Distribution of U(VI) from Aqueous Solutions into Chloroform Solution of N,N’-Ethylenebis (4-butanoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine) Schiff Base

Abstract

The distribution of U(VI) from aqueous media into chloroform solution of N,N'-ethylenebis (4-butanoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine) (H 2 BuEtP) a Schiff base has been studied to determine the effect of buffer media, mineral acids, auxiliary complexing agents and 4-butanoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one (HBuP) on the distribution behaviour. A 1:1 interaction was observed between U(VI) and the ligand during the extraction process and one mole of hydrogen ion was found to have been displaced in the reaction process. The study shows that pH½ of the extraction of U(VI) shifted from 4.88 ± 0.10 to 2.14 ± 0.10 for CHCl 3 solutions of H 2 BuEtP and H 2 BuEtP-HBuP respectively. Extraction constants (Log K ex ) -1.68 ± 0.12 and -0.72 ± 0.13 were determined respectively from the studies, indicating that addition of HBuP made the extraction process more efficient. Species extracted were characterized as complexes with suggested formulae UO 2 (HBuEtP)X and UO 2 (HBuEtP)X.HBuP where X is an anion. Graphical analysis shows also that UO 2 (HBuEtP)X.HBuP could be extracted as UO 2 (BuP)X.(H 2 BuEtP), indicating a potential synthetic method for metal complex species with position isomers by liquid-liquid extraction technique. Studies of extraction from auxiliary complexing agents support the existence of species proposed above leading to enhanced extraction of U(VI) from X = NO 3 -, SO 4 2 , CH 3 COO -,SCN -, Cl -, I -and F -media. Percentage extraction of U(VI) from mineral acids suggests that U(VI) extraction tend to increase with decrease in acid strength.

Kinetic Studies on the Recovery of Pb2+and UO22+ from Aqueous Solutions into Chloroform Solution of N,N’-Ethylenebis(4-Butanoyl-2,4-Dihydro-5-Methyl-2-Phenyl-3H-Pyrazol-3-Oneimine) Schiff Base

“…The ligand N,N'-ethylenebis(4-butanoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine) (H 2 BuEtP) was synthesized by methods reported elsewhere [11,12,15]. The product was purified by recrystallization from aqueous ethanol and dried in air.…”

“…The extraction of UO 2 2+ ion and Pb 2+ ion from an aqueous phase using the tetra dentate ligand (H 2 BuEtP) in the organic phase has been treated as follows as reported by Godwin and Uzoukwu [11,12]. The extraction of metal ion M n+ from an aqueous phase using the ligand H 2 BuEtP in the organic phase can be treated as follows: (1) For which the extraction constant K ex1 is given as follows:…”

“…if it is assumed that a=1 then, integration of equation 5 (9) And from equation 9, `b` can be determined. The rate constants K f can be calculated from the intercept of plots of equations 8 and 9 when values for a, b, and c are known.…”

“…[7] has been used in the extraction of few metal complexes. This schiff base (H 2 BuEtP) which has a pKa of 6.6 + 0.1 was found to be an efficient ligand in the distribution of UO 2 2+ and Pb 2+ from aqueous pH solutions into chloroform solutions as reported by Godwin and Uzoukwu [11][12][13]. Optimal percentage extraction of above 98% was equally recorded for both metal ions and an efficient technique for separating both metals developed [13].…”

“…The continuous search for better and more efficient ligands has led to the synthesis and characterization of several ligands and Schiff bases [6][7] of which 1-phenyl-3-methyl-4-acyl-pyrazolone-5 and its derivatives have been studied and reported [8]. The role of these organic extractants in the recovery of several metals has equally been reported by several authors [9][10]. The schiff base N,N'-ethylenebis(4-butanoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine) (H 2 BuEtP) which was first synthesized and characterized by Uzoukwu, et, al.…”