New insights in reactive extraction mechanisms of organic acids: An experimental approach for 3-hydroxypropionic acid extraction with tri-n-octylamine

• Published in: Separation and purification technology Vol. 179; pp. 523 - 532
• Main Authors: Chemarin, F., Moussa, M., Chadni, M., Pollet, B., Lieben, P., Allais, F., Trelea, I.C., Athès, V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2017; Elsevier
• Subjects: Active solvent; Chemical and Process Engineering; Engineering Sciences; In situ product recovery; Life Sciences; Organic acid; Solvent extraction; Tri-n-octylamine impurity; Tri-n-octylamine impurity; Solvent extraction; Active solvent; In situ product recovery; Organic acid
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2017.02.018

•Importance of H-bond donor character of the solvent in the complex stabilization.•Major impact of the solvent fraction on the extraction yield.•Effect of amine impurities transfer in the aqueous phase for low acid concentration.•Tri-n-octylamine impurities were identified to be n-octylamine and di-n-octylamine. A detailed study of 3-hydroxypropionic acid (3-HP) reactive extraction with tri-n-octylamine (TOA) is proposed for the first time. It aims at uncovering some solvent-solutes interactions and providing global mechanisms to better understand and design the reactive liquid-liquid extraction of 3-HP in a biotechnological process. Eleven solvents of similar molecular sizes and several chemical types (alcohols, esters and alkanes) were investigated to understand their role on the extraction ability. Alcohols were found to be the best solvents thanks to their H-bond donor characteristic and water loading that allowed good solvation of the acid-amine complexes. Further investigations were then undertaken, for n-decanol and oleyl alcohol as solvents, varying acid (0.0028–0.56mol/L corresponding to 0.25–50g/L) and amine (0–2.3mol/L corresponding to 0–100% v/v) concentrations. At 0.011mol/L (1g/L) of 3-HP, maximum extraction yields of 77% for n-decanol and 51% for oleyl alcohol were found for 0.46mol/L TOA (20% v/v). The initial TOA purity proved to have a major impact on the extraction yield at low initial acid concentration (<0.1mol/L=10g/L). Impurities from the TOA manufacturing process were identified as n-octylamine and di-n-octylamine and quantified in the aqueous phase after extraction. Their major effect on the extraction yield has been assessed (up to 86% decrease).