METHOD OF OBTAINING CONCENTRATED AQUEOUS SOLUTIONS OF GLYOXALIC ACID Russian patent published in 2019 - IPC C07C59/153 C07C51/41 C07C51/02 

FIELD: chemistry.

SUBSTANCE: way includes the stage of oxidation of an aqueous solution of glyoxal, processing the mixture of products of oxidation of glyoxal spend magnesium oxide to pH 7–8 for the formation of a mixture of soluble magnesium glyoxalate and a slightly soluble precipitate of magnesium oxalate with its subsequent filtration and adding with stirring to the filtrate a solution of calcium chloride at the amount of 0.5–1.0 mol for each mol of oxidized glyoxal, filtering the resulting precipitate and further obtaining the target glyoxalic acid (GK) by adding dropwise to a suspension of calcium glyoxylate in water of HF solution in an amount of 2 mol for each mole of calcium glyoxylate, with the subsequent filtration and concentration of the acid solution under vacuum to obtain 50 % solution.

EFFECT: proposed method for obtaining a concentrated GK solution from glyoxal oxidation products (GO), that is widely used as a reagent for the preparation of drugs (allantoin, atenolol), vanillin, glyphosate.

1 cl, 4 ex