Evaporation and thermal decomposition of 1-ethyl-3-methylimidazolium chloride

The use of ionic liquids (IL) at elevated temperatures has revealed interest in the study of evaporation and thermal decomposition (thermolysis) processes that determine the thermal stability of IL. In this work the evaporation of 1-ethyl-3-methyl-imidazolium chloride ([EtMIm][Cl]), which is accompanied by the significant thermal decomposition, was studied by the Knudsen cell mass spectrometry. The composition of gas phase over [EtMIm][Cl] and its change in time were established in the temperature range of 403- 449 K. The saturated vapor pressures, vaporization enthalpy and rate constants of thermolysis reactions were determined. The equilibrium and rate constants for gas-phase thermolysis reactions of [EtMIm][Cl] were calculated by the quantum chemical methods. Based on the results of experiments and calculations, the processes responsible for mass loss - thermolysis and evaporation - were quantitatively described. (c) 2023 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the evaporation and thermal decomposition process of 1-ethyl-3-methyl-imidazolium chloride at elevated temperatures. The gas phase composition and its change over time were determined, along with the saturated vapor pressures, vaporization enthalpy, and rate constants of thermolysis reactions. The equilibrium and rate constants for gas-phase thermolysis reactions were calculated using quantum chemical methods, providing a quantitative description of the processes responsible for mass loss.