A correlation that is suitable for predicting infinite dilution binary activity coefficients of saturated, unsaturated and aromatic hydrocarbons from the pure physical constants of their components is presented.
The original equation was obtained by Weimer and Prausnitz by using the Scatchard-Hildebrand and Flory-Huggins activity equation. The equation was then revised by Helpinstill-Winkle and the present study improved it further by introducing the concept of Wilson's local volume fraction.
Data from over 180 binary hydrocarbon solvent systems were used to improve the correlation. The calculated infinite dilution activity coefficients were compared with those predicted by Helpinstill-Winkle. It has been proved that the new expression was more satisfactory in prodicting the infinite dilution activity coefficients.