Separation of Baicalein from Baicalin by Means of Solvent Extraction.

Kitazaki, Hironori; Ishimaru, Masayuki; Inoue, Katsutoshi; Yoshida, Kumiko

doi:10.1252/kakoronbunshu.22.287

Cited by 7 publications

(4 citation statements)

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“…In general, flavonoids are included in the root of certain plants such as Scutellaria root. However, no effective extraction process from natural materials has been established on an industrial scale (Kitazaki et al, 1994;Mishima et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Solubilities of Flavone and 3-Hydroxyflavone in Supercritical Carbon Dioxide

et al. 1997

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The solubilities of flavone and 3-hydroxyflavone in supercritical carbon dioxide (SC-CO2) were measured at 308.2 K and 318.2 K over the pressure range from 9.1 MPa to 25.3 MPa by a flow type apparatus, which can detect the concentrations of the solutes in a supercritical fluid. The solubilities were determined from the mass of solute trapped by decompressing and the volume of CO2. Solubility data were correlated by a solution model based on the regular solution model.

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Section: Introductionmentioning

confidence: 99%

Solubilities of Flavone and 3-Hydroxyflavone in Supercritical Carbon Dioxide

et al. 1997

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“…Only recently, other applications have been investigated, including the bench-scale or pilot-scale recovery of polar organics such as phenols, [7,8] and the separation of organic acids, [9,10] amino acids, [11] and flavonoids. [12] However, large-scale applications in the separation of polar solutes, such as ethers and phenols from, for example, phenol production line wastewater, which is the system under consideration for this project, do not yet exist, largely because the factors that would drive such an extraction process have not…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Bonding in Phosphine Oxide/Phosphate–Phenol Complexes

2010

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To develop a new solvent-impregnated resin (SIR) system for the removal of phenols and thiophenols from water, complex formation by hydrogen bonding of phosphine oxides and phosphates is studied using isothermal titration calorimetry (ITC) and quantum chemical modeling. Six different computational methods are used: B3LYP, M06-2X, MP2, spin component-scaled (SCS) MP2 [all four with 6-311+G(d,p) basis set], a complete basis set extrapolation at the MP2 level (MP2/CBS), and the composite CBS-Q model. This reveals a range of binding enthalpies (DeltaH) for phenol-phosphine oxide and phenol-phosphate complexes and their thio analogues. Both structural (bond lengths/angles) and electronic elements (charges, bond orders) are studied. Furthermore, solvent effects are investigated theoretically by the PCM solvent model and experimentally via ITC. From our calculations, a trialkylphosphine oxide is found to be the most promising extractant for phenol in SIRs, yielding DeltaH=-14.5 and -9.8 kcal mol(-1) with phenol and thiophenol, respectively (MP2/CBS), without dimer formation that would hamper the phenol complexation. In ITC measurements, the DeltaH of this complex was most negative in the noncoordinating solvent cyclohexane, and slightly less so in pi-pi interacting solvents such as benzene. The strongest binding is found for the dimethyl phosphate-phenol complex [-15.1 kcal mol(-1) (MP2/CBS)], due to the formation of two H-bonds (P=OH-O- and P-O-HO-H); however, dimer formation of these phosphates competes with complexation of phenol, and would thus hamper their use in industrial extractions. CBS-Q calculations display erroneous trends for sulfur compounds, and are found to be unsuitable. Computationally relatively cheap SCS-MP2 and M06-2X calculations did accurately agree with the much more elaborate MP2/CBS method, with an average deviation of less than 1 kcal mol(-1).

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“…[6,7] Bench-scale or pilot-scale recovery of polar organics like organic acids, [8,9] amino acids, [10] and flavonoids has also been realized. [11] To enhance extraction, complex-forming extractants can be added to the organic phase. Complex formation inside the organic solvent increases the overall equilibrium concentration of solute in the SIR, which significantly enhances the overall extraction capacity.…”

Section: Introductionmentioning

confidence: 99%

Complexation of Phenol and Thiophenol by Amine N‐Oxides: Isothermal Titration Calorimetry and ab Initio Calculations

et al. 2010

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To develop a new solvent-impregnated resin (SIR) system for removal of phenols from water, the complex formation of dimethyldodecylamine N-oxide (DMDAO), trioctylamine N-oxide (TOAO), and tris(2-ethylhexyl)amine N-oxide (TEHAO) with phenol (PhOH) and thiophenol (PhSH) is studied. To this end we use isothermal titration calorimetry (ITC) and quantum chemical modeling (on B3LYP/6-311G(d,p)-optimized geometries: B3LYP/6-311+G(d,p), B3LYP/6-311++G(2d,2p), MP2/6-311+G(d,p), and spin component scaled (SCS) MP2/6-311+G(d,p); M06-2X/6-311+G(d,p)//M06-2X/6-311G(d,p), MP2 with an extrapolation to the complete basis set limit (MP2/CBS), as well as CBS-Q). The complexes are analyzed in terms of structural (e.g., bond lengths) and electronic elements (e.g., charges). Furthermore, complexation and solvent effects (in benzene, toluene, and mesitylene) are investigated by ITC measurements, yielding binding constants K, enthalpies ΔH(0), Gibbs fre energies ΔG(0), and entropies ΔS(0) of complex formation, and stoichiometry N. The ITC measurements revealed strong 1:1 complex formation between both DMDAO-PhOH and TOAO-PhOH. The binding constant (K=1.7-5.7×10(4) M(-1)) drops markedly when water-saturated toluene was used (K=5.8×10(3) M(-1)), and π-π interaction with the solvent is shown to be relevant. Quantum mechanical modeling confirms formation of stable 1:1 complexes with linear hydrogen bonds that weaken on attachment of electron-withdrawing groups to the amine N-oxide moiety. Modeling also showed that complexes with PhSH are much weaker than those with PhOH, and in fact too weak for ITC determination. CBS-Q incorrectly predicts equal or even higher binding enthalpies for PhSH than for PhOH, which invalidates it as a benchmark for other calculations. Data from the straightforward SCS-MP2 method without counterpoise correction show very good agreement with the MP2/CBS values.

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Separation of Baicalein from Baicalin by Means of Solvent Extraction.

Cited by 7 publications

References 0 publications

Solubilities of Flavone and 3-Hydroxyflavone in Supercritical Carbon Dioxide

Solubilities of Flavone and 3-Hydroxyflavone in Supercritical Carbon Dioxide

Hydrogen Bonding in Phosphine Oxide/Phosphate–Phenol Complexes

Complexation of Phenol and Thiophenol by Amine N‐Oxides: Isothermal Titration Calorimetry and ab Initio Calculations

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