Correlation between structures and energies of cobalt(II) (Co) and manganese(II) (Mn) complexes with the hydroxyoxime extractant, LIX63 and/or the carboxylic acid extractant, Versatic acid 10 (VA10), were investigated using molecular dynamics (MD) calculations and density functional theory (DFT) calculations. The results of the MD calculations show that the form of the metal complex with both single and multiple extractants varied significantly with the numbers of coordinated extractant molecules and coordination sites. However, there was no correlation between the frequency of appearance of the metal complexes and the formation energy obtained from DFT calculations. In the case of Co or Mn complexes with LIX63 and VA10, these extractant molecules were tightly packed around each metal ion and there were little differences between the formation energies of the complexes. Our results suggest that structural and energetic stabilization is responsible for the synergistic effect of solvent extraction.
A sulfide type trident molecule together with a monopodal compound has been prepared to investigate the extraction behavior of silver. The present trident molecule has a weaker extraction ability than thiol and dithioether derivatives of previously reported tripodal extraction reagents. On the contrary, it exhibited a higher extraction ability than the corresponding monopodal molecule due to the structural effect of the trident framework. Both sulfide molecules did not exhibit any pH dependency for silver extraction. The trident molecule showed a 1 : 1 stoichiometry (trident molecule : silver), while the monopodal molecule gave a 2 : 1 stoichiometry (monopodal molecule : silver). The coordination site of the trident molecule was confirmed by 1H-NMR spectra before and after silver loading. The signal shifts for the protons of the methylene groups bounded to the sulfur atoms for the trident and monopodal compounds before and after silver loading were correlated with the formation of complexes. From the comparison of both molecules, the peak shift for the trident molecule included contributions not only from the functional groups but also from the structure of the trident framework.
The synergistic extraction of trivalent lanthanide ions (Ln(III)) with benzoylacetone (Hba) and trioctyphosphine oxide (TOPO) in an ionic liquid (IL), 1-butyl-3-methyl-imidazolium bis(trifluoromethanesulfonyl)imide ([Bmim][Tf2N]), has been investigated. The extractability of Ln(III) with Hba was significantly enhanced in the presence of TOPO. The composition and extraction constants of the extracted species for each Ln(III) in the presence or absence of TOPO were determined by 3-dimensional equilibrium analysis. It was found that all Ln(III) were extracted as cationic ternary complexes such as Ln(ba)2(TOPO)2+ or Ln(ba)(TOPO)42+ with Hba and TOPO, while Ln(III) was extracted as a neutral or cationic species such as Ln(ba)3 or Ln(ba)2+ with Hba alone. The formation constants of the cationic ternary complexes in the IL were calculated from the corresponding extraction constants obtained, indicating that Lu(ba)(TOPO)42+ is the most stable complex in the IL. Separation efficiency between different Ln(III) was also discussed on the basis of the extraction constants. The result demonstrated that theHba-TOPO[Bmim][Tf2N] system presented here is superior in the separation between heavier Ln(III).
The interfacial tensions of aqueous two-phase systems (ATPS) are commonly much lower than those of common oil/water interfaces. Micrometer- to mm-sized particles tend not to pass through liquid/liquid interfaces and tend to be trapped there. In the present study, the passing of μm-sized ferromagnetic and paramagnetic particles through ATPS interfaces was examined using a magnetic force by microscope observation. Ferromagnetic particles were aggregated at the ATPS interface under a magnetic field. Mn2+-adsorbed cation-exchange resin particles are not ferromagnetic but paramagnetic, and they were not aggregated. The individual Mn2+-adsorbed particles were drawn down from the interface by a downward magnetic force and then released. The forces on the particles, the gravitational force, the buoyancy, the magnetic force, and the force caused by the interfacial tension, were calculated or estimated from the experimental results. The present method is a fundamental study to develop a separation method for μm-sized particles using liquid/liquid interfaces.
Succinic acid and its ester have been considered as a renewable feedstock for chemical derivatives. A biotechnological production route for succinic acid has become of interest as a sustainable alternative to the chemical route. However, its hydrophilicity makes the separation of succinic acid from the fermentation broth difficult. In this study, to recover succinic acid from the fermentation broth, an aqueous two-phase system (ATPS) composed of ethanol and salts was used, and then the extracted succinic acid was esterified with ethanol because its ester had different physico-chemical properties that helped in its purification. In the ATPS, ammonium sulfate gave the highest extractability. Succinic acid was found to be co-extracted with water to the ethanol-rich phase. In a model experiment in the absence of water, succinic acid was successfully esterified with ethanol and the kinetics obeyed a pseudo-first-order consecutive reaction. Then the esterification of succinic acid using the ethanol-rich phase after the aqueous two phase extraction was carried out. In the case of the ATPS having a high extractability, the conversion of succinic acid and the yield of the di-ester were relatively low due to the large amount of co-extracted water. It was found that the water content was a key parameter in the esterification reaction.
Extraction of rutin from Ruta graveolens L. leaves was performed in choline chloride based deep eutectic solvents (DESs). Firstly, rutin extraction was performed in five different DESs; pure DESs and with different amounts of water added (25% and 50% v/v), for different times (1 h, 3 h and 6 h) in order to find the best DES for further optimization. Choline chloride plus citric acid (1 : 1) was shown to be best DES and optimization of rutin extraction was performed using response surface methodology (RSM) based on the selected solvent and applying different extraction parameters: extraction time, temperature and water content. The rutin content was determined by HPLC and varied from 0.55 g/100 g of plant to 1.81 g/100 g of plant depending on the applied conditions. The best conditions for rutin extraction were found to be: a temperature of 70°C, an extraction time of 52 min and a water content of 27 % for the extraction of 1.88 g /100 g plant.
Solvent extraction of lithium (Li) from salt lake brine was investigated by employing tributyl phosphate (TBP) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-TFSI). High extraction efficiency of Li was obtained from the brine containing co-existed metals. The extraction of Li was proceeded by solvation of Li with TBP followed by cation exchange with the ionic liquid. The purity of Li was increased to 85.1% after two extraction – stripping processes of the present extraction system.
We report here on hydrophobic ionic liquids (ILs) which enhance the productivity of paclitaxel and the related taxanes of 10-deacetyl baccatin III, baccatin III and cepharomannine with in situ extraction from an aqueous medium in the suspension cell culture of Taxus cuspidata in the IL-medium two phase culture system. Two aliphatic ILs of N-methyl-n-propylpiperidinium bis(trifluoromethane-sulfonyl)imide (PP13-TFSI) and N-methyl-n-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P14-TFSI) were used. It was found that the two ILs had no cytotoxicity and enhanced productivity of paclitaxel and the related taxanes in the cell culture. In particular, the more hydrophobic P14-TFSI, which enhanced the productivity of paclitaxel and the total taxanes by a factor of more than 2 compared to PP13-TFSI, could be an effective extractant.