Solvent effect on the self-adduct extraction of zinc (II) with 5-(4-nitrophenylazo)-7-(4-ethyl-1-methyloctyl)-8-quinolinol

• Published in: Bunseki kagaku Vol. 47; no. 2; pp. 101 - 107
• Main Authors: OHASHI, Kousaburo, MATSUTA, Nobuhiro, IMURA, Hisanori, YAMAMOTO, Hiroshi, HIRATANI, Kazuhisa
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Science and Technology Agency 01.02.1998
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.47.101

The extraction of zinc(II) with 5-(4-nitrophenylazo)-7-(4-ethyl-l-methyloctyl)-8-quinolinol(HNEQ) was investigated using chloroform, 1, 2-dichloroethane, isobutylmethyl ketone (MIBK), and 1-octanol as diluents. HNEQ exhibited a higher extractability toward zinc(II) than did 8-quinolinol and Kelex 100. The extractability of zinc(II) with HNEQ increased in the following order of chloroform < 1, 2-dichloroethane < MIBK < 1-octanol. The extraction constants Kex, n = [Zn(NEQ)2(HNEQ)n]org[H+]2/[Zn2+][HNEQ](2+n)org and the formation constants (βs, n= [Zn(NEQ)2(HNEQ)n]org/[Zn(NEQ)2]org [HNEQ]norg) of the self-adduct complexes [Zn(NEQ)2(HNEQ)n] in the organic solvents were dependent on the characteristics of the organic solvents. MIBK and 1-octanol provided larger formation constant of the self-adduct complex than did chloroform and 1, 2-dichloroethane. This may be ascribed to the coordination of MIBK or 1-octanol to the Zn(II)HNEQ complex and/or to the hydration of Zn(II)-HNEQ complex with MIBK or 1-octanol. It was also found that Zn(II)-HNEQ strongly absorbs at 522 nm (λmax=8.40 × 104 cm-1mol-11, chloroform) and 543 nm (λmax=8.40 × 104 cm-1 mol-11, 1-octanol).