The invention provides an Alpha-ketobutyric acid preparation method which comprises the following steps: A), taking
dimethyl oxalate or
diethyl oxalate as raw materials to solve in
anhydrous furanidine, cooling, adding ethylmagnesium
bromide solution, stirring, removing
solvent through
distillation under reduced pressure after reaction termination, allowing residual mixture to be subjected to rectification under reduced pressure, and collecting
intermediate product 2-oxo
methyl butyrate or 2-oxo
ethyl butyrate; B), solving the
intermediate product in a
hydrochloric acid, heating, reflowing, stirring, performing extraction by vinegar
naphtha after the completion of the reaction, collecting organic phase,
drying, filtering, and removing the
solvent through allowing the filtrate to be subjected to
distillation under reduced pressure, so as to obtain a coarse product Alpha-ketobutyric acid; and c), allowing the coarse product Alpha-ketobutyric acid to be subjected to rectification under the reduced pressure, and collecting the Alpha-ketobutyric acid. The method provided by the invention has the advantages of inexpensive and easy-to-get raw materials, lower
toxicity, simple preparation process, easiness in control, no complex purification process, high product purity,
high productivity, and greatly reduced manufacturing cost, and is suitable for large scale industrialized application.