| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 155605 | Chemical Engineering Science | 2012 | 10 Pages |
The feasibility of reactive extraction of mono-caffeoylquinic acids (mono-CQAs) from aqueous extract solutions of tobacco wastes was studied. The mixed solvent system, initial pH, extractant concentration, complexation stoichiometry, equilibrium and mechanism were discussed. The results indicated that the extraction ability of extractants decreases in the order trialkylphosphine oxide (TRPO)>N235≈tributylphosphate (TBP)>trioctyl phosphate (TOP). Using a 1:1 ratio of 20% TRPO/kerosene to sample volume, one step recovered 94.9% of the mono-CQAs from an aqueous solution at pH 3. The complexation stoichiometry between TRPO and the mono-CQAs was 1:2 or 1:3, but the formation of 1:2 complexes was favored. The extraction equilibrium of the mono-CQAs was fit to a Henry isotherm, and the process was exothermic. Hydrogen-bond interactions between TRPO and mono-CQAs were confirmed by Fourier-transform infrared (FTIR) spectra, and the changes in the wavenumbers of absorbances increased with decreasing pKa values of the mono-CQAs.
► A novel reaction extraction method of mono-caffeoylquinic acids from tobacco wastes. ► 20% trialkylphosphine oxide/kerosene recovered 94.9% of mono-caffeoylquinic acids. ► Hydrogen-bond complexation stoichiometry was 1:2 or 1:3, but 1:2 formation was favored. ► Extraction equilibrium was fit to a Henry isotherm, and the process was exothermic. ► The changes in IR wavenumbers increased with decreasing pKa values of mono-CQAs.
