Liquid‐Liquid Extraction of Caproic and Caprylic Acid: Solvent Properties and pH

Abstract

Caproic acid (C6) and caprylic acid (C8) can be produced during anaerobic fermentation via chain elongation processes. This study focused on the selective recovery of C6 and C8 from a fermentation broth with liquid‐liquid extraction. Eight solvents, including alcohols, esters, an organophosphorus compound, and an amine, were evaluated based on their extraction efficiency and selectivity for C6 and C8. The highest extraction efficiency of C6 (46 %) and C8 (93 %) at pH 6.0 was achieved by 1‐octanol. Oleyl alcohol, 1‐decanol, and 1‐octanol had the highest selectivity for C6 and C8.