Abstract: The SnO2-Nb2O5/MgAl2O4/α-Al2O3 catalyst was prepared by modification of α-Al2O3 with MgAl2O4 along with the doping of SnO2 in Nb2O5 and used for hydration of ethylene oxide (EO) to monoethylene glycol (MEG). The effects of Sn/Nb molar ratios on the structure, the acidity and the catalytic performance of the catalyst were investigated by using X-ray diffraction, infrared spectroscopy, temperature-programmed desorption of NH3 and of EO. The phase composition of niobium species, the catalyst acidity, and the adsorption states and strength of EO were markedly influenced by the Sn/Nb molar ratios, leading to different EO conversion and MEG selectivity. MEG selectivity of 95.2% was achieved at n(Sn)/n(Nb)=0.8. The characterization of the used catalyst revealed that no obvious change was recorded, indicating the good hydrothermal stability of the catalyst.

Key words: niobium oxide, alumina, stannic oxide, magnesia-alumina spinel, ethylene oxide, hydration, monoethylene glycol