Analysis of dipolarity/polarisability parameter, pi*, for a range of supercritical fluids

The dipolarity/polarisability parameter, pi*, of Kamlet and Taft can be use d to characterise the solvent properties of supercritical fluids and hence its correlation to more readily available parameters is important for predi ctive purposes. Almost perfect correlations are demonstrated between the pi * parameter and the cohesive energy density parameter, delta (2)(H), as a f unction of solvent type, temperature and pressure. Correlation is also obse rved between pi* and solvent dipole moment at constant reduced density. It is shown that the Gibbs energy of dissociation data can be modelled using d elta (2)(H) and pi* parameters.