Influence of oxidizing gas atmosphere on thermal stability and safety risk of 1-buty-3-methylimidazolium tetrafluoroborate

• Published in: Journal of thermal analysis and calorimetry Vol. 148; no. 11; pp. 4717 - 4727
• Main Authors: Xia, Rui, Liu, Shang-Hao, Wang, Wen-Tao, Chu, Feng-Jen
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.06.2023; Springer; Springer Nature B.V
• Subjects: Adiabatic flow; Analytical Chemistry; Atmospheres; Calorimetry; Chemistry; Chemistry and Materials Science; Combustion; Decomposition; Decomposition (Chemistry); Decomposition reactions; Fourier transforms; Hazards; Infrared spectroscopy; Inorganic Chemistry; Liquid fuels; Measurement Science and Instrumentation; Nitrogen; Oxidation; Physical Chemistry; Polymer Sciences; Safety; Safety and security measures; Temperature effects; Thermal stability; 1-Butyl-3-methylimidazolium tetrafluoroborate; Decomposition mechanism; Thermal stability; Adiabatic runaway
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-022-11755-0

1-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF 4 ) is often used as an extractive desulfurization of liquid fuels. However, the role of air and nitrogen atmospheres on thermal effect of [Bmim]BF 4 has been shown to the opposite. Thus, the effect of oxidizing gases on thermal stability and safety risk of [Bmim]BF 4 is worth further investigation. In this study, the thermal stability, decomposition mechanism, and thermal hazards of [Bmim]BF 4 were studied by thermogravimetric (TG), simultaneous application of thermogravimetric with a Fourier transform infrared spectroscopy (TG-FTIR), and accelerated adiabatic calorimetry (ARC). Obtained by thermogravimetric experiments, the long-term thermal stability of [Bmim]BF 4 is MOT 8000 = 92 ℃ under air and MOT 8000 = 112 ℃ under nitrogen. TG-FTIR shows that the decomposition mechanism is different in the two atmospheres; CO 2 is only produced under air, indicating that the decomposition products of [Bmim]BF 4 undergo combustion and release huge heat, which explains the exotherm of DSC images in air. In adiabatic experiments, different atmospheres affect the decomposition reaction order of [Bmim]BF 4 . Nitrogen suppresses the thermal effect of [Bmim]BF 4 , because although the decomposition rate of [Bmim]BF 4 before runaway is much greater under nitrogen than under air, the maximum temperature and maximum pressure are still less than under air. The thermal stability, thermal effect, and adiabatic runaway of [Bmim]BF 4 in different atmosphere are a typical representations of ILs, which proves that oxidizing atmosphere has a great negative influence on thermal hazards of [Bmim]BF 4 .