A method of removing a carboxylic acid from a liquid that contains a tertiary amide solvent includes a step of contacting the liquid with an extraction medium comprising an amine. The amine is immiscible with both water and the tertiary amide solvent, and the contacting step forms a de-acidified phase containing the tertiary amide solvent and a phase containing the extraction medium and the carboxylic acid. Both the liquid that contains the tertiary amide solvent and the de-acidified phase may also contain a sucrose-6-acylate.