Density and Excess Molar Volume for Binary Mixtures of Naphthenic Acid Ionic Liquids and Ethanol

Abstract

The design and synthesis of biodegradable ionic liquids has been one of the ways to accelerate the pace of ionic liquid large-scale industrial applications and prevent environmental hazards. The knowledge of thermodynamic properties for the mixtures of biodegradable ionic liquids with organic solvent or water has been paramount for the design of many technological processes. In this work, the densities of two binary systems for biodegradable naphthenic acid ionic liquids, choline cyclohexane carboxylate ([Ch][CHC]), and choline cyclopentane carboxylate ([Ch][CPC]) with ethanol were measured over the whole range of compositions from (293.15 to 323.15) K. The excess molar volumes of two systems were obtained from experimental data and fitted to the Redlich−Kister equation. The results showed that VE values were negative over the entire composition range, and its absolute values increased slightly with increasing temperature from (293.15 to 323.15) K. A minimum value of the two systems was located at 0.3 and 0.4, respectively. Estimated coefficients and standard error value were also presented.