Further insights into the kinetics of thermal decomposition during continuous cooling.

Following the previous work (Phys. Chem. Chem. Phys., 2016, 18, 32021), this study continues to investigate the intriguing phenomenon of thermal decomposition during continuous cooling. The phenomenon can be detected and its kinetics can be measured by means of thermogravimetric analysis (TGA). The kinetics of the thermal decomposition of ammonium nitrate (NH4 NO3 ), nickel oxalate (NiC2 O4 ), and lithium sulfate monohydrate (Li2 SO4 ·H2 O) have been measured upon heating and cooling and analyzed by means of the isoconversional methodology. The results have confirmed the hypothesis that the respective kinetics should be similar for single-step processes (NH4 NO3 decomposition) but different for multi-step ones (NiC2 O4 decomposition and Li2 SO4 ·H2 O dehydration). It has been discovered that the differences in the kinetics can be either quantitative or qualitative. Physical insights into the nature of the differences have been proposed.