화학공학소재연구정보센터
Catalysis Today, Vol.297, 316-323, 2017
Synthesis of titanium containing MCM-41 from industrial hexafluorosilicic acid as epoxidation catalyst
The industrial by-product hexafluorosilicic acid was investigated as silicate source for titanium containing MCM-41 (Si/Ti-MCM-41) synthesis. An extended and detailed study, which includes the effects of several factors such as the state and content of Ti, surfactant/Si ratio and template removal technique on the physicochemical properties and catalytic activity of Si/TiMCM-41, is presented; The Si/TiMCM-41 was also characterized by powder X-ray diffraction, N-2 adsorption-desorption, fourier transform infrared spectroscopy, ultraviolet-visible spectrophotometer, thermal gravimetric measurements, X-ray fluorescence and scanning electron microscopy. The results show that the specific surface area and pore volume of the molecular sieve reach 1040 m(2) g(-1) and 0.74 cm(3) g(-1) under the hydrothermal conditions of the Si/Ti mole ratio equal to 60, CTAB/Si mole ratio to 0.81, hydrothermal temperature at 343 K and time for 3 h. The catalytic performance shows that samples have higher activity and selectivity for cyclohexene epoxidation to produce cyclohexene oxide. With the reaction temperature 333 K and mole ratio of cyclohexene/tertiary butyl peroxide hydrogen equal to 1, the highest cyclohexene conversion and epoxide selectivity is 79.23% and 95%, respectively. The catalyst activity has not obvious change with two times recycles. (C) 2017 Elsevier B.V. All rights reserved.