Effect Of Modified And Extruded Titanium Silicalite-1on Catalytic Performance In Gas Phase Epoxidation Of Propylene

In this paper, taken TS-1with different crystal size as parent, we systematically studied the effects of treatment by different alkali solutions(TPAOH, KOH, NaOH, TPABr/KOH and TPABr/NaOH)and extrusion mouldingon the catalytic performance of TS-1in gas phase propylene epoxidation. And we also studied the influence of alkali treatment and extrusion moulding on the mechanical strength of TS-1. All TS-1samples were characterized by SEM, XRD, UV-Vis, FT-IR, N2adsorption and mechanical strength. The results and conclusions were as follows:1. The topology framework of five TS-1samples with different crystal size after modification was maintained. Compared with TS-1without treatment, the catalytic performance of all treated samples was more or less improved in gas phase propylene epoxidation.The selectivity of propylene oxide was all more than90%.2. Compared with other solutions, KOH solution and TPABr/KOH solution to enhance the catalytic performance of TS-1are more obvious. Especially, for TS-1with small crystal size treated by TPABr/KOH solution, the propylene conversion and propylene oxide selectivity were increased to6.3%and92.3%.3. For extruded TS-1samples, there is no obvious influence on catalytic performance for TS-1before or after forming in gas phase propylene epoxidation. Compared with TS-1without treatment, the mechanical strength of treated TS-1was improved. For extruded TS-1treated by KOH, propylene conversion was5.6%, propylene oxide selectivity was98%, while the mechanical strength was the highest10.5N/mm.4. For extruded TS-1catalyst, the treatment by TPAOH solutions of different concentrations all can largely improve the mechanical strength of the catalyst. But the extruded TS-1catalyst treated by TPAOH solutions are different degrees of decline.