晶种数量对MOR分子筛上烷基转移反应的影响及反应机理研究

以丝光沸石(MOR)分子筛为催化剂,甲苯与三甲苯烷基转移反应为探针反应,系统考察了晶种数量变化对分子筛物化性能和催化性能的影响。研究表明,合成过程中晶种添加量的不同会显著影响催化剂的酸性、比表面积和孔体积,进而影响其催化剂活性和稳定性。当晶种添加量为8%时,MOR分子筛具有最多的B酸含量、最大的比表面积和孔体积,同时对应的催化剂活性和稳定性也最好。本研究还对甲苯和三甲苯烷基转移反应机理进行了深入研究,结果表明,发生在MOR分子筛上的烷基转移反应通过双分子中间体机理进行,并应用实验手段捕捉到了中间体的存在,证实了双分子中间体机理的合理性,同时推导出可能的反应机理路线图。

Effect of seed number of MOR zeolites on the transalkylation reaction and the investigation of the reaction mechanism

The effect of the number of crystal seeds on the physical and chemical properties and catalytic performance of the mordenite (MOR) zeolite was investigated using the transalkylation of toluene and trimethylbenzene as the probe reaction. The results show that the addition of seed crystals in the synthesis process will significantly affect the acidity, specific surface area and pore volume of the catalyst, thus affect the activity and stability of the catalyst. When the addition amount of crystal seeds is 8%, the MOR has the most B acid content, the maximum specific surface area and the pore volume, and the activity and stability of the catalyst are also the best. In addition, the mechanism of the transalkylation reaction of toluene and trimethylbenzene has been studied in detail. The results show that the transalkylation reaction in the MOR molecular sieve channels is carried out by the mechanism of bimolecular intermediates, and the intermediates, confirming the rationality of the mechanism of the bimolecular intermediates and deducing the possible reaction route.