Extraction of Organic Acids with Hydrophobic Eutectic Mixtures Containing Terpenoids and Decanoic Acid

In this study, we prepared eutectic mixtures containing decanoic acid as the hydrophobic hydrogen bonding donor, a lidocaine analog, and quaternary ammonium salt or terpenoid as the hydrophobic hydrogen bonding acceptor. The eutectic mixtures containing terpenoids, especially menthone, had very low viscosities. A series of monocarboxylic and dicarboxylic acid extractions were performed with the eutectic mixtures. The extractability of aliphatic monocarboxylic and dicarboxylic acids with eutectic mixtures containing terpenoids and decanoic acid was proportional to the hydrophobicities of their carboxylic acids. However, lactic acid was more extracted than acetic acid in a menthol-based eutectic mixture, even though lactic acid, a hydroxycarboxylic acid, is more hydrophilic than acetic acid, an aliphatic carboxylic acid.