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摘要: 采用丙烯气相进料，在预混段中先与双氧水的甲醇溶液混合后进入固定床反应器，考察了进料液中pH值、丙二醇单甲醚、乙硫醇以及铁锈等对丙烯环氧化连续反应中TS-1分子筛催化剂性能的影响。结果表明，进料液体pH值对催化剂的催化性能有影响，适宜的进料液体pH值在7左右；副产物丙二醇单甲醚含量的增加不会对催化剂性能产生影响；乙硫醇量的增加使环氧丙烷选择性下降，但不会引起催化剂的失活；而进料液体中铁锈的引入会导致催化剂中部分孔堵塞，使催化剂部分失活。当进料液中的pH值用0.1mol/L的氨水调节为7左右，在反应温度55℃,反应压力0.7MPa，TS-1催化剂具有较好的稳定性，经130h的连续试验考察，双氧水的转化率和环氧丙烷的选择性约为90%。Abstract: 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.
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Key words:
- propene /
- epoxidation /
- titanium silicalite /
- catalyst deactivation /
- stability /
- propylene oxide
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