丙烯环氧化反应中TS-1催化剂失活研究

The effects of pH value of liquid feed as well as the presence of monomethyl ether (MME), ethyl thiol and rust in the feed on the catalytic performance of TS-1 in propene epoxidation were investigated, where the epoxidation was carried out in a continuous fixed-bed reactor and gaseous propene was pre-mixed with dilute solution of hydrogen peroxide in methanol. It was shown that the presence of MME in feed has no impact on the catalytic performance of TS-1. The addition of ethyl thiol in the feed exhibits little effect on the catalytic activity, but may cause a decrease in propylene oxide (PO) selectivity. The pH value of liquid feed influences the catalytic performance significantly; an optimum pH value is about 7. The rust in the feed may block the pores of TS-1 and then cause a partial deactivation. With a liquid feed pH value of 7 (adjusted with 0.1mol/L ammonia water), the catalyst TS-1 exhibits excellent stability at 55℃ and 0.7MPa; both H2O2 conversion and PO selectivity exceeded 90% in a 130h catalytic test.