Distribution of Cu(II) between Buffered Aqueous Phases and Organic Phases Containing N,N’-ethylenebis(4-propionyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine (H2PrEtP) in Chloroform

Abstract

Complexation of Copper (II) ions from aqueous media into chloroform solution of N,N’-ethylenebis(4-propionyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine) (H2PrEtP) Schiff base in chloroform was studied. Effect of various parameters for the extraction such as pH of aqueous media, concentration of the ligands and concentration of Cu(II) were all investigated alongside the synergistic effect of 4-propionyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one (HPrP) under a well-defined extraction condition. Complexation of Copper (II) ions was found to be highly dependent on pH of aqueous media and occurred more readily in acidic media. Single ligand complexation gave a pH½ (pH at which 50% extraction occurred) of 4.57 with the partition coefficient statistically determined to be LogDCuH2PrEtP 1.56±0.01 and extraction constant (Log Kex) CuH2PrEtP -3.25±0.10. Complexation with mixed ligand system gave a pH½ of 3.0, partition coefficients LogDCuH2PrEtP/HPrP of 1.70±0.05 and extraction constant Log KexCuH2PrEtP/HPrP of -3.12±0.10 showing that the complexetion of Cu(II) was slightly higher in the mixed ligands system. Optimum concentration of 3.5×10-2M H2PrEtP which gave 97.61% E was observed on varying the ligand concentration in the absence of the synergist while in the presence of the synergist, optimum concentration of 4.0×10-2 M which corresponds to 98.53% E was observed for the main ligand. Variation in synergist concentration gave optimum result of 97.85% E at 2.25×10-2 M HPrP. Analysis of slope was used to predict stoichiometry of the extraction reactions and to propose extracted metal complexes structure in both single and mixed ligands system as Cu(HPrEtP)o and Cu(HPrEtP.HPrP)o respectively.