n-Octanol-water partition coefficients, aqueous solubilities and Henryʹs law constants of fatty acid esters

The aqueous solubility and n-octanol-water partition coefficient of fifteen fatty acid esters are determined by the RP-HPLC method. Aqueous solubilities decrease from 5.7 × 10−5 M for methyl caprate to 5.3 × 10−12 M for methyl behenate while the log Kowʹs increase from 4.4 to 10. Special attention is given to satisfying the statistical assumptions underlying the establishment of the calibration line. Residual plots show that in this case small systematic errors are introduced rapidly even if the selected substances for the calibration line are similar in their physical properties to the fatty acid esters. Combining previously determined vapour pressure data with the estimated solubility values allows for the estimation of Henryʹs law constants. Although the calculated values are not very accurate, it can be concluded that they are in general lower than those of the halogenated hydrocarbon solvents.