THE BEHAVIOUR-STRUCTURE RELATIONS IN THE EXTRACTION OF COBALT(II), NICKEL(II), COPPER(II) AND CALCIUM(II) BY KONOACIDIC ORGANOPHOSPHORUS EXTRACTANTS |
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Authors: | Qiu Dianyun Zheng Longao Ka Rongjun |
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Affiliation: | Changsha Research Institute of Mining and Metallurgy, Ministry of Metallurgical Industry , China P.O. Box 67, Changsha, Hunan, China |
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Abstract: | The reaction stoichiometrics were studied in the extraction of Co(II), Ni(II), Cu(II) and Ca(II) by n-octyl, 1-methylheptyl and 2-ethylhexyl hydrogen styrylphosphonates and di-2-ethylhexylphosphoric acid and 2-ethylhexyl hydrogen 2-ethylhexylphosphonate. The ultraviolet-visible and infrared spectra were recorded for these extractants and their complexes with the above metals. Based on the experimental data, an empirical relationship was established between the structure of the extractants and the extracting behavior: pH½ = ApKa + Bνp=0 - c where pKa and νp=0 are the acid dissociation constant of the extractants and the characteristic frequency of infrared absorption for the P=0 group, respectively. The values of A, B and C depend on the extracted metals. The analysis of the relationship between the steric effect of substituting groups and extracting power seems to indicate that the steric effect has been implied in the coefficients A, B and C. |
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