Solubilities of Gallic Acid and Its Esters in Water

The solubilities of gallic acid and its esters (methyl gallate, propyl gallate, and octyl gallate) in water were determined in the temperature range (273.15 to 363.15) K by a static analytical method. The concentrations of gallic acid and the esters in saturated solution were analyzed by reverse-phase high-performance liquid chromatography. An "S" type curve was found for the solubilities of gallic acid and octyl gallate in water over the investigated temperature range. An empirical equation was proposed to fit the data for gallic acid and octyl gallate. On the other hand, the data of methyl gallate and propyl gallate were in good agreement with the simplified λ−h equation.