Besides the UNIFAC model, there are still some other prediction models used for predicting activity coefficients at infinite dilution whenever experimental data are unavailable, e.g. MOSCED model, SPACE model and COSMO-RS model.
The MOSCED (modified separation of cohesive energy density) model is an extension of regular solution theory to mixtures that contain polar and hydrogen-bonding components [43-47], The cohesive energy density is separated into dispersion forces, dipole forces and hydrogen bonding, with small corrections made for asymmetry. The dipolarity and hydrogen bond basicity and acidity parameters are correlated on the basis of a limited database of activity coefficients. By using the expression for the cohesive energy density and accounting for the asymmetry effect, the activity coefficient at infinite dilution for component 2 in solvent 1 is written as
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