The catalytic synthesis of p-nitrobenzoic acid (PNBA) by oxidation of p-nitrotoluene with potassium permanganate (KMnO4) in the presence of phase transfer catalyst (PTC,PEG—600) are reported. The effects of different factors, such as amount of PEG—600, reaction temperature and time, amount of potassium permanganate, and basicity and acidity of reaction system, on the yield of PNBA were investigated. Under the optimal reaction conditions, molar amount of PEG—600, 5%, molar ratio of KMnO4 to PNT, 3∶1, reaction temperature, 95℃, reaction time, 3 h, the yield of PNBA was 51-6% in neutral reaction system. The experiment results show that PEG—600 is a good PTC for the synthesis.

PEG—600; phase transfer catalysis; p-nitrotoluene; p-nitrobenzoic acid; potassium permanganate (KMnO4); organic synthesis