1-Butylene epoxidation was catalyzed by microporous titanosilicate molecular sieves TS-1 synthesized by different methods and mesoporous titanosilicate molecular sieves Ti-HMS, using dilute hydrogen peroxide solution ...1-Butylene epoxidation was catalyzed by microporous titanosilicate molecular sieves TS-1 synthesized by different methods and mesoporous titanosilicate molecular sieves Ti-HMS, using dilute hydrogen peroxide solution as oxidant. The effect of the Si/Ti molar ratio of the catalyst TS-1 and Ti-HMS on their performance was investigated. Conventional TS-1 has smaller crystal size and higher activity than that of TS-1 synthesized by using TPABr as template or the method of gas-solid phase. The TS-1 synthesized by using TPABr as template exhibits the highest selectivity to 1, 2-epoxybutane （BO）. With the increase of Ti content in molecular sieves, the conversion of H2O2 increases. The catalytic activity of mesoporous Ti-HMS is lower than that of TS-1, and large amount of H2O2 is decomposed in 1-butylene epoxidation. The primary reason for low activity of Ti-HMS in 1-butylene epoxidation is that Ti-HMS has poorer hydrophobicity property than TS-1.展开更多
Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-...Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-ray diffraction, N2 adsorption-desorption, Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, and ultraviolet-visible spectroscopy. The use of the colloidal seed reduced the crystal size, and an appropriate amount of silicalite-1 seed assisted Ti incorporation into the TS-1 framework. This method reduces the cost of TS- 1 synthesis because a significantly smaller amount of tetrapropylammonium hydroxide is used. The catalytic performance of the synthesized small-crystal TS-1 samples in cyclohexanone ammoximation was better than that of bulk TS-1 as a result of improved diffusion and a larger number of active tetrahedral Ti centers.展开更多
文摘1-Butylene epoxidation was catalyzed by microporous titanosilicate molecular sieves TS-1 synthesized by different methods and mesoporous titanosilicate molecular sieves Ti-HMS, using dilute hydrogen peroxide solution as oxidant. The effect of the Si/Ti molar ratio of the catalyst TS-1 and Ti-HMS on their performance was investigated. Conventional TS-1 has smaller crystal size and higher activity than that of TS-1 synthesized by using TPABr as template or the method of gas-solid phase. The TS-1 synthesized by using TPABr as template exhibits the highest selectivity to 1, 2-epoxybutane （BO）. With the increase of Ti content in molecular sieves, the conversion of H2O2 increases. The catalytic activity of mesoporous Ti-HMS is lower than that of TS-1, and large amount of H2O2 is decomposed in 1-butylene epoxidation. The primary reason for low activity of Ti-HMS in 1-butylene epoxidation is that Ti-HMS has poorer hydrophobicity property than TS-1.
基金supported by the National Natural Science Foundation of China(21403070 and 21373088)Innovation Program of Shanghai Municipal Education Commission(13zz038)+2 种基金Key Project of the Shanghai Committee of Science and Technology(12JC1403600)National Key Technology R&D Program(2012BAE05B02)Shanghai Leading Academic Discipline Project(B409)~~
文摘Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-ray diffraction, N2 adsorption-desorption, Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, and ultraviolet-visible spectroscopy. The use of the colloidal seed reduced the crystal size, and an appropriate amount of silicalite-1 seed assisted Ti incorporation into the TS-1 framework. This method reduces the cost of TS- 1 synthesis because a significantly smaller amount of tetrapropylammonium hydroxide is used. The catalytic performance of the synthesized small-crystal TS-1 samples in cyclohexanone ammoximation was better than that of bulk TS-1 as a result of improved diffusion and a larger number of active tetrahedral Ti centers.
