Antoine type equation for liquid viscosity correlations

A modified Andrade4 equation, similar to the Antoine equation for vapor pressure-temperature correlations, was developed for liquid viscosity-temperature correlations. Included in the investigation were the following compounds: n-alkanes (C2-C20), n-alkenes (C2-C20), n-alkyl benzenes (C6-C10), n-alkyl cyclohexanes (C6-C22), and fifteen polar compounds. Except for propene, errors of less than 5% were obtained. Normal heptadecane was used to compare correlations developed by Andrade4, Walther20, and Doolittle9, with the modified Andrade equation. The latter was found to give the best correlations in fitting the data from the boiling point to the freezing point. Extrapolated viscosities from four known points were compared using the modified equation and the conventional method of plotting log of the viscosity against 1/T (absolute temperature). Six compounds were used in this comparison with the modified equation giving significantly better results near the freezing and boiling points. For the modified equation, errors of 0.3 to 7.3% were obtained as compared to errors of 0.4 to 16.7% for the conventional method