Increased flammability hazard when ionic liquid [C₆mim][Cl] is exposed to high temperatures

Area of Science:

• Materials Science
• Chemical Engineering
• Industrial Safety

Background:

• Ionic liquids (ILs) are increasingly used in industrial applications, often involving high temperatures.
• The thermal stability and associated flammability hazards of ILs under operational conditions require thorough investigation.

Purpose of the Study:

• To investigate the thermal decomposition of 1-hexyl-3-methylimidazolium chloride ([C6mim][Cl]) at elevated temperatures.
• To assess the impact of this decomposition on the flammability hazard, specifically the flash point.

Main Methods:

• Thermal decomposition analysis using thermogravimetric analyzer (TGA) and Fourier transform infrared spectroscopy (FTIR).
• Flash point determination using a commercial flash point analyzer.
• Identification of decomposition products using integrated TGA-FTIR and pyrolysis-gas chromatography-mass spectrometry.

Main Results:

• Thermal decomposition of [C6mim][Cl] was observed upon heating, releasing flammable gases like chloromethane and hexene.
• Decomposition products altered the composition of the residual liquid phase.
• Increased mass loss rate and decreased flash point were observed at high temperatures due to vaporization of decomposition products.

Conclusions:

• The chemical decomposition of [C6mim][Cl] at high temperatures significantly increases its flammability hazard.
• Industrial applications of this ionic liquid must consider its thermal decomposition profile to mitigate fire risks.