A study of the molecular interactions between ammonium-based ionic liquids and N,N-dimethylacetamide

Abstract

In this work, we report the molecular interactions of different cation alkyl chain lengths with same anion of ammonium-based ionic liquids (ILs) such as tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH) and tetrabutylammonium hydroxide (TBAH) with N,N-dimethylacetamide (DMA) through thermophysical properties with varying the compositions of ILs at different temperatures from 25 to 40 °C under atmospheric pressure. Experimental densities (ρ), ultrasonic sound velocities (u), viscosities (η) and refractive indices (nD) of binary mixtures of ILs with DMA are measured over the wide composition range. The excess molar volumes (VE), deviation in isentropic compressibilities (Δκs), deviation in viscosities (Δη) and deviation in refractive indices (ΔnD) are calculated from experimental values and are correlated by Redlich-Kister polynomial equations. Consequently, VE values show that negative for small cation alkyl chain length of ammonium-based ILs as compared to large cation alkyl chain length of ILs. We have observed the strength of intermolecular interactions such as hydrogen bonding, ion-ion pair interactions and induced dipole interactions between the ions of ammonium-based ILs with DMA from obtained data. Thermophysical properties, however, possessed by these binary systems are exceedingly promising and predictable that these systems will find applications in chemical industry.