Analysis of the thermal hazards of 1-butyl-3-methylimidazolium chloride mixtures with cellulose and various metals

Abstract

Ionic liquids (ILs) are a relatively new class of environmentally benign and comparatively safe solvents and are expected to have numerous applications in chemical processes. Although pure ILs are thermally stable, the presence of impurities can affect their thermal stability and decomposition behavior. In addition, ILs decomposition products include flammable gases that may present a fire hazard. When designing safer processes and operating conditions, it is therefore important to investigate IL thermal properties and decomposition products in combination with additives. The present work focused on cellulose dissolution which is promising application of ILs to obtain better understanding of thermal hazards. Mixtures of cellulose, iron (III) oxide (Fe2O3), copper(II) oxide (CuO), chromium, and nickel with 1-butyl-3-methylimidazolium chloride (BmimCl) were examined, using differential scanning calorimetry, high-sensitivity calorimetry, and thermogravimetry–differential thermal analysis–mass spectrometry. The addition of CuO was found to generate an exothermic reaction below the decomposition temperature of BmimCl and also to lower the decomposition temperature. BmimCl/CuO mixtures also produced extremely flammable gases below the decomposition temperature of pure BmimCl.