화학공학소재연구정보센터
Applied Catalysis A: General, Vol.263, No.1, 83-89, 2004
Influence of calcination temperature and preparation method of TiO2-ZrO2 on conversion of cyclohexanone oxime to epsilon-caprolactam over B2O3/TiO2-ZrO2 catalyst
The effects of calcination temperature and preparation method of TiO2-ZrO2 mixed oxide on catalytic performance of B2O3/TiO2-ZrO2 catalysts were investigated. TiO2-ZrO2 mixed oxides with the same molar ratio of 1:1 were prepared by co-precipitation method, homogeneous precipitation method, sol-gel method and physical mixing method; each oxide was calcined at a temperature between 110 and 700degreesC. Catalytic synthesis of E-caprolactam from cyclohexanone oxime was evaluated in a fixed-bed flow microreactor at 300degreesC and atmosphere pressure. Characterization of catalysts was carried out using adsorption of nitrogen, X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR) and temperature-programmed desorption of ammonia (NH3-TPD) techniques. The experimental results reveal that the calcination temperature in the range of 110-500degreesC had only a slight effect on the catalytic performance, but after calcination at 700degreesC, the ZrTiO4 crystallite was formed and accounted for the decrease of acidity and catalytic performance. The co-precipitation method provided the catalyst with the highest reactivity while the physical mixing method resulted in the worst catalyst. Catalytic performance of the B2O3/TiO2-ZrO2 catalyst was closely related to its acid strength distributions and pore size. (C) 2003 Published by Elsevier B.V.