Direct synthesis of propylene oxide using hydrogen peroxide in a membrane reactor

The epoxidation of propylene to propylene oxide (PO) with hydrogen peroxide was carried out in a titanium silicalite-1 (TS-1) catalytic membrane reactor. The TS-1 catalytic membrane with a thickness of 4–5 μm was fabricated on a tubular porous α-Al2O3 substrate. The structure and morphology of the membranes were characterized by scanning electron microscope, X-ray diffractometer, FT-IR, and a UV–vis spectrometer. Reaction conditions including temperature, pressure and H2O2 concentration were investigated for their effects on H2O2 conversion, PO selectivity and PO formation rate. The PO formation rate on the TS-1 catalytic membrane is more than twice as high as that on the TS-1 powder catalyst. Moreover, the regeneration tests of the TS-1 membrane reactor showed that the catalytic membrane kept relatively stable H2O2 conversion of and PO selectivity for eight reactions.