Densities, viscosities, and refractive indexes of Good's buffer ionic liquids

Abstract

Good’s buffer ionic liquids (GB-ILs) have demonstrated their potential usefulness in the biotechnological field due to their advantageous properties of self-buffering and biocompatibility. To further investigate the applicability of these solvents in industrial process, the knowledge of the thermophysical properties of such solvents is of utmost importance. In this work, a series of GB-ILs prepared by the combination of the Good’s buffer anions MOPSO, BES, TAPSO, and CAPSO, with tetrabutylammonium, tetrabutylphosphonium, and cholinium cations were synthesized and characterized regarding the determination of the melting and decomposition temperatures. Additionally, the physical properties such as density, viscosity and refractive index were measured for these GB-ILs at atmospheric pressure and in the (288.15 to 353.15) K temperature range. Additional properties such as the isobaric thermal expansion coefficient and activation energy for viscous flow were also further derived from the temperature dependence of the measured properties. The effects of cation and anion species of GB-ILs on these thermophysical properties are discussed.