Synthesis And Modification Of MCM-49 Zeolite

In this work, different conditions of synthesized MCM-49 zeolites have been investigated, and the optimal conditions concerned have been determined in 1L reactor. Phosphate-modified MCM-49 zeolites were prepared and were evaluated in the alkylation of IPB with benzene and propylene.The results revealed that MCM-49 zeolites with high degree of crystallinity can be synthesized by dynamic method rather than static method. The products were characterized by different techniques. The appropriate SiO2/Al2O3 ratio for synthesis of MCM-49 zeolite was 25. The increasing alkalinity was suitable for forming MCM-49 zeolites with a certain degree and the best OH-/SiO2 ratio was 0.18, in which case MCM-49 zeolite can be formed after 36h. When the crystallization temperature is higher than 150.0℃, the degree of crystallinity would be higher with increasing crystallization time, and the best crystallization time was 72h. High crystallization temperature was helpful to form MCM-49 zeolites, and the appropriate crystallization temperature was 170.0℃.The pore structure and the distribution of acid of MCM-49 zeolites can be adjusted by phosphate-modification. The amounts of strong acid decreased and the amounts of weak acid increased firstly and then decreased. When the phosphate mass fraction was 1.5%, the amount of weak acid was highest. The phosphate-modified blocked the pore structure of MCM-49 zeolite, and made both the surface area and pore volume decreased. Phosphate-modified MCM-49 zeolites enhanced the selectivity to IPB in benzene alkylation with propylene.