PREPARATION OF PYRUVIC ACID ESTER

PROBLEM TO BE SOLVED: To provide a method for producing a pyruvic acid ester by which the pyruvic acid ester is industrially produced without using a catalyst such as bromine and further without requiring a high grade drainage treatment by oxidizing a lactic acid ester with chlorine under irradiation of light in an organic solvent. SOLUTION: A lactic acid ester of 1 pt.wt. in an aromatic compound-based or halogenated aliphatic hydrocarbon-based organic solvent, preferably benzonitrile, monochlorobenzene or dichlorobenzene, of 5-50 pts.wt. is oxidized by chlorine gas of 1.2-1.7 mol equivalent based on the lactic acid ester under irradiation of light such as the light of a halogen lamp to provide the objective pyruvic acid ester in the method for producing the pyruvic acid ester.