Influence of Alkyl Chain Length and Structure on the Extraction of Copper(II) from Aqueous Acid by 5-Alkyl-2-hydroxybenzaldoximes in Hydrocarbon Solvents: Diffusion Coefficients of Extractants and Their Complexes
✍ Scribed by T.Andrew Ainscow; Isidoro Aldalur; Anthony E Beezer; Joseph A Connor; Nichola C Garbett; John C Mitchell; Adelle L Page; Neil Tindale; Kristian A Turner; Richard J Willson
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 53 KB
- Volume
- 213
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
Measurement of the kinetics of extraction of copper(II) by 19
different 5-alkyl-2-hydroxybenzaldoximes (alkyl is C 7 H 15 and C 9 H 19 ) from acidic (hydrogen sulfate buffer) aqueous solution in the range pH 3.4 -2.0, into 20% v/v toluene in n-hexane is reported. The lowering of the interfacial tension has been measured in some cases. The solubility of the extractants in water has been measured spectrophotometrically. A modified Taylor-Aris dispersion technique has been used to measure the diffusion coefficients in nhexane and Orfom SX7 of some of the extractants and of the copper(II) complexes which they form. At low initial bulk concentrations (<10 mol m ؊3 ) of the extractants, the rate of extraction is controlled by the rate of diffusion of the extractant from the bulk to the organic-aqueous interface. The diffusion coefficient is related to the steric bulk of the alkyl substituent. At higher initial bulk concentrations (200 mol m ؊3 ) of the extractants, when the interface is saturated, the rate of extraction is inversely related to the apparent steric bulk of the alkyl substituent.