The catalysts of nanometer TiO 2/BuOH and hydrous TiO 2 were prepared by the liquid phase method from Ti(SO 4) 2. The properties of the catalysts were characterized by TG DTA, IR, XRD, TEM methods. The results showed ...The catalysts of nanometer TiO 2/BuOH and hydrous TiO 2 were prepared by the liquid phase method from Ti(SO 4) 2. The properties of the catalysts were characterized by TG DTA, IR, XRD, TEM methods. The results showed that nanometer TiO 2/BuOH was anatase particles with 10 nm×20 nm. The main product in styrene epoxidation with t butyl hydroperoxide(TBPH) was styrene epoxide, by product was phenylformaldehyde under the condition of 80 ℃ for 6 h. Hydrous TiO 2 prepared below 260 ℃ was non crystal powder and converted into anatase particles with 10 nm×300 nm when it was roasted at 500 ℃ . The catalytic activity of 10 nm×300 nm anatase particles had only 50% that of particles with 10 nm×20 nm. The centers of acid on the catalyst surface made the epoxide selectivity decrease obviously. The order of the influence of solvent on epoxidation reaction: 1,2 dichloroethane>butanol>cyclohexanone>methyl cyclohexane>cyclohexanol>acetic acid.展开更多
The nanometer TiO 2 and nanometer TiO 2/EtOH catalysts were prepared from Ti(SO 4) 2 by the liquid phase method. The properties of these catalysts were characterized using TG DTA, IR, XRD and TEM methods.. The results...The nanometer TiO 2 and nanometer TiO 2/EtOH catalysts were prepared from Ti(SO 4) 2 by the liquid phase method. The properties of these catalysts were characterized using TG DTA, IR, XRD and TEM methods.. The results show that both TiO 2 and TiO 2/EtOH are anatase with the particle sizes of about 60 nm possessing excellent thermal stability. The activities and selectivities of catalysts in styrene epoxidation with t butyl hydroperoxide (TBPH) were examined and the influence of different solvents on catalytic performance was examined. When the oxidation is carried out under suitable conditions, the main product and byproduct are styrene peroxide and phenylformaldehyde, respectively. The conversion of styrene and selectivity to epoxide over nanometer TiO 2/EtOH catalyst are 34.7% and 60.0% , respectively. When cyclohexanone or 1,4 dioxane are used as solvents, the selectivity to epoxide is more than 70%. The ethanol supported nanometer TiO 2 improved the activity obviously and the suitable solvents increased the selectivity to epoxide.展开更多
The catalyst of nanometer Ag supported on nanomter TiO 2 particles was synthesized by irradiating TiO 2 colloid containing AgNO 3 solution.Its properties were characterized by IR,TEM,XRD,and BET methods.The size of ca...The catalyst of nanometer Ag supported on nanomter TiO 2 particles was synthesized by irradiating TiO 2 colloid containing AgNO 3 solution.Its properties were characterized by IR,TEM,XRD,and BET methods.The size of catalyst particles was 12 1nm,composed by 95% TiO 2 and 5% Ag.The experimental results showed that the catalyst of nanometer Ag supported on nanometer TiO 2 improved obviously the activity and selectivity in the epoxidation of styrene.展开更多
Liquid-phase epoxidation of styrene with atmospheric O_2 was conducted over CoAPO-5 molecular sieves.The catalytic performance of CoAPO-5 can be significantly improved by alkali metal salt impregnated on it,and styren...Liquid-phase epoxidation of styrene with atmospheric O_2 was conducted over CoAPO-5 molecular sieves.The catalytic performance of CoAPO-5 can be significantly improved by alkali metal salt impregnated on it,and styrene conversion and selectivity to styrene oxide reached 85%and 69%respectively when CsCl was impregnated on it.The catalyst was recyclable and exhibited similar catalytic activity and selectivity even after three catalytic reaction cycles.展开更多
文摘The catalysts of nanometer TiO 2/BuOH and hydrous TiO 2 were prepared by the liquid phase method from Ti(SO 4) 2. The properties of the catalysts were characterized by TG DTA, IR, XRD, TEM methods. The results showed that nanometer TiO 2/BuOH was anatase particles with 10 nm×20 nm. The main product in styrene epoxidation with t butyl hydroperoxide(TBPH) was styrene epoxide, by product was phenylformaldehyde under the condition of 80 ℃ for 6 h. Hydrous TiO 2 prepared below 260 ℃ was non crystal powder and converted into anatase particles with 10 nm×300 nm when it was roasted at 500 ℃ . The catalytic activity of 10 nm×300 nm anatase particles had only 50% that of particles with 10 nm×20 nm. The centers of acid on the catalyst surface made the epoxide selectivity decrease obviously. The order of the influence of solvent on epoxidation reaction: 1,2 dichloroethane>butanol>cyclohexanone>methyl cyclohexane>cyclohexanol>acetic acid.
文摘The nanometer TiO 2 and nanometer TiO 2/EtOH catalysts were prepared from Ti(SO 4) 2 by the liquid phase method. The properties of these catalysts were characterized using TG DTA, IR, XRD and TEM methods.. The results show that both TiO 2 and TiO 2/EtOH are anatase with the particle sizes of about 60 nm possessing excellent thermal stability. The activities and selectivities of catalysts in styrene epoxidation with t butyl hydroperoxide (TBPH) were examined and the influence of different solvents on catalytic performance was examined. When the oxidation is carried out under suitable conditions, the main product and byproduct are styrene peroxide and phenylformaldehyde, respectively. The conversion of styrene and selectivity to epoxide over nanometer TiO 2/EtOH catalyst are 34.7% and 60.0% , respectively. When cyclohexanone or 1,4 dioxane are used as solvents, the selectivity to epoxide is more than 70%. The ethanol supported nanometer TiO 2 improved the activity obviously and the suitable solvents increased the selectivity to epoxide.
文摘The catalyst of nanometer Ag supported on nanomter TiO 2 particles was synthesized by irradiating TiO 2 colloid containing AgNO 3 solution.Its properties were characterized by IR,TEM,XRD,and BET methods.The size of catalyst particles was 12 1nm,composed by 95% TiO 2 and 5% Ag.The experimental results showed that the catalyst of nanometer Ag supported on nanometer TiO 2 improved obviously the activity and selectivity in the epoxidation of styrene.
基金supported by the National Natural Science Foundation of China(No.20971095)the Science Foundation of Shanxi Province(No.2010011014-4)the Foundation for Returned Overseas Scholars of Shanxi Province(No.2008-10)
文摘Liquid-phase epoxidation of styrene with atmospheric O_2 was conducted over CoAPO-5 molecular sieves.The catalytic performance of CoAPO-5 can be significantly improved by alkali metal salt impregnated on it,and styrene conversion and selectivity to styrene oxide reached 85%and 69%respectively when CsCl was impregnated on it.The catalyst was recyclable and exhibited similar catalytic activity and selectivity even after three catalytic reaction cycles.
