The extraction of several mineral acids (HC104, HKOs, " 0 2 , HF, HCI, HBr, HI, TICK, (COOH),, H2S04, and H2Se04) into chloroform solutions of inethyldioctylaniinc has been studied. Oiily with perchloric acid can the results be explained solely in ternis of the formation of the 1 : 1 salt IZsNH+. Clod-. With the other acids, the organic phase may take up more acid than required for this salt; the reasons for this are discussed, and infrared evidence for ion pairing in the organic phase is given. Details of soine crystalline salts are presented.Solvent extraction with long-chain aiiiiries finds wide application in a number of fields,'S2 including thc study of the forniation of anionic coniplcxes in aqueous solution. 'The majority of such extractions irivolve aquroils acid solutions, with the consequent forniation of quaternary aiiiiiioiiiuni salts, which are virtually insoluble in water, but soluble in "inert" organic solvents such as chloroi'orni, brnzcne, carbon tetrachloride, and the like, in which the amine is usually dissolvcd to rcduce its high viscosity. An understanding of the interaction of such ariiiric solutions wit,h aqueous acids is of course fundanic~~tal to their use in other fields. Smith arid and othcrs12 havc reported thc extraction of different acids, and in sonic cases the cquilibriuni constant for lZ3XH.X(,) (1) A I~S S ( 0 , + H + ( W ) + X-(flq)has been incasured.2 In the present papcr, we discuss the extraction of a number of mineral acids into solutions of niethyldioctylaiiiine (11 IIOA), usually in chloroform. We have paid particular attention to the nature of the species in the organic phase, and to tho extraction of acid in ('xcess of that required by cq. 1. This phcmoiiicw)n has previously been described2 either i n ternis of the foriliation of species such as li,3X((ITX)2 in the organic phase, or siiiiply as the dissolution of ~X C C S S acid in the aninioniuin salt-dilucnt solvent systmi.With dibasic acids, two equilibria may be involved in the extraction A R3X(,,) + H2A(,q, -R&H.HA (e.g., bisulfate) (2) 2R3K(03 + H2Aa,,, -(R3SH)2A (e.g., sulfate) (3) Analytical and infrared results show that both of these processes occur in the systems studied by us. I n gcricral, oxalic acid is extracted better than sulfuric or selenic, which show very siniilar extractive behavior. Attempts were made to extract carbonic acid froin aqueous solution, both a t atmospheric and slightly higher prcssurc, but without forcing any detectable amounts of acid into the organic phase. As with monobasic acids, experinients with strong aqueous solutions of sulfuric and selenic acids showed that more acid could be extracted into the organic phase than corresponded to complete formation of the ammonium salt. With oxalic acid, the liniited solubility in water did not permit investigation of this effect. ExperimentalMaleTials. SIethyldioctylainine (British Hydrological Corp.) was shown by gas-liquid chroinatography (1-111. ethylene adipate column at 220°, nitrogen carrier gas) to contain no significant impurities and...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.