METHOD OF BETULIN PREPARING Russian patent published in 2002 - IPC

FIELD: wood processing. SUBSTANCE: method involves birch bark milling, its separation for birch bark and bast fiber, extraction of birch bark, separation of solution followed by solvent removal from solution. Birch bark extraction is carried out with toluene at temperature 90-110 C for 1.5-3.0 h and solution is filtered at temperature 40-50 C. Toluene betulin solution is cooled for 6-10 h to temperature (+15) - (+5) C. Precipitated betulin crystals are mixed with mother liquid, filtered, washed out with pure toluene, filtered and dried. Crystals are washed out with ethyl alcohol or isopropyl alcohol followed by washing out with water and dried. EFFECT: improved method of preparing, increased yield, enhanced quality of product.