Recovery of erythromycin from aqueous solutions with an ionic liquid and high-pressure carbon dioxide

Recovery of erythromycin from aqueous solutions was studied in two steps: (i) single- and multi-stage extraction of erythromycin from an aqueous solution with a hydrophobic ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [BMPyrrol][Tf2N], as a function of pH and feed to solvent volume ratio, and (ii) high-pressure CO2 extraction of erythromycin from the ionic liquid, as a function of pressure, temperature and presence of water. Furthermore, data on the mutual solubilities of the hydrophobic ionic liquid and water, as well as on the solubility of erythromycin in [BMPyrrol][Tf2N], were obtained. The chemical stability of erythromycin in water-free and water saturated ionic liquid was tested. These results allowed the evaluation of the coupling of liquid-liquid and high-pressure CO2 extractions. (C) 2011 Elsevier B.V. All rights reserved.