Propene-V 2O 2 interactions studied by infrared emission spectroscopy

Abstract

Infrared emission spectroscopy was used to investigate the interactions between propene and vanadium hemipentoxide. The spectrum obtained for V 2O 5 alone was very similar to the spectrum given by KBr disc transmission method. Reaction of propene on V 2O 5 was performed between 110 and 250°C; IR spectra were recorded in situ. Reduction of the oxide occurred and its bands were strongly altered. The bands attributed to the terminal oxygen (1018 cm −1) and to the doubly bridged oxygen (820 cm −1) were mainly affected by the reaction with propene. For a reaction temperature of 250°C, the recorded spectrum was close to that given by hydrogen reduction at 230°C. It can be concluded that V 2O 5 was reduced by propene with the formation of a superficial suboxide. By oxygen treatment, the reduced form was restored to the initial V 2O 5 sample. Infrared emission spectroscopy appears as a very suitable method for studying the interactions of the reactants with the catalysts.