Partial Oxidation of Propane Over V—P—O Catalysts and Promoters

Over the catalyst containing (VO)₂P₂O₇ and β∗-VOPO₄, C₃H₈ was oxidized to acetic and acrylic acids with the selectivities of 30∼36% and 30∼38%, respectively. The addition of La₂O₃ and Dy₂O₃ onto the catalyst brought about an increase in the rate of carboxylic acids formation and its selectivity. The formation rate of the carboxylic acids gave a maximum at 10—20 at% of La content. Enhanced selectivity of carboxylic acids was observed upon the addition of Bi₂O₃. The selectivity of acetone extraporated to 0 sec of W/F was estimated to about 6%, suggesting that there is a reaction path to acetone via isopropenyl radical, isopropenylperoxyl radical. Temperature programmed desorption spectra of NH₃ and C0₂ from the V—P—O catalysts with and without La₂O₃ indicated that the addition of La₂O₃ increased the amount of both weaker acidic sites and weaker basic sites. Comparing the formation rates of partial oxidation products over the La₂O₃ containing catalyst and that containing no La₂O₃ in the oxidation of C₃H₈, C₃H₆, and acrylic acid, it is concluded that added La₂O₃ mainly accelerates the rate of reaction via isopropenylperoxyl radical.