P-nitrobenzoic acid is a yellow-white crystal. It is soluble in ethanol, ether, chloroform, acetone and boiling water, slightly soluble in benzene and carbon disulfide, and insoluble in petroleum ether. It is used to synthesize procaine, procaine amide, p-aminobenzoic acid, folic acid, etc. It is also widely used to synthesize pesticides and fuels. It is obtained by oxidation of p-nitrotoluene. The oxidant can be sodium dichromate, air, manganese ore powder, nitric acid, etc. Using p-nitrotoluene as raw material, in the presence of sulfuric acid, the oxidation reaction was carried out at 55 ℃ with sodium dichromate to produce p-nitrobenzoic acid.