Study on thermodynamic properties for binary systems of water + L-cysteine hydrochloride monohydrate, glycerol, and D-sorbitol at various temperatures

Abstract

Viscosities, refractive indices, and densities for aqueous solution of L-cysteine hydrochloride monohydrate ([LCHCMH]) and D-sorbitol, and also densities (ρ), refractive indices (n D), excess molar volumes (V E), and change of refractive indices on mixing (Δ n D) for aqueous solution of glycerol have been measured at several mole fractions and temperatures (between T = 303.15 K and T = 323.15 K) at atmospheric pressure. The measurements were carried out using a vibrating-tube density meter for density, an Abbe refractometer for refractive index, and an Ubbelohde viscometer for viscosity. From these data for aqueous solution of glycerol, the excess molar volumes and the change of refractive indices on mixing were calculated and fitted to the Redlich-Kister polynomial equation. Also for aqueous solutions of [LCHCMH], glycerol, and D-sorbitol, the density and refractive indices were fitted with the experimental equations to estimate the adjustable parameters and relative deviations. It has been observed for aqueous solution of glycerol that the excess molar volumes and change of refractive indices on mixing increase and decrease with increasing temperature, respectively. © 2013 F. Koohyar et al.