Isoconversional kinetic analysis of thermal decomposition of 1-butyl-3-methylimidazolium hexafluorophosphate under inert nitrogen and oxidative air atmospheres

Thermal Stability of Ionic Liquids: Current Status and Prospects for Future Development

“…As shown in Figure 10, in order to better characterize the thermal decomposition process of [C4MIM][PF6] in the nitrogen atmosphere, the thermal decomposition is divided into two steps. The activation energy value calculated by the Friedman method suggests that the linearity of the result is relatively poor in the fitting process and the activation energy varies significantly with [55]. In addition, a similar conclusion has also been drawn in other investigations [90].…”

“…The effect of air on thermal stability is similar to that of O2. As shown in Figure 6, [81], and the same results are observed in another study [55]. However, according to Figure 7, the Tonset of some choline, piperidine, and phosphonium ILs are not significantly affected by gas atmospheres, and the maximum temperature difference is only 26 °C [40,73].…”

“…For a series of different heating rates, the activation energy values can be obtained by minimizing the following function: (17) where the subscript denotes different heating programs, and the subscript is used to denote all heating rates other than . In order to reduce error as much as possible, the temperature integral is calculated over a small segment [87] as Table 3 shows that the activation energy values calculated by the Vyazovkin method are similar to the results of the KAS and Starink methods, indicating that the latter two simple integration methods are precise enough in most cases [55,57], and the Vyazovkin method is a better choice when the activation energy values vary with obviously [88]. [91].…”

“…Therefore, the temperature at which the sample begins to decompose is lower than Tonset. Tz (decomposition degree z) is also a parameter to characterize the short-term thermal stability, which directly shows the temperatures at different decomposition degrees [55,63,[67][68][69]. Both parameters are illustrated clearly in Figure 1.…”

“…Arrhenius methods are widely used in kinetics analysis due to their simple calculation process. However, some recent studies have used the isoconversional methods to calculate the activation energy [44,53,54], while the methods of compensation effect and master plots provide the pre-exponential factor calculation [55][56][57].…”