(735c) Continuous Intensified Solvent Extraction of Biomolecules Using Hydrophobic Ionic Liquids

In pharmaceutical processes the high cost associated with downstream processing aimed at the purification and recovery of target products is one of the major issues limiting the widespread use of many bio-base products [1]. Separation processes and purification stages usually require numerous steps associated with high energy and chemicals consumption and typically represent a large percentage of the cost of the final product. Modern pharmaceutical manufacturing organizations would like separations that can integrate with continuous upstream flow synthesis and downstream isolation procedures, replacing current batch systems. Continuous manufacturing offers a range of advantages over batch, including speed, flexibility and safety. Solvent extraction remains one of the most attractive separation techniques due to its versatility, simplicity and effectiveness [2]. Continuous solvent extraction can be intensified with the application of small-scale two-phase contactors, where the reduction of the apparatus size leads to a range of benefits, such as high mass transfer rates and reduced solvent use. Small channel contactors have been successfully employed in the past for metal extractions [3].

Hydrophilic pharmaceutical molecules are difficult to extract from aqueous media with traditional organic solvents. The choice of solvent is often limiting as it needs to be inert for medical purposes. Ionic liquids have recently been proposed as alternatives, because of their numerous benefits including, low volatility and high chemical stability [4]. In this work we investigate the separation of hydrophilic amino acids, with hydrophobic imidazolium based ionic liquids using macrocyclic compounds as extractants. For amino acid L-tryptophan, the highest partition coefficients were obtained at pH values less than 2.38, where the amino acid was in its cationic form. Continuous extraction experiments were carried out in intensified small channels. The flow patterns of the aqueous and the ionic liquid phases were studied for total volumetric flowrates from 0.001 to 0.1 m³/s and volume fraction of the two phases ranging in a 0.5 mm channel. For the conditions were plug flow was established, mass transfer experiments were carried out for different residence times.

Acknowledgements: Y.V. Phakoukaki would like to thank EPSRC and Johnson Matthey for her studentship

References:

[1] Behme, S. (2015). Manufacturing of pharmaceutical proteins. Weinheim: Wiley-VCH, pp.68-95.

[2] Poole, C. and Poole, S., 2010. Extraction of organic compounds with room temperature ionic liquids. Journal of Chromatography A, 1217(16), pp.2268-2286.

[3] Tsaoulidis, D. and Angeli, P. (2015). Effect of channel size on mass transfer during liquid–liquid plug flow in small scale extractors. Chemical Engineering Journal, 262, pp.785-793.

[4] Ghandi, K., 2014. A Review of Ionic Liquids, Their Limits and Applications. Green and Sustainable Chemistry, 04(01), pp.44-53.