METHOD FOR PRODUCING QUERCETIN Russian patent published in 2012 - IPC C07D311/30 D21C3/06 

FIELD: chemistry.

SUBSTANCE: method involves treatment of larchwood with a dihydroquercetin extraction agent, separation of the extract from the solid phase, oxidation of dihhydroquercetin to quercetin in a solution of bisulphite of an alkali, alkali-earth metal or ammonia at temperature 125-145°C, where the extraction agent used is water, treatment is carried out while simultaneously crushing the wood in a disc mill at temperature 20-60°C to obtain a dispersion consisting of a fibrous mass and an extract with dissolved dihydroquercetin. Bisulphite of an alkali, alkali-earth metal or ammonia is added to the separated extract until achieving concentration of the solution of 2% in terms of SO₂ and pH 4.0-6.0. The obtained solution is heated and held for 60 minutes until complete oxidation of dihydroquercetin to quercetin, followed by cooling and extraction of the end product. The bisulphite solution, after extraction of quercetin, and the fibrous mass, after separating the quercetin extract, can be used to produce cellulose fibre.

EFFECT: novel efficient method of producing quercetin, which enables to use larchwood processing by-products to produce cellullose.

2 cl, 1 ex, 1 tbl