Methane oxidation over a V2O5 catalyst in the liquid phase

The selective oxidation of methane by V2O5 catalysts in oleum has been studied. The effects of the reaction temperature, the concentration of V2O5, and the residence time on the conversion of methane and the yield of methanol were investigated. We have found that methane was transformed to methyl bisulfate first, and the methyl bisulfate was then hydrolyzed to methanol. The process of the selective oxidation of methane was involved in electrophilic alternative mechanisms by V2O5 catalysts, and the sulfur trioxide in oleum was necessary for the reaction systems. The methane oxidation reaction was determined to be a first-order reaction, based on the pressure-time relationship. The maximum methanol yield of 45.5% and the methane conversion of 54.5% were obtained at a V2O5 concentration of 0.0175 mol, a reaction temperature of 453 K, a methane pressure of 4.0 MPa, a reaction time of 2 h, and the sulfur trioxide content in oleum is similar to 50%.