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ABSTRACT
Separation of betulin from the outer bark of Betula papyrifera birch tree by sublimation in a batch vacuum pyrolysis reactor was studied in the temperature range of 250–300°C and under a total pressure of 0.7 kPa. Yield of 9.5% by weight of betulin on an anhydrous bark basis was obtained. The total yield of extractives was in the range of 28–32%. The purification of betulin was achieved by solvent extraction followed by crystallization. In comparison, soxhlet extraction using dichloromethane yielded 11.5% of betulin. The structural analysis of the purified betulin has been made by GC/MS and 1H NMR.