Research On MoVTeNbO Catalyst Prepared Using TeO₂ As Te Source

More and more attention has been paid to selective oxidation of propane to acrylic acid since the technology of n-butane selective oxidation to maleic anhydride has been widely used. However, propane is more chemical satble than butane and compare with maleic anhydride, the aimed product acrylic acid is more reactive, leading to the selective and yield in oxidation of propane to acrylic acid are quite lower. That is the reason why propane selective oxidation to acrylic acid is more difficult in thermodynamics. Only by the effective catalyst may obtain high yield. Complex metal oxides catalyst is one of the most potential catalyst at present, which have good performance in the catalytic selective oxidation of propane to acrylic acid, and has been studied extensively in recent years.In this paper, the preparation of the complex metal oxides catalyst Mo_1.0V_0.3Te_0.23Nb_0.12O_n used TeO₂ as Te source. It was carried out in a mini-fixed bed reactor in which the feeding gas was supplied successively, which focused on the preparation procedure at the formation of the catalyst active phase. Comparison of rotation stirring, magnetic stirring and ultrasonic vibration, the third method could achieve a high degree of dispersion components, and the hydration reaction temperature and time had some influences on the three components of MoVTe and the four components of MoVTeNb during the preparation. The best catalyst performance was when the pH value of the solution presented 2.0².8, and not suitable to add CTAB and PVA. BET results of the products indicate that microwave drying were helpful in getting the larger surface area, and choose nitrogen-stoppage calcination at 300℃-room temperature-600℃can get active phase. The experiment results showed that the proper reaction conditions were as follows: the reaction temperature was 400℃, the gas hourly space velocity was 800h-1, and the ratio of oxygen to propane was 2:1. Under this condition, the yield of AA reached 15.7%. The catalytic performance is quite stable during the 96 hours on stream, and the propane conversion remained about 45%, acrylic acid yield around 15%.