Extraction of Carboxylic Acids by ABC Extractants:Effects of Temperature,the Polarity of the Diluent,and the Ratio Between Extractant Components

摘要

A study was conducted of the temperature effect on the extraction of lactic and malic acid by acid-base couple (ABC) extractants in kerosene.Elevating the temperature from 30 deg C to 80 deg C decreases the extraction of both acids by ABC extractants comprising tricaprylyl amine (A336).The opposite effect is found for the extraction of lactic acid by primary amine-containing ABC extractants.It seems that temperature effect in the extraction of lactic and malic acids by ABC extractants results,at least partially,from competition for H-bonding.The study has also tested the effect of diluent polarity of ABC extractants by replacing kerosene there with octanol.It has shown that increased polarity affects the extraction of carboxylic acids mainly through stabilization of ion pairs and formation of H-bonds.Another studied effect was that of the ratio between the amine and the lipophilic acid in the ABC extractants.The results were found to depend on the acid-base properties,polarity,and structure of these components and on the properties of the extracted acid.