Ionic liquids (ILs) have been embraced as the green solvent of the future and are noted for their operational safety in part due to their non-flammable nature as compared to conventional solvents. In fact, existing regulations for measuring the flammability of solvents do not take into account the particular nature of ILs, with specifications about flash points which do not really apply.
Scientists from France and the US say that, in this context, a material rated as “non-flammable” is not necessarily non-combustible, and so they set out to analyse the true combustion potential of a series of ILs using oxygen bomb calorimetry, pyrolysis flow calorimetry and fire calorimetry. The resulting data show that although difficult to ignite, ILs can release a lot of heat once they start to burn and can also have some pretty nasty degradation products. Many do self-extinguish though. The information could be used to better prepare for the event of an accidental fire involving large amounts of ILs in an industrial context.