Anion Effect on the Solvent Extraction of Alkali Cations with Dibenzo-18-crown-6 in 1,2-Dichloroethane. Voltametric and Spectroscopic Analysis

RODRIGO A IGLESIAS; SERGIO A DASSIE; LIDIA M YUDI; ANA M BARUZZI

ANALYTICAL SCIENCES

Año: 1998 vol. 14 p. 231 - 231

0910-6340

span lang="en" style="FONT-SIZE: 11pt; FONT-FAMILY: Arial; mso-fareast-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">The alkali cations (M+) extraction process from water to 1,2-dichloroethane (DCE) with dibenzo18-crown-6 (DB18C6)using either picrate (Pi-) or2,4-dinitrophenolate (DNP-) as counter ions (A-) is analyzed. Picrates are extracted in a higher extent as a consequence of its higher hydrophobicity. Extraction constants (Kext) were determined analyzing the organic phase resulting of the extraction process, either spectrophotometrically or voltammetrically against an aqueous phase containing LiCl. A very good agreement between both methods was obtained except for Cs+. The extraction using DNP- can only be performed provided it is initially present in the aqueous phase. On the other hand,if HDNP is present in the organic phase the e