摘要
Abstract
Propylene carbonate(PC)is widely used in battery and chemical industry.Urea alcoholysis to PC has a broad industrial application prospect with the features of cheap and easy-to-obtain raw materials,mild reaction conditions,etc.However,the commonly used metal oxide catalysts suffer from serious loss of active components and poor reproducibility,which severely limit the industrial development of urea alcoholysis method,so it is urgent to develop catalysts with both high activity and stability.MTiO3-type composite catalysts were prepared,and the effects of preparation conditions on the structures and catalytic performances for urea alcoholysis to PC of catalysts were studied by various characterization methods,such as TGA-DSC,XRD,SEM,etc.,and the reaction conditions were optimized.The results show that MgTiO3-750 calcined at 750℃ shows the best catalytic activity.Under the conditions of reaction temperature of 170℃,reaction time of 3 h,n(1,2-propanediol)∶n(urea)=1.5∶1.0 and catalyst's mass fraction of 1％,the PC yield reaches 91.2％.The PC yield maintains from 80.0％to 90.0％catalyzed by MgTiO3-750 reused five times under the same conditions.The composite catalyst MgTiO3+ZnO was further constructed.It is found that through the synergistic effect of medium-strong base sites in MgTiO3+ZnO,the PC yield increases to 95.7％under the same reaction conditions.What's more,the PC yield still exceeds 91.0％catalyzed by MgTiO3+ZnO reused multiple times.The catalytic activity can be restored by supplementing ZnO for regeneration treatment.关键词
溶胶凝胶法/MTiO3型复合催化剂/尿素醇解/碳酸丙烯酯Key words
sol-gel method/MTiO3-type composite catalysts/urea alcoholysis/propylene carbonate分类
化学化工
