Esterification of acetic acid with n-Butanol using vanadium oxides supported on γ-alumina

摘要

Esterification of acetic acid with n-Butanol has been studied in a heterogeneous reaction system using two 7-alumina-supported vanadium oxide catalysts with different V loadings, which were prepared by the impregnation of a precipitated alumina. The alumina support and the supported catalysts were characterized using X-ray diffraction, N2 adsorption, EDX analysis and NH3-TPD techniques. The effects of the reaction time, of the molar ratio of the reactants, of the speed of agitation and of the mass fraction of the catalyst on the catalytic properties were studied. In the presence of the supported catalyst containing 10 wt % V2O5 (10V-A12O3 sample) the conversion reached 87.7% after 210 min of reaction at 100 °C with an n-Butanol-to-acetic acid mole ratio equal to one. The conversion as well as the total acidity measured by TPD of NH3 increased in the following order: A12O3 < 5V-A12O3 (5wt % V2O5/Al2O3)<10V-Al2O3. In all cases the reaction was completely selective to n-butyl acetate. Nevertheless, a loss in catalytic activity after three reaction cycles with 10V2O5-Al2O3 catalyst was observed.