EXTRACTION OF BETULIN BY VACUUM PYROLYSIS OF BIRCH BARK

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.

Keywords:

• Betulin
• Birch
• Bark
• Extraction
• Sublimation
• Vacuum
• Pyrolysis
• Analysis

Acknowledgments