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The separation of structurally similar compounds, such as cholic acid (CA) and deoxycholic acid (DCA), is challenging due to their nearly identical physicochemical properties. This study demonstrates a synergistic 'push and pull' strategy with an ionic liquid (IL) biphasic system for significantly enhanced CA/DCA separation efficiency. Ethyl acetate was selected as the feed solvent to 'push' CA into the IL-rich extractant phase, while the IL 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl) was chosen to 'pull' CA due to their strong hydrogen bonding interaction. This 'push and pull' system yielded a remarkable CA/DCA selectivity up to 47.8, much higher than the case using n-butanol which pulls both CA and DCA. The underlying separation mechanism was elucidated through computational screening with COSMO-RS, NMR analysis, and solvatochromic measurements. Results revealed the critical roles of specific hydrogen bonding between the chloride anion of [EMIM]Cl and the hydroxyl/carboxyl groups of CA/DCA, along with nonspecific interactions between the feed solvent and CA/DCA. Thermodynamic analysis of the phase transfer process confirmed the 'push and pull' synergy is energetically favorable for preferentially transferring CA from the ethyl acetate feed solution into the IL-rich extractant phase. Multi-stage simulation indicated that 99% purity and recovery of both CA and DCA can be obtained through this biphasic system under optimized conditions. Overall, strategically tuning both the feed solvent and IL extractant could significantly enhance the separation efficiency of structurally similar compounds while minimizing solvent and energy consumption. This 'push and pull' approach may shed light on improving separation processes for other structural analogues. [ABSTRACT FROM AUTHOR]

Separation of high value bioactive compounds is a viable route to make full use of the biomass resources and improve the profitability. However, the sparing aqua- and lipo-solubility of the bioactive compounds makes their separation really challenging. Considering that ionic liquids show good solubility of biomass and could easily form biphasic systems with organic solvents, an ionic liquid (IL)-based biphasic system consisting of ionic liquid, water and ethyl acetate is proposed in this study. Ginkgolide homologues were selected as model compounds to evaluate its practicality. Adequate distribution coefficients, relatively high extraction capacity and selectivity were obtained with the novel biphasic system. The improved distribution coefficients of the ginkgolides are mainly attributed to the multiple interactions between ginkgolide and IL, which were confirmed by means of quantum chemistry calculations. Moreover, the effect of the interactions between ginkgolides and the extraction solvent on the selectivity coefficient was studied by measuring the Kamlet–Taft parameters of the extraction solvent. Based on the results of fractional extraction, which was simulated by calculation and validated by experiments, as well as the comparison of organic solvent consumption, the employed IL-based extraction would be a valid and clean method as an alternative to chromatographic methods for separating bioactive compounds in large-scale operations. It is noteworthy that the amount of organic solvents consumed with this method was supposed to be less than 1/11 of the most widely used chromatographic method. [ABSTRACT FROM AUTHOR]

High quality epitaxial thin films of the quasi-one dimensional conductor K 0.3 MoO 3 have been successfully grown on SrTiO 3 (100), SrTiO 3 (110), and SrTiO 3 (510) substrates via pulsed laser deposition. Scanning electron microscopy revealed quasi-one dimensional rod-shaped structures parallel to the substrate surface, and the crystal structure was verified by using X-ray diffraction. The temperature dependence of the resistivity for the K 0.3 MoO 3 thin films demonstrates a metal-to-semiconductor transition at about 180 K. Highly anisotropic resistivity was also observed for films grown on SrTiO 3 (510)., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)