Glycerol ethers as hydrotropes and their use to enhance the solubility of phenolic acids in water

The use of glycerol ethers (with alkyl side chain ranging from one to six methyl groups) as hydrotropes to enhance the solubility of gallic and syringic acids in water was here studied. These compounds were selected by their intrinsic interest and for serving as models for lignin fractions. The results obtained were compared against traditional co-solvents, demonstrating the exceptional hydrotropic ability of glycerol ethers. Setschenow constants show that the hydrophobicities of both solute and hydrotrope play an important role in the solubility enhancement by hydrotropy, shedding light into its molecular mechanism.