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.

► Recovery of erythromycin from aqueous solutions using ionic liquid and high-pressure CO2.
► As pH values decreased partition yield of erythromycin between IL and aqueous phase rapidly increased.
► High-pressure CO2 extraction rate increases with increasing pressure.
► Possibility to integrate liquid extraction and recovery of erythromycin using high-pressure CO2 was studied.