Insight into degradation of ammonium-based ionic liquids and comparison of tribological performance between selected intact and altered ionic liquid

Due to lack of experimental work clearly describing ionic liquids (ILs) degradation which could take place under application conditions, specially designed artificial alteration experiments were performed to derive degradation mechanisms most probably taking place under long-term thermo-oxidative stress. The use of mass spectrometry enabled identification of IL degradation products both in liquid and gas phases. The mechanisms of intermolecular transmethylation in ammonium ILs proceeding via anion-derived intermediates have been identified. Hence, care has to be taken for applying ILs in processes, e.g. in lubrication applications, as it is shown that IL altered products can negatively influence friction and wear performance as well as can lead to build-up of vapour pressure in otherwise non-volatile ILs.