Chapter 17: Solubility Parameters: A Brief Review
Published:08 Sep 2017
The main objectives of this chapter are to provide a concise overview of the development of the solubility parameter (δ) concept, presentation of the main physico-chemical aspects concerning δ-related models in solution chemistry, a survey of the usefulness of solubility parameters in practically important areas of physical chemistry and chemical engineering, and lastly a brief report of recent theoretical efforts in this field: that is, on equation-of-state approaches, group-contribution methods, and Monte Carlo and molecular dynamics simulation methods for estimating solubility parameters. Prediction of thermodynamic properties of liquid solutions from properties of the pure constituents has come a long way since the classic studies in this field by Scatchard and Hildebrand, leading to regular solution theory in which the solubility parameter is the pivotal property. The effects of temperature and pressure upon δ will be presented, and finally, extensions to multi-dimensional solubility parameters will be indicated, where quantities are intended for application to liquid mixtures containing strongly polar (p) and/or hydrogen-bonded (h) substances. Pride of place will be given to the most widely used three-dimensional solubility parameter introduced by Hansen in 1967: δ2≡δ +δ+δ, where the subscript d indicates dispersion interactions.