The study of decomposition of 1-ethyl-3-methyl-imidazolium bis (trifluoromethylsulfonyl)imide by using Termogravimetry: Dissecting vaporization and decomposition of ILs

The question of thermal stability of ionic liquids (Rs) is often raised in the scope of industrial application of ILs. The most widely used approach for this purpose is Thermo Gravimetric Analysis (TGA) with the determination of decomposition "T-onset" incorrectly called Decomposition Temperature. In the present study with the help of TGA study of 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide we have shown the T-onse(t) or specified mass-loss rate cannot be applied as the innitial point of decomposition. We have proposed a new approach allowing dissecting the mass loss caused by vaporization of the sample and its thermal decomposition. The further analysis of the decomposition mass loss by using "isoconversional kinetics" allows to determine kinetic parameters of decomposition such as pre-exponential factor A and activation energy E-A. The experimental activation energy E-A = (250 +/- 15) kJ.mol(-1) agreed with the gas phase B3LYP calculated value by Kroon E-A = 250 kJ.mol(-1). (C) 2020 Elsevier B.V. All rights reserved.