N-Alkyl substituted dithizone

The extraction rate constants for Ni(II) and Zn(II) with n-alkyl substituted dithizone did not obey the above relationship (see Fig. 4). In addition, the calculated value for k in the extraction of Zn(II) with dihexyldithizone gave an impossibly large value of 10 s. ... 

The extraction systan that was measured by the HSS method for the first time was the extraction kinetics of Ni(II) and Zn(II) with n-alkyl substituted dithizone (HL) [28]. The observed extraction rate constants linearly depended on both concentrations of the metal ion [M +] and the dissociated form of the ligand [L ]. This seemed to suggest that the rate-determining reaction was the aqueous phase complexation that formed 1 1 complex. However, the observed extraction rate constant k was not... 

H. Watarai and H. Preiser, Effect of stirring on the distribution equilibria of n-alkyl-substituted dithizones, J. Am. Chem. Soc., 105,191-194 (1983). 

FIGURE 2.22 Dependence of the extraction rate constants, of Zn(II) and Ni(II) on the number of carbon atoms in the substitution of n-alkyl dithizones. The solid lines trace the observed values and the broken lines the values predicted from the aqueous mechanism. 

---