ISSN 1070-3632, Russian Journal of General Chemistry, 2009, Vol. 79, No. 12, pp. 2599–2605. © Pleiades Publishing, Ltd., 2009. Original Russian Text © R.A. Cherkasov, A.R. Garifzyanov, S.V. Leont’ev, R.R. Davletshin, S.A. Koshkin, 2009, published in Zhurnal Obshchei Khimii, 2009, Vol. 79, No. 12, pp. 1973–1979. 2599 Extraction of Scandium Ions by New Aminophosphinyl Extractants R. A. Cherkasov, A. R. Garifzyanov, S. V. Leont’ev, R. R. Davletshin, and S. A. Koshkin Kazan State University, ul. Kremlevskaya 18, Kazan, 420008 Tatarstan, Russia e-mail: rafael.cherkasov@ksu.ru Received April 21, 2009 Abstract—Extraction of Sc(III) ions by new aminophosphinyl compounds containing one or two methylenediorganylphosphinyl groups at the nitrogen atom was studied with a target of the development of effective and selective extractants of trace elements. The selection of extractants was due to their high hydrolytic stability in the acid media, commonly used at the extraction of metal ions in the industrial hydrometallurgical processes. The study of extraction of hydrogen chloride and nitric acids with the selected aminophosphinyl compounds allowed a discovery of substances with the low basicity, which were characterized by the low coefficient of the acids extraction. Highly effective extractants of Sc(III) were found possessing high coefficients of extraction and high degree of selectivity in the separation of Sc(III) ion from the ions of satellite metals. The problems, whose solution requires application of effective and selective industrial extractants of new generation include creation of the new complex hydrometallurgical processes for processing the ore of rare and trace elements and the products of nuclear fission, and the ecology problems connected with the deep purification of waste water containing highly toxic and radioactive contaminants. An experience accumulated at the use of organophosphorus com- pounds such as tributyl phosphate and trioctyl- phosphine oxide for these purposes substantiates the urgency of studying the extraction properties of polydentate extractants possessing a phosphine oxide fragment. The lipophilic α-aminophosphine oxides (amino- phosphinyl compounds) synthesized by us and des- cribed in [1], fit to the requirements of the industrial extractants showing a high hydrolytic and thermal resistance, unlimited solubility in nonpolar organic solvents, effective interphase distribution, relatively low emulsifying power in the two-phase systems. At the same time it is noteworthy that although the processes of the liquid and membrane extraction of some metals, especially the ions of alkali metals by organophosphorus reagents, have been studied in detail [2–4], there is little information on the liquid and membrane extraction of trace elements. We decided to study initially the liquid extraction of some trace elements with the use of mono- and diphosphorylated amines of the general formula R 2 P(O)· CH 2 R 1 , where R= Hex (I, II, V, VI), cyclo-HexO (VIII, IX), Oct (VII), Dec (IV), p-Tol (III); R 1 = NOctCH 2 P(O)Hex 2 (I), NHOct (II, III), NHex(CH 2 ) 2 OH (IV), NOctCH 2 P(O)(Tol-p) 2 (V), NH(CH 2 ) 4 NHCH 2 · P(O)Hex 2 (VI), NH(CH 2 ) 6 NHCH 2 P(O)Oct 2 (VII), N(2-EtHex) 2 (VIII), and (CH 2 ) 2 NBut 2 (IX). As the substrate we selected the scandium ion. Scandium is a typical trace element. The techno- logy of scandium isolation commonly includes the method of extraction, and the search for new highly effective extractants for this element is an extremely urgent task. At present in the scandium hydro- metallurgy neutral organophosphorus compounds and highest aliphatic amines are used, and the processes of extraction with these extractants have been studied in detail and systematized [5–9]. At the same time, there are no published data on the use for the extraction of scandium of new highly effective and selective extractants of metal ions such as aminophosphoryl compounds earlier studied by us as the membrane penetration enhancers and the liquid extractants of the ions of alkaline, alkaline-earth, and noble metals [10–12]. DOI: 10.1134/S107036320912007X