液相法光催化氧化丙烯制环氧丙烷工艺条件的优化

Optimization of the Operating Conditions in the Process of Photo-catalysis Oxidation of Propylene to Propylene Oxide in the Liquid Phase

采用正交实验方法考察了液相法光催化氧化丙烯合成环氧丙烷中诸可控因素——乙醇与水体积比、氧气流速和单位体积催化剂用量对环氧丙烷液相浓度和选择性的影响,并对其工艺条件进行了优化。实验结果表明:对于液相环氧丙烷含量,因素乙醇与水体积比作用高度显著,因素氧气流速显著;对于环氧丙烷的选择性只有氧气流速作用显著;单位体积催化剂用量对环氧丙烷液相浓度和选择性影响不显著;最佳工艺条件为乙醇与水体积比2:1,氧气体积流量22.5mL/min和单位体积催化剂质量浓度2.0g/L,此条件下20W紫外灯照射3h得环氧丙烷液相浓度0.0293mol/L,而选择性和收率分别为72.70％和57.52％。

Orthogonal experiment method was used to investigate the influence of the adjustable factors (the volume ratio of ethanol to water, oxygen velocity and catalyst amount used per volume ) on the liquid concentration and selectivity of epoxy propane in the process of photo-catalysis oxidation of propylene to propylene oxide (PO) in the liquid phase. The results of experiments showed that for the factor C2H5OH : H2O (volume ratio) O2 flow rate is highly significant and significant respectively for PO concentration, only O2 flow rate is significant for PO selectivity, and the catalyst amount used per litter has little effect for either respect. The optimized operating conditions are C2H5OH :H2O (volume ratio) 2 : 1, O2 flow rate 22.5 mL/ min. and TiO2 powder 2.0 g/L, which gave PO concentration 0. 029 3 mol/L, selectivity 72.70% and yield 57. 52% respectively after the solution was illuminated under 20 W UV light for 3 hours.