Liquid-Phase Epoxidation Of Propene To Propy Lene Oxide Catalyzed By Titanium Silicalite

Titanium silicalite (TS-1) has been shown to be an efficient catalyst for the epoxidation of propene with hydrogen peroxide as oxidant. This reaction has many advantages, such as mild reaction conditions, high reaction rate, high selectivity, no pollution. In recent years, the epoxidation of propene has been investigated to some extent and proved to be a clean and economically viable alternative to replace the existing processes for propene oxide production.In this work,TS-1was hydrothermally synthesized with tetraethyl orthosilicate using as Si source,tetrabutyl titanate using as Ti source and tetrapropyl ammonium hydroxide as template. The structure and morphology of TS-1were characterized by XRD, UV-Vis, FI-IR and TEM, etc. The catalytic properties of TS-1are investigated for the reaction of propylene epoxidation.The optimization of reaction conditions for catalytic epoxidation of propylene by TS-1was studied in a slurry bed reactor using hydrogen peroxide as oxidant and methanol as solvent. For the first time, propylene oxide concentration as investigation index of catalyst performance in the reaction system.Under the optimal conditions:1.5g TS-1,150mL methanol,25mL30wt.%H2O2,55℃,0.2MPa, reaction time1h,1L/min propylene,500r/min, the utilization efficiency of H2O2is88.8%, the conversion of H2O2is94.4%, the selectivity and yield of propylene oxide are98.7%and87.6%, Mass concentration propylene oxide amounted to8.6%, particllarly.The propylene epoxidation of continuous reaction was carried out in a slurry bed reactor. The stability of preparation of TS-1catalyst was examined. Under the optimal conditions, TS-1catalyst can run stably for160h, the utilization efficiency of H2O2is83.4%, the conversion of H2O2is90.3%, the selectivity and yield of propylene oxide are99.6%and83.4%, mass concentration propylene oxide is up to8.1%,respectively. The reaction results reach the requirements of a pilot scale test.