Comparative study on the thermal behavior of two similar triterpenes from birch

A comparative study on the thermal behavior of betuline and betulinic acid was performed using a TG-FTIR hyphenated technique. The comparison was focused on the kinetic of the relevant thermal-induced phenomenon. Using three different data processing strategy, that is, Friedman, Flynn-Wall-Ozawa, and nonparametric kinetic, homogeneous values for the activation energy were obtained, especially by betulinic acid. The advantages of the nonparametric kinetic method were revealed, especially by obtaining the explicit kinetic parameters of the conversion function, without any a priori hypothesis.