Solid-liquid equilibria for systems containing long-chain 1-alkanols III. Experimental data for 1-tetradecanol, 1-hexadecanol, 1-octadecanol or 1-icosanol + 1-butanol, 1-hexanol, 1-octanol or 1-decanol mixtures. Characterization in terms of DISQUAC

Abstract

Solid-liquid equilibrium temperatures for 1-tetradecanol, 1-hexadecanol, 1-octadecanol or 1-icosanol + 1-butanol, 1-hexanol, 1-octanol or 1-decanol systems have been measured by a dynamic method from 275 K to the melting point of the long-chain 1-alkanol. An eutectic point was encountered for those mixtures containing 1-decanol. However, first-order transitions between different crystal forms (α, β, γ) of the long-chain 1-alkanols were observed. It was noted that these solid-solid transitions are very stable in alcohols unlike in hydrocarbons or other solvents. The solubility of a given long-chain 1-alkanol is nearly the same in all alcohols tested from 1-butanol to 1-decanol. Only below the second phase transition point does the solubility change, increasing with the molecular weight of the shorter alcohol. The hydroxyl/hydroxyl interactions present in the investigated systems were characterized in terms of DISQUAC using dispersive interchange coefficients for such contacts. Calculations were developed taking into account the solid-solid transitions of the 1-alkanols. The mean relative standard deviations for the equilibrium temperatures are 0.006 for mixtures with an alcohol in the absence of 1-icosanol; and the experimental data are fairly well represented by ideal solubility curves. For mixtures including 1-icosanol, the mean relative standard deviations are 0.021, as the model cannot reproduce, using the proposed interaction parameters, their negative deviations from Raoult's law.