Improved synthesis in preparation of benzaldehyde from toluene

Benzaldehyde was obtained via oxidation of toluene by MnO2 in H2SO4 solution using benzoic acid as the phase transfer catalyst.The influence of H2SO4 concentration,reaction temperature and dosage of benzoic acid on reaction rate and yield of benzaldehyde was investigated by orthogonal experiment.And the results showed that the optimum conditions were as follows:0.215 4 g of benzoic acid was dissolved in a solution composed of 40 mL of 58% H2SO4 and 10 mL of toluene.The yield of benzaldehyde was 42% based on the weight of MnO2 when toluene reacted with MnO2 at 75 ℃.