PURPOSE: To provide an improved process for preparation of 1,2-5,6-diacetone-D- glucose.

CONSTITUTION: A process for preparation of 1,2-5,6-diacetone-D-glucose is provided. The process is characterized by reacting α-D-glucose with acetone in the presence of Lewis acid at a temperature of from 80°C to 120°C under a pressure of at least 2.5 bar, distilling off components which are volatile under these conditions to substitute the quantity of the distillate with acetone until 5/3 times of the initial reaction liq. quantity are substituted by the acetone, then, distilling off the reaction mixture under a reduced pressure and at a temperature in the range from 30°C to 70°C, mixing the reaction mixture with an aqueous solution of a base, distilling off the reaction mixture under a reduced pressure and at a temperature in the range from 30°C to 70°C, extracting the reaction mixture with an organic extractant, distilling off the extractant, adding the residue with an organic precipitator, heating the mixture to a temperature in the range from 65°C to 80°C, cooling it and isolating the generated crystals.