Flammability hazard analysis of imidazolium-based ionic liquid binary mixtures under high temperatures. (March 2020)

• Record Type: Journal Article
• Authors: Li, Yongheng; Pan, Yong; Huang, Gaosheng; Wang, Qingguo; Wei, Qian; Jiang, Juncheng
• Is Part Of: Journal of loss prevention in the process industries. Volume 64(2020)
• Publication Date: 2020-03
• Subjects: Flash point -- Flammability -- Thermal stability -- Imidazolium ionic liquid -- Binary mixtures; Chemical industries -- Safety measures -- Periodicals; 660.2804
• DOI: 10.1016/j.jlp.2020.104081
• Languages: English
• ISSNs: 0950-4230

Abstract

Abstract: Ionic liquid (IL) mixtures are promising because they can optimize the involved properties according to industrial needs. It has already been demonstrated that IL flammability is due mainly to IL decomposition generating flammable substances. Four different ILs, 1-Butylimidazolium tetrafluoroborate ([BIM][BF4 ]), 1-butylimidazolium nitrate ([BIM][NO3 ]), 1-butyl-3-methylimidazolium tetrafluoroborate([BMIM][BF4 ]), and 1-butyl-3-methylimidazolium nitrate ([BMIM][NO3 ]), were selected as the parent salts to form the different imidazolium-based IL binary mixtures. These mixtures were tested via isothermal thermogravimetric analyzer (TGA) at different temperatures (120, 150, 180, 210, and 240 °C), then tested by the flash point analyzer after isothermal heating pretreatment at the above temperatures. Results show that the mixtures' flash point values decrease with the heating temperature increase. Vaporization of the IL mixtures' decomposition products results in a higher concentration of flammable gases and a flash point decrease, which lead to the flammability hazard increasing. Moreover, results show that the flash points of the studied binary imidazolium IL mixtures are more similar to those of the more unstable IL in their parent ILs. Also, the flammability hazard of IL binary mixtures may obviously increase under the high temperature environment for a long time. Highlights: Four IL mixtures were tested by the FP analyzer after isothermal heating at different temperatures. The IL mixtures' flash point values decrease with the heating temperature increase. The IL mixtures' flash point values are more similar to the more unstable IL in their parent ILs. The flammability hazard of IL mixtures may increase under high temperature for a long time. This study would provide guidance for prioritizing design of safer IL mixtures.