Separation of glycolic acid from glycolonitrile hydrolysate by reactive extraction with tri- n-octylamine

• Published in: Separation and purification technology Vol. 49; no. 1; pp. 20 - 26
• Main Authors: Yunhai, Shi, Houyong, Sun, Deming, Lu, Qinghua, Le, Dexing, Chen, Yongchuan, Zhou
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2006; Elsevier Science
• Subjects: Applied sciences; Chemical engineering; Exact sciences and technology; Extraction; Glycolic acid; Glycolonitrile hydrolysate; Reactive extraction; Separation; Tri- n-octylamine; Extraction; Tri- n-octylamine; Separation; Glycolonitrile hydrolysate; Glycolic acid; Reactive extraction; Loading; Mass action law; Extract; Tri-n-octylamine; Phase equilibrium; Modeling; Liquid liquid equilibrium
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2005.08.002

The extraction of glycolic acid from an aqueous glycolonitrile hydrolysate with tri- n-octylamine (TOA) in diluents of 1-octanol and kerosene was investigated in this article. The influences of TOA concentration, extraction temperature and phase ratio, O/W (volume ratio of organic phase to aqueous phase) on the acid distribution coefficient and loading factor of TOA were measured. The liquid-liquid equilibrium data of glycolic acid distributed between the extract phase and the raffinate phase were determined, and correlated with a model developed from the mass action law and suitable assumptions. Additionally, the acid loaded extractants were regenerated by using pure water as the back-extractant. The results show that lower temperature is beneficial to the extraction of glycolic acid from the hydrolysate, while higher temperature and phase ratio (O/W) are favorable to the back-extraction.