Betulonic acid.

Even if up to date, betulonic acid (BA) was not investigated for biological activities as much as other triterpenic derivatives like betulinic acid, and there are several papers describing the synthesis, isolation and investigations-both instrumental and biological-of this compound. In this paper, the kinetic behavior associated with thermal decomposition of BA in oxidative conditions is presented. The kinetic study was realized on the main decomposition process which occurs in the 200-300 °C temperature range, according to the ICTAC 2000 protocol, namely employing three isoconversional methods, one differential (Friedman) and two integral (Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa). In order to separate the multistep contributions to the degradation process of BA, the NPK method was employed. This method suggested that the degradation occurs by two parallel processes, with different energetic contributions, with a mean value of 162.1 ± 5.5 kJ mol. [ABSTRACT FROM AUTHOR]