Diffusion coefficients of carboxylic acids in mixed solvents of water and 1-butanol

The diffusion coefficients of five carboxylic acids—formic acid, acetic acid, propionic acid, succinic acid, citric acid—in the phases of water saturated by 1-butanol (water-rich phase) and 1-butanol saturated by water (1-butanol-rich phase) at 25 °C were measured. The semi-empirical model suggested by Perkins–Geankoplis was applied to predict the value of the diffusion coefficients, while the equations of Wilke–Chang and Hayduk–Laudie were selected to calculate the diffusion coefficients in water and the models of Scheibel and Lusis–Ratcliff were for the diffusion coefficients in 1-butanol. By comparing the calculated and experimental data, it was found that the diffusion coefficients in the water-rich and 1-butanol-rich phases could be predicted very well with the combination of the equations of Hayduk–Laudie and Scheibel.