不同模板剂制成的β沸石对苯与丙烯烷基化反应的影响

采用XRD和TPD技术对两种不同模板剂合成的β沸石(F-β沸石，W-β沸石)进行了孔结构的表征。通过实际体系烷基化反应活性评价和加速失活稳定性实验找出两种不同合成方法的β沸石在催化性能上的差异。并对工业失活和加速失活催化剂样品上沉积炭物种进行了分析，结果表明导致工业失活和加速失活的物质有相似之处。造成失活的主要物质均为二异丙苯的进一步反应产物——多环芳烃等物质，它们不易从孔道中传递出来，堵塞孔道，占据活性位，是造成失活的主要原因。由于两种不同β沸石的孔结构分布情况不同，对二异丙苯的进一步反应的产物的空间位阻和抑制作用不同，从而两样品的稳定性不同。F-β沸石的孔分布比W-β沸石合理，有较好的抑制炭物质生成的作用，故有较好的稳定性。

INFLUENCE OF ZEOLITE-β SYNTHESIZED BY DIFFERENT TEMPLATES ON ALKYLATION OF BENZENE WITH PROPYLENE

Samples (F-β and W-β) of zeolite-β synthesized by different templates were characterized by XRD, TPD and pore structure analysis. The differences of the zeolite-βsynthesized by two templates have been investigated through the activity evaluation of benzene alkylation reaction and the experiment of accelerated-aging. Coke composition on the deactivated catalysts used in industrial process and accelerated-aging experiment process was analyzed by MS-GC. The result shows that the two processes are similar in deactivation process of catalysts. Main coke materials are multi-aromatic hydrocarbons, which are deepening products of diisoproplbenzene alkylation. They can not diffuse from the pore of the zeolite easily, and block the pore path, and occupy the activity sites. Thus it makes the catalyst deactivated. Steric constraints during the formation of coke molecules are more pronounced in the relatively narrow cages than in the large cages. Because difference of pore distribution between F-βand W-βsamples, F-βsample has more the narrow cages (or more micropore) than W-βsample, and it has stronger steric constraint during deepening alkylation of disoproplbenzene than W-βsample, and lower coke is formatted on F-βsample. This reason results in better stability of the F-βsample. The pore structure data show that rational distribution of micropore in zeolite-βis very important to restrain producing of the coking materials. Different distribution of pore on zeolite-βis the main reason that makes F-βand W-βsamples have differences in the activity evaluation of alkylation reaction and stability of the accelerated-aging experiment.