Thermal and oxidative decomposition of ibuprofen-based ionic liquids

The objective of this work was to show the decomposition of pharmaceutical ionic liquids (IL-APIs) via thermal and oxidative methods. Long- and short-term thermal decomposition and oxidative processes in the presence and absence of H2O2 and UV-C irradiation were investigated for four IL-APIs derived from ibuprofen. The results of short-term thermal stability experiments showed that the IL-APIs were thermally stable up to 160–200 °C, and have an activation energy of 60–100 kJ mol−1 for decomposition, which indicates that thermal decomposition requires high energy consumption. Under long thermal stability condition they were stable up to 50 °C; however, they were totally decomposed after 24 h at 100 °C. At 20–40 °C they can take days (t1/2 = 18–72 days) to years (t1/2 = 13–35 years) to be decomposed. On the other hand, oxidative decomposition in water with or without H2O2 (4–12 min and 2–5 h, respectively) was faster, resulting in decomposition of the IL-APIs in minutes to hours. The decomposition products from the oxidative process were characterized by mass spectrometry, which indicated that the presence of H2O2 facilitates an alternative, efficient, and faster method for decomposition of IL-APIs.Graphical abstract
Source: Journal of Molecular Liquids - Category: Molecular Biology Source Type: research