results showed that introduction of crystal seed accelerated the crystallization rate of MWW zeolites, and then lowered the amount of toxic HMI. Consequently, the highly efficient clean preparation purpose of MWW zeolites was achieved. The catalysts were prepared by adding the binder to the as-prepared MWW zeolites. The catalytic performance of the catalysts in benzene liquid phase alkylation with ethylene,including activities, selectivity, product distribution and stability was investigated under the commercial operation condition. The 2 000 h life-time tests of the catalyst were carried out. The results showed that the catalyst possessed stable catalytic properties with ethylene conversion of nearly 100% and ethylation selectivity over 99.7%. The as-prepared catalyst met the requirements of industrial application.