Affiliation:
1. Southwest State University
Abstract
Purpose of the study. Based on the results of the study of salts of 2(4)-octylaminopyridines (2(4)-OAP) by physical methods and their distribution in the two-phase system water-chloroform, establish the patterns of ion-exchange extraction of anions using aromatic amines.Methods. Chemical synthesis of 2(4)-OAP and their halides, spectrophotometry to determine the concentration of 2(4)-OAP in the aqueous and organic phase, characterization of 2(4)-OAP and their halides by IR, PMR and ESCA spectroscopy.Results. Synthesized by original methods and identified 2(4)-OAP and their halides. The distribution constants of 2-aminopyridine and 4-OAP salts with a singly charged anion in the water–chloroform two-phase system were determined. It is shown that the obtained constants increase in the following order: F-<Сl-<NO3-<Br-<ClO4-<SCN-<I-. In this case, a linear correlation between the logarithms of the constants and the hydration energy of anions in thisseries as a whole, which is typical for extraction with aliphatic amines and quaternary ammonium bases (FABs), is not observed. The results of the study of 2(4)-OAP halides by physical methods indicate a redistribution of the electron density in the aromatic cation depending on the nature of the anion, which ensures the selectivity of the extraction of “soft” (according to Pearson) 2(4)-OAP anions from aqueous media.Conclusion. The patterns of anion-exchange extraction of 2(4)-OAP, as well as, apparently, other aromatic amines, on the one hand, and aliphatic amines and PAO, on the other hand, coincide only with respect to “hard” anions. The situation changes during the extraction of "soft" anions. Due to the specificity of interionic interaction, aromatic amines are more selective with respect to "soft" anions, including, apparently, some acid complexes of "soft" metal cations, for example, with respect to halide complexes of platinum and other rare metals that are extracted by 2(4)-OAP better than by aliphatic amines and PAO.
Publisher
Southwest State University
Reference21 articles.
1. Ageeva L. S., Borsch N. A., Kuvardin N. V. 2(4)-Aminopyridines as Ligands in the Coordination and Extraction Chemistry of Platinum Metals. Exploring Chemistry with Pyridine Derivatives, 2023. Jan. https://doi.org/10.5772/intechopen.106376
2. Borsch N. A. Teoriya i praktika ekstraktsionnykh metodov [Theory and practice of extraction methods]. Rep. ed. Alimarin I. P., Bagreev V. V. Moscow, Nauka Publ., 1985. 269 p.
3. Borshch N. A., Petrukhin O. M., Sokolov A. B., eds. Issledovanie khimizma ekstraktsii iridiya 2-Oktilaminopiridinom [Study of the chemistry of iridium extraction with 2-octylaminopyridine]. Zhurnal neorganicheskoi khimii = Journal of Inorganic Chemistry, 1981, vol. 26, no. 3, pp. 734–743.
4. Seregina I. F., Petrukhin O. M., Formanovskiy A. A., eds. 4-Oktilaminopiridin – ekstraktsionnyi reagent na iridii [4-Octylaminoperidine - extraction reagent for iridium]. Doklady AN SSSR = Documents of the Academy of Sciences of the USSR. 1984, vol. 275, no. 2, pp. 385–387.
5. Ageeva L. S., Borshch N. A., Kuvardin N. V., eds. Vzaimodeistvie ionov platinovykh i perekhodnykh metallov c 2(4)-aminopiridinami v vodnykh rastvorakh v usloviyakh, priblizhennykh k protsessam ikh ekstraktsionnogo vydeleniya i razdeleniya [Interaction of platinum and transition metal ions with 2(4)-aminopyridines in aqueous solutions under conditions similar to processes their extraction isolation and separation]. Zhurnal fizicheskoi khimii = Journal Physical Chemistryб 2023, vol. 97, no. 1. P. 24.