Related Experiment Video
Updated: Aug 11, 2026

Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Thermodynamic modeling of activity coefficient and prediction of solubility: Part 2. Semipredictive or semiempirical
Mahmoud Mirmehrabi1, Sohrab Rohani, Luisa Perry
1Department of Chemical and Biochemical Engineering, The University of Western Ontario, London, Ontario N6A 5B9, Canada.
Abstract:
The solubility of stearic acid, ranitidine hydrochloride, and stavudine were predicted in selected organic solvents. The experimental solubility data of stearic acid and ranitidine hydrochloride were reported in previous work of the authors and stavudine's solubility was measured in this work. Equilibrium aqueous solubility of crystalline stauvudine was determined at controlled temperatures by stirring and filtration, with spectrophotometric quantification. The new model developed in Part 11 of this communication was modified as a semipredictive model with two adjustable parameters. Predicting the solubility data with the NRTL model using just one experimental point resulted in a big error while the modified new model and the UNIQUAC model showed much smaller errors. A new method was proposed in this work for predicting the solubility data of all polymorphs of a given compound using the experimental solubility data of one of the polymorphs of the same chemical compound. Although in general, the UNIQUAC model predictions were marginally superior, the new model is simpler and does not require the molecular parameters such as Van der Waals area and volume. The solubility prediction in a mixture of solvents using the NRTL and UNIQUAC models was also discussed.
More Related Videos
Related Concept Videos
Thermodynamics: Activity Coefficient
The activity coefficient is a measure of the deviation from ideal behavior. When the ionic strength of the solution is minimal, the activity coefficient of an ionic species is close to unity, making...
The Debye–Hückel Theory of Electrolyte Solutions
Solubility Equilibria
The...
Factors Affecting Activity Coefficient
The activity coefficient value for an ion is close to one when the solution has almost zero ionic strength, i.e., when the solution shows close to ideal behavior. As the ionic strength of the solution increases from 0 to 0.1 mol/L, a decrease in the...
Solubility
A solution is a homogeneous mixture composed of a solvent, the major component, and a solute, the minor component. The physical state of a solution—solid, liquid, or gas—is typically the same as that of the solvent. Solute concentrations are often described with qualitative terms such as dilute (of relatively low concentration) and concentrated (of relatively high concentration).
In a solution, the solute particles (molecules, atoms, and/or ions)...
Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model

