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Date of Publication:2022-10-09

Journal:催化学报

Affiliation of Author(s):化工学院

Volume:22

Issue:5

Page Number:465-468

ISSN No.:0253-9837

Abstract:Titanium silicalite TS-1 containing different amount of aluminum impurity was synthesized using tetrapropylammonium. bromide (TPABr) as the template and using colloidal silica as the silica source. The effect of aluminum impurity on the performance of titanium silicalite was systematically investigated. It was shown that a little amount of aluminum impurity can improve the crystallization of titanium silicalite, but some acid sites are introduced into the sample simultaneously. The acid sites originated from framework aluminum can catalyze the side reaction of propylene oxide (PO) with the solvent methanol in propylene epoxidation. If a small amount of base is added into the medium, the side reaction can be inhibited and the PO selectivity can increase significantly. But the excess base can deactivate the titanium silicalite TS-1 catalyst. The titanium silicalite catalyst exhibited excellent performance for propylene epoxidation both in the autoclave reactor and in the fixed-bed reactor. All of the criteria such as H2O2 conversion X(H2O2),H2O2 utilization efficiency U(H2O2) and PO selectivity S (PO) still kept above 90% when the time on stream in the fixed-bed reactor reached 200 h.

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