VISCOSITY PREDICTION FROM A MODIFIED SQUARE-WELL INTERMOLECULAR POTENTIAL MODEL

A statistical mechanical based model for simultaneously calculating li quid and gas phase viscosities using the square well intermolecular po tential has been developed. Theoretical results are utilized along wit h modifications to correct the model for the molecular chaos assumptio n and the inadequacy of the square well potential. The radial distribu tion function values are determined from perturbation theory. Model pa rameters are obtained from liquid and gas viscosity data and generaliz ed with group contributions. With the resulting model, liquid and gas viscosities of a variety of nonpolar compounds are correlated within 5 % and 3%, respectively, and predicted within 8% and 5%, respectively.