The invention discloses a method for co-producing
benzoic acid, p-toluylic acid and m-methylbenzoate. The method comprises the following steps of (1) oxidizing: adding a
xylene mixture, a catalyst and an
oxygen-containing gas into an oxidation reactor to react, wherein the content of
oxygen in the
oxygen-containing gas in percentage by
mass is no less than 15%; (2) gas and liquid separating and purifying: sending an oxidation reaction liquid into a gas and liquid separator, condensing and separating a
gas phase part, circulating the condensate into the oxidation reaction liquid to continue to
oxide, treating and exhausting the non-condensing gas, and performing conventional rectification on a
liquid phase part, so as to obtain a low-
boiling point component of which the
boiling point is lower than the
boiling point of
benzoic acid; circulating into the oxidation reactor to continue to
oxide, and performing further conventional rectification on the
tower bottom component, so as to sequentially obtain the
benzoic acid, m-methylbenzoate and p-toluylic acid products. The method has the advantages that the technology is simple, the cost of
raw material is low, the equipment investment is little, the
yield rate is high, the selectivity is good, and the economic benefit is good.