Investigation of the thermal decomposition kinetics of bezafibrate

The thermal decomposition kinetics of bezafibrate in a nitrogen atmosphere has been investigated by analyzer DTG-60. The thermal behavior of bezafibrate at the different heating rates 4, 8, 12, 16 and 20 °C min −1 displays two-stage decomposition processes among 500–650 K. The activation energy ( E ) and pre-exponential factor ( A ) were calculated to be 128.72 kJ mol −1 and 3.56 × 10 10  min −1 by Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, Doyle, Kissinger and Šatava–Šesták methods for the second-stage decomposition process. The results show that the non-isothermal thermal decomposition mechanism of bezafibrate is classified as three-dimensional diffusion model, and the integral and differential equations are \(g(\alpha ) = [1 - (1 - \alpha )^{1/3} ]^{2}\) and \(f(\alpha ) = \frac{3}{2}\left( {1 - \alpha } \right)^{{{\raise0.7ex\hbox{$2$} \!\mathord{\left/ {\vphantom {2 3}}\right.\kern-0pt} \!\lower0.7ex\hbox{$3$}}}} \left[ {1 - \left( {1 - \alpha } \right)^{{{\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 3}}\right.\kern-0pt} \!\lower0.7ex\hbox{$3$}}}} } \right]^{ - 1}{.}\) The enthalpy (Δ H ≠ ), entropy (Δ S ≠ ) and Gibbs free energy (Δ G ≠ ) were calculated to be 123.74 kJ mol −1 , −91.07 J mol −1  K −1 and 178.29 kJ mol −1 , respectively.