Key words: birch tree barks, CO2-extract, biologically active substances, betulin, thermodynamic characteristics, physico-chemical properties
Supercritical fluid extraction with carbon dioxide is used to extract biologically active
substances from the bark of the birch tree (Betula pendula). Phase and relaxation
transitions (melting, crystallization, evaporation, vitrification) in these samples are
studied using differential thermal analysis between 80 and 550 K. Betulin was isolated
and purified from CO2-extracts of birch bark. Its heat capacity in the temperature
range of 80—350 K, as well as temperatures of phase and relaxation transitions and
thermochemical characteristics (standard enthalpy of combustion and formation)
are measured.
doi:10.1134/S1990793114080181