Synthesis Of Titanium Silicalite-1 With Cheap Materials

In this paper, Titanium Silicalite-1 (TS-1) was synthesized by using tetrapropylammonium bromide as cheap template by hydrothermal method. Using silica gel containing different impurities as Si source to synthesize TS-1 with different Si/Ti ratios in the both static and stirring autoclaves. Synthesis conditions were investigated on effect of the synthesis and catalytic performance, such as Si/Ti ratios, impurities contents of sodium and aluminum, heating rate, stirring rate, volume of the autoclave and seeds. The samples were characterized by using XRD, SEM, UV-Vis, IR, and catalytic performance for propylene epoxidation. The following results have been obtained:1. TS-1 with different Si/Ti ratios was synthesized by different silica gel in the static autoclave. The results show that relative crystallinity remains unchanged, crystal size decreases and extra-framework Ti species decreases with Si/Ti ratios increasing in the same silica gel. The impurities in silica gel reduce the crystallinity of TS-1, and inhibite titanium into framework. The Si/Ti ratio of TS-1 synthesized by silica gel A with the least impurities is 130, H2O2 conversion is above 95%, and the PO selectivity is 43.5%.2. TS-1 was synthesized in the srirring autoclave. The results show that synthesis conditions including heating rate, stirring rate and volume of the autoclave less affect crystal morphology of TS-1. While Faster stirring rate can inhibit the formation of extra-framework titanium, and catalytic activity of TS-1 synthesized with 450r/min stirring rate is best.3. TS-1 was synthesized with seed inheritance. With times of synthesis increasing, TS-1 with larger crystal size can be obtained, crystallization rate becomes slower, framework Ti species decrease, the contents of extra-framework Ti species increase, and catalytic activity reduce for propylene epoxidation.