Multi-path method based on dynamic and isothermal techniques to evaluate the thermal stability and hazard of 1-butyl-3-methylimidazolium dicyanamide

• Published in: Journal of thermal analysis and calorimetry 2023-06, Vol.148 (11), p.4897-4904
• Main Authors: Wang, Wen-Tao, Liu, Shang-Hao, Su, ChungHwei, Cheng, Yang-Fan
• Format: Article
• Language: English
• Subjects: Analysis; Analytical Chemistry; Chemistry; Chemistry and Materials Science; Dynamic stability; Fourier transforms; Hazard assessment; Heating rate; High temperature; Industrial safety; Infrared analysis; Infrared spectroscopy; Inorganic Chemistry; Ionic liquids; Measurement Science and Instrumentation; Methods; Physical Chemistry; Polymer Sciences; Pyrolysis; Stability analysis; Thermal stability; Thermogravimetric analysis
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-022-11726-5

The ionic liquid 1-butyl-3-methylimidazolium dicyanamide ([Bmim][Dca]) is a novel solvent suitable for a wide range of applications in the petrochemical industry. However, the thermal safety of [Bmim][Dca] IL has not been fully considered when developing new uses, especially in areas involving high-temperature work. Starting from the initial decomposition temperature of [Bmim][Dca] IL, this article tries to find the highest temperature suitable for its intrinsic safety and provides a basis for its industrial production. The thermal stability of [Bmim][Dca] IL and its pyrolysis gas detection were obtained by simultaneous thermogravimetric analyser (STA) and thermogravimetric analysis coupled with Fourier infrared spectroscopy (TG-FTIR), respectively. Furthermore, the constant temperature experiments by STA show that the mass loss of [Bmim][Dca] IL at a specific temperature for 10 h is approximately 2% at 160 °C, about 15% at 190 °C, and more than 30% at 210 °C. The mass loss in the dynamic heating experiment is divided into two steps at each heating rate. The pyrolysis gas detection experiments by TG-FTIR show that extremely toxic gas such as HCN will be produced at 154 °C ( T 0.01/10 h ). The real-time photography system by STA observed significant colour changes in samples at this temperature. Therefore, extrapolated temperature ( T MOT,10 h,e ) was defined to obtain a more accurate maximum operation temperature. Comparative experimental results show that the T MOT,10 h,e obtained by the extrapolation method has high reliability. The results of this study would provide a relevant basis for safer control based on the thermal hazard assessment of [Bmim][Dca] IL.