Extractions of Alkaloids Codeine and Caffeine with [Bmim][BF4]/Carbohydrate Aqueous Biphasic Systems as a Novel Class of Liquid-Liquid Extraction Systems

摘要

Liquid-liquid equilibrium (LLE) data for several carbohydrate + IL aqueous biphasic systems, including the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]- [BF4) and six carbohydrates: monosaccharides (D-(+)-glucose, D-(-)-fructose, L-(+)-arabinose, and D-(+)-xylose) and disaccharides (sucrose and maltose) were obtained at different temperatures. With fitting the obtained LLE data to a Setschenow-type equation, the positive (soluting-out effect) soluting-out coefficients, ks(,) were obtained. The obtained k(s) values increase by decreasing temperature as well as the hydrophobicity of the sugars. Extractions of two alkaloids, including codeine and caffeine, with [Bmim][BF4]/carbohydrate aqueous biphasic systems were examined. The effect of temperature, tie-line length (TLL), hydrophilicity of sugars, and physicochemical properties of alkaloids on the partition coefficient and standard molar Gibbs free energy changes (Delta(tr)G(m)(0)) were studied. Both codeine and caffeine had high tendency for hydrophobic IL-rich phase, and this orientation increased with increasing TLL, hydrophilicity of sugars, and decreasing temperature.