Studies On Complex Metal-Oxide For Catalytic Selective Oxidation Of Propane

Acrylic acid(AA)is a very important raw material in organic chemical industry. In the current commercial process, which is produced via a two-step selective oxidation process using propene as the starting material. Compared with propene two-step process, the one-step oxidation of propane to acrylic acid has much advantages, such as cheaper raw materials, shorter flow,　especially, it can take full advantage of alkane resource,　that it was widely concerned in recent years. Complex metal-oxide is one of the most potential catalysts at the present time, which has very excellent catalysis for the directly selective oxidation of propane to acrylic acid, and has been studied extensively in recent years. The effect of the metal element composition, the metal ratio of the complex metal-oxide catalysts and several parameters involved in preparing the complex metal-oxide catalysts (including mixing method, drying method,　calcination mode,　pH value and so on) on the catalytic performance were studied, and the best conditions were selected via evaluating the catalysts'performances. It was found that Mo V Te Nb four element are absolutely necessary for good catalyst, and the preferred metal ratio is around the vicinity of Mo_1.0V_0.3Te_0.23Nb_0.12. the preferred preparation method for an effective MoVTeNb oxide catalyst, includes the intimate mixing of all starting chemicals to form a precursor solution and keeping the pH value of the solution between 2³, dring via rotary evaporation method, followed by calcination under a non-flow nitrogen atmosphere at 600℃.　The reaction conditions of selective catalytic oxidation of propane were studied. The effects of the reaction temperature, the total space velocity, the O₂/C₃⁰ ratio of reating gas and the water content on the catalytic performance were investigated. As shown by the experiment result, the preferred reaction conditions were chosen as follows: reaction temperature -400℃;　total space velocity -1800h^-1; ratio of reating gas -C₃⁰/N₂/O₂=4.4/36.9/12.8; water content -15%. Under the fore-mentioned condition, the conversion of propane is 38.60%, the yield of AA reached 15.87%, the selectivity of AA is 41.11%.