Freeze-out extraction of monocarboxylic acids from water into acetonitrile under the action of centrifugal forces

Abstract

It is established that the efficiency of the freezing-out extraction of monocarboxylic acids С3–С8 and sorbic acid from water into acetonitrile increases under the action of centrifugal forces. The linear growth of the partition coefficient in the homologous series of С2–С8 acids with an increase in molecule length, and the difference between the efficiency of extracting sorbic and hexanoic acid, are discussed using a theoretical model proposed earlier and based on the adsorption–desorption equilibrium of the partition of dissolved organic compounds between the resulting surface of ice and the liquid phase of the extract. The advantages of the proposed technique with respect to the degree of concentration over the method of low-temperature liquid-liquid extraction are explained in light of the phase diagram for the water–acetonitrile mixture.