Selective Oxidation Of Propane To Maleic Anhydride And Acetic Acid

Propane is produced in large amount in natural gas and petroleum processing. It is an easily found chemical in chemical industry. However, since propane has high stability, it does not react with strong acid, strong base, oxidants, and reductants at regular conditions. Therefore, propane is not widely used in synthesis chemistry. Currently, propane is directly used as fuel. It is desired to convert propane to high value hydrocarbons or oxygenates.In our investigation of propane selective oxidation, a new catalytic reaction was discovered. Through this reaction, propane was efficiently converted to maleic anhydride and acetic acid over a type of VMoO catalysts and metal-ion-doped VMoO catalysts. Over 70%Mo20%V10%AgO catalyst, 37.4% of propane single pass conversion with maleic anhydride selectivity of 53.6% and acetic acid selectivity of 38.9% was obtained at 300℃. Only little amount of CO_x and acrylic acid were produced in the reaction.The selective oxidation of propane was performed in a glass tube fixed-bed reactor. In each reaction, 2.00 g catalyst (40-60 mesh) was employed. Reactions were performed at atmospheric pressure in the temperature range of 280—360℃with desired molar ratio of propane to oxygen. In this work, we have investigated the influences of catalysts, the ratio of propane to oxygen, and the reaction temperature on product distribution. Meanwhile, we have compared 3 different kinds of catalyst preparation methods to optimize the catalysts.In the current work, that maleic anhydride and acetic acid were formed as major products in propane oxidation revealed that the propane oxidation over our VMoO catalyst or metal-ion-doped VMoO catalyst did not follow the regular propane oxidation mechanisms reported in literatures. In the reported work, propene, acrylic acid, and acrolein were reported to be the main products. Based on the investigations, either the skeleton carbon-carbon bond cracking-recombination pathway or dimerization-cracking pathway might be the typical reaction model. In practice, the reaction is potentially useful in converting propane to high value maleic anhydried and acetic acid.