The effect of structural modifications on the thermal stability, melting points and ion interactions for a series of tetraaryl-phosphonium- based mesothermal ionic liquids

CA Cassity and B Siu and M Soltani and JL McGeehee and KJ Strickland and M Vo and EA Salter and AC Stenson and A Wierzbicki and KN West and BD Rabideau and JH Davis, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 19, 31560-31571 (2017).

DOI: 10.1039/c7cp06278h

A family of mesothermal ionic liquids comprised of tetraarylphosphonium cations and the bis(trifluoromethanesulfonyl) amidate anion are shown to be materials of exceptional thermal stability, enduring (without decomposition) heating in air at 300 degrees C for three months. It is further established that three specific structural elements - phenoxy, phenacyl, and phenyl sulfonyl - can be present in the cation structures without compromising their thermal stability, and that their incorporation has specific impacts on the melting points of the salts. Most importantly, it is shown that the ability of such a structural component to lower a salt melting point is tied to its ability to lower cation-cation repulsions in the material.

Return to Publications page