Solvent Extraction Equilibria of Certain 8-Quinolinols and Their Zinc(II) Chelates.

Abstract

Equilibrium distribution ratios have been determined for the extraction of zinc(ll) with 8-quinolinol, 2-methyl-8quinolinol, and 4-methyl-8-quinolinol into chloroform as a function of pH and reagent concentration at 25°C. Except in the case of 2-methyl-8quinolinol, which involved a simple 1:2 chelate, the extractable complexes were 1 :2 chelates to which a third molecule of reagent was coordinated. The overall formation constants of the zinc chelates in aqueous solution have been determined. The distribution coefficients of the chelates and chelate adducts are discussed in terms of structural influences. The analytical advantages of the use of 2-methyl-8-quinolinol in the extraction and subsequent determination of zinc(ll) are outlined.

Large Synergism of 3,5-Dichlorophenol in the Extraction of Gallium(III) with 2-Methyl-8-quinolinol Derivatives

“…6 2-Methyl-8-quinolinol (HMQ) is a useful analytical reagent available for the separation and determination of many metal ions in the presence of aluminium(III). 7,8 However, despite this advance, a few extraction constants have been determined, [9][10][11] and no detailed studies on the extraction equilibrium of gallium(III) with HMQ have been reported.…”

Extraction Behavior of Metal Cations Using 8-Quinolinol as an Extractant in Cyclopentyl Methyl Ether

“…As the extraction of metal cations using HQ proceeds via a proton-exchange reaction, the extraction reaction is fast [19,23].…”

“…On the basis of the results, the extraction behavior of metal ions using a chelating extractant 8-quinolinol (abbreviated as HQ, Figure 1) was studied in order to evaluate whether CPME can be used as an alternative solvent instead of toxic solvents like chloroform. HQ and its derivatives have extensively been used as chelating extractants in the field of analytical chemistry [14][15][16][17][18][19][20][21][22][23][24].…”

Extraction

“…Adduct formation with 8-quinolinol was shown to be necessary for the successful extraction of Zn with this reagent (107). With both 8-quinolinol and its 4-methyl derivative the extracted species is ZnL2-HL.…”