Method of Preparation and Isolation of Betulin Diacetate from Birch Bark from Paper Mills and its Optional Processing to Betulin
Abstract
The invention relates to a method of preparation and isolation of betulin diacetate from birch bark from paper mills and its optional processing to betulin, wherein the birch bark is ground, mixed with two- to twenty-fold excess volume of water and is stirred so that all birch bark is dipped, then the fraction of the birch bark which floats on the surface is collected, said collected fraction is dried at the temperature in the range of from 50 to 85 DEG C. and betulin contained is then subjected to an acetylation reaction, after the acetylation the birch bark is dried at the temperature of from 50 to 100 DEG C. and the formed betulin diacetate is then isolated from the birch bark by SE of the birch bark with carbon dioxide at 28-35 MPa and the temperature of from 50 to 100 DEG C. and subsequently, the supercritical extract is recrystallized for direct use or for further processing. The further processing can be basic hydrolysis of the re-crystallized betulin diacetate to betulin.