Polyether-based ionic liquids from simple mixing of terminal diamines with organic acids to dicationic diammonium carboxylates

Abstract

A new family of dicationic ionic liquids (DIL) have been synthesised by the mixing of either 4,7,10-trioxa-1,13-tridecanediamine or a low molecular weight JeffamineTM with organic acids such as formic acid, acetic acid, propionic acid, butyric acid, maleic acid, valeric, hexanoic acid, heptanoic acid, benzoic acid and octanoic acid. The structure of the DILs was determined by 1H and 13C NMR and LC-MS. All ILs were soluble in protic polar solvents, especially DMSO, and mostly insoluble in aprotic or non-polar solvents. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to assess the thermal properties of the DILs. Temperature-dependant viscosity and ionic conductivity values were measured at temperatures ranging from 25 to 45 °C. The electrochemical stability of the library of ILs was determined using cyclic voltammetry (CV) with a working electrochemical window of 1.2 V (−0.6 V to 0.6 V).