Fluid Phase Equilibria, Vol.123, No.1-2, 167-187, 1996
Solid-Liquid Equilibria for Systems Containing Long-Chain 1-Alkanols .2. Experimental-Data for 1-Dodecanol, 1-Tetradecanol, 1-Hexadecanol, 1-Octadecanol or 1-Eicosanol Plus CCl4 or Plus Cyclohexane Mixtures - Characterization in Terms of DISQUAC
Solid-liquid equilibrium (SLE) temperatures for 1-dodecanol, 1-tetradecanol, 1-hexadecanol, 1-octadecanol or 1-eicosanol + CCl4 mixtures and for 1-dodecanol or 1-tetradecanol + cyclohexane systems have been measured by a dynamic method between 273 K to the melting point of the alcohol. First order transitions between different crystal forms (alpha, beta, gamma) of the alcohols were observed, The solid-solid transitions of these long-chain alcohols changed with the solvent as result of solute-solvent interactions. This behaviour is also encountered in many other systems. The hydroxyl/cyclohexane and hydroxyl/CCl4 interactions present in the investigated systems were characterized in terms of DISQUAC, reporting the interchange coefficients for such contacts. It is remarkable that these interchange coefficients remain constant for a given alcohol : from 1-octadecanol for mixtures with cyclohexane, and from 1-hexadecanol for those systems containing CCl4. Calculations were developed taking into account the solid-solid transitions of the 1-alkanols. This is important because of the large value of the molar heat of the alpha --> beta transition. For mixtures containing alcohols other than 1-eicosanol the relative standard deviations for the equilibrium temperatures were less than 0.009. For mixtures containing 1-eicosanol the relative standard deviations were close to 0.020, because the model cannot, using the proposed interaction parameters, reproduce their negative deviations from Raoult’s law.
Keywords:GROUP CONTRIBUTION MODEL;ORGANIC MIXTURES;THERMODYNAMIC PROPERTIES;PHASE-EQUILIBRIA;EXCESS FUNCTIONS;TERNARY-SYSTEMS;BINARY-MIXTURES;PREDICTION;ALKANE;SOLUBILITY