Extended Real Associated Solution Model Research Articles

Response to “Comment on ‘New statistical mechanical model for calculating Kirkwood factors in self-associating liquid systems and its application to alkanol+cyclohexane mixtures’ ” [J. Chem. Phys. 127, 047101 (2008)

A short summary of our theoretical concept for predicting Kirkwood factors in associating liquids system is presented which is based on the so-called extended real associated solution model involving the dipole correlations of chainlike associated alcohol molecules including a cyclic tetramer. Our model is discussed by comparing it with a different, alternative approach developed by Durov et al. Critical agreements and incorrect statements made by Durov have been discussed and tried to clarify.

Excess volumes and isobaric heat capacities of diisopropyl ether with several alkanols at 298.15 K : Application of the symmetrical extended real associated solution model

Excess molar volumes v E and isobaric heat capacities C p E at 298.15 K were measured for 11 mixtures of diisopropyl ether (DIPE)+alcohol (from methanol to 1-undecanol), DIPE with n-heptane and 2,4-dimethylpentane with 1-octanol. Moreover the excess molar enthalpy h E of DIPE with n-heptane at the same temperature was also measured in order to obtain the self-association parameters of the symmetrical extended real associated solution (SERAS) model for DIPE. Parameters of the SERAS model corresponding to the interaction of DIPE with each alcohol were obtained by fitting v E data reported here and h E data taken from a previous work. The results obtained are compared with those from the literature obtained by using the ERAS model in the traditional way for several of the studied mixtures. C p E curves are qualitatively explained in terms of the SERAS model.

Prediction of the speed of sound in the ethanol+ n-heptane system : New application of the Extended Real Associated Solution model

The ERAS (Extended Real Associated Solution) Model developed by Heintz [A. Heintz, Ber. Bunsenges. Phys. Chem., 89 (1985) 172] for describing thermodynamic excess properties of alcohol+alkane mixtures, was modified, in order to take into account the effect of pressure ( p≠0), and applied for calculating the compressibility and the speed of sound in ethanol+n-heptane mixtures at T=298.15 K and p=0.1 MPa. The calculated compressibility and ultrasonic speed values are in good qualitative agreement with the experimental ones. Even the quantitative consistence seems to be rather satisfactory (the differences between the calculated and experimental speed values do not exceed 0.5% in the whole concentration range).

Application of the extended real associated solution model to predict thermodynamic properties of n-alcohol + linear monoether mixtures

Applicability of the extended real associated solution (ERAS) model to describe and predict properties of n-alcohol + unbranched monoether mixtures has been tested. Two versions of the model have been applied: its original, developed by Heintz [1] and a modified form, reported recently by Hofman and Casanova [2]. The basic assumption states that the purely physical contribution to the model should be meaningless. The model has three adjustable parameters which are common for all the mixtures considered. It has been applied to predict H E, V E and VLE data. The modified version gives acceptable results which for the non-volume properties are similar to those predicted by the Modified UNIFAC (Dortmund) using six parameters. The original ERAS model turned out to be inadequate.