Calculation the surface tension of heptane, eicosane, docosane, tetracosane, and their asymmetric mixtures.

A method to calculate and predict the surface tension of n-alkanes including heptane, eicosane, docosane, tetracosane, and their asymmetric mixtures has been proposed. Reduced coordinates, sigma* and T*, where sigma* is the reduced surface tension and T* is the reduced temperature, are introduced for the prediction of surface tension. According to the phenomenological scaling and considering the law of corresponding states correlation, these reduced coordinates result in a single curve for the surface tension as a function of temperature. In the correlation the melting temperature, Tm, is applied as the corresponding temperature for these substances and their mixtures. The relationship between sigma* and T* has a linear form and is expressed by sigma* = a + bT*, where a and b are temperature-independent constants. With this relationship the predicted values of surface tension of these substances and their mixtures are in good agreement with experimental ones. %AAD, percent average absolute deviation, for these four pure n-alkanes is 1.02% and for their four asymmetric mixtures is less than 0.70%.