The Study Of The Synthesis Of MCM-22 Zeolite And Its Catalytic Property Of Benzene Reaction With Propene

MCM-22 zeolite was synthesized with hexamethylenimine as template, by hydrothermal motional crystallization method. The effects of aging temperature, crystallization temperature and time, Si/Al ratio on crystal structure and acidity of MCM-22 was studied. Results show that MCM-22 zeolite partially transformed to ZSM-35 with prolonging the reaction time(≥7days), crystallinity was increased by increasing the aging temperature. When the crystallization temperature is low, the grow of crystal is slow, the crystallization time with high crystallinity is prolonged. Decreasing n(SiO2)/n(Al2O3) resulted in the formation of mordenite. The total acid amount of MCM-22 zeolite was increased gradually with increasing n(SiO2)/ n(Al2O3), the B and L acid amount of MCM-22 both increased correspondingly, the change of B acid was little and the increase of L acid amount was high.The effects of n(SiO2)/n(Al2O3), reaction temperature, n(C6H6)/n(C3H3), WHSV(C3H6) on the distribution of products was investigated by use of continuous and semi-continuous reaction. Results show that the relation between activity of MCM-22 over benzene alkylation with propylene and L acid is little, but the activity of MCM-22 has relation with its B acid amount. With increasing n(SiO2)/n(Al2O3), the B acid amount of MCM-22 is increased, the catalytic activity of MCM-22 zeolite is increased too. When the n(SiO2)/n(Al2O3) is equal to 40, the selectivity of cumene is the highest, and the amount of Di-isopropylbenzene and Triisopropylbenzene in cumene is the lowest, however, the amount of n-propylbenzene is the highest, this is because the ratio of B acid is the highest. The selectivity of cumene increased with increasing temperature, the content of n-propylbenzene increased and oligomers decreased. High B/P ratio is favor to purpose product. The change of space velocity (referred to propylene) has little influence on the selectivity of products. With increasing reaction time, the selectivity of cumene and oligomers is increased, and the selectivity of di-isopropylbenzene and tri-isopropylbenzene is decreased.The acidity, pore structure and catalytic properties ofβand MCM-22 zeolites were compared by means of FTIR spectra, TG , N2 sorption and reaction characterization. Results show that both the acidities and pore structures have great effects on the catalytic properties. The total acid and B acid sites ofβzeolite are...