Long-term thermal stability of fatty acid anion-based ionic liquids

Authors: Ramajo, B., Blanco, D., Rivera, N., Viesca, J.L., González, R., Battez, A.H.

Journal: Journal of Molecular Liquids

Publication Date: 15/04/2021

Volume: 328

ISSN: 0167-7322

DOI: 10.1016/j.molliq.2021.115492

Abstract:

Isothermal and dynamic methodologies were used to study the thermal degradation of 8 novel fatty acid anion-based ionic liquids (FAILs): methyltrioctylammonium hexanoate [N8,8,8,1][C6:0], methyltrioctylammonium octanoate [N8,8,8,1][C8:0], tetrahexylammonium octanoate [N6,6,6,6][C8:0], methyltrioctylammonium laurate [N8,8,8,1][C12:0], methyltrioctylammonium palmitate [N8,8,8,1][C16:0], tetrahexylammonium palmitate [N6,6,6,6][C16:0], methyltrioctylammonium stearate [N8,8,8,1][C18:0] and methyltrioctylammonium oleate [N8,8,8,1][C18:1]. The thermal stability of these FAILs is controlled by both the cation and anion and most samples have an onset decomposition temperature (Tonset) below 200 °C. All the FAILs exhibited lower thermal stability under a nitrogen atmosphere than commercially available ILs tested previously in lubrication studies, particularly when compared to those containing the [NTf2]⁻ anion. The [N8,8,8,1][C6:0] and [N8,8,8,1][C8:0] showed the highest long-term thermal stability, probably related to their stronger anion-cation electrostatic interaction. This led to a multi-step thermal decomposition mechanism observed in the DTG results. Finally, isoconversional modelling for the [N8,8,8,1][C12:0] agrees with isothermal results.

https://eprints.bournemouth.ac.uk/35524/

Source: Scopus