Synthesis, Characterization and Solvent Extraction Studies of 3,5-bis[(2-hydroxy-benzylidene)-amino]-benzoic Acid and its Co(ii) and Ni(ii) Complexes
Synthesis, Characterization, and Solvent Extraction Studies of 3,5-bis[(2-hydroxy-benzylidene)-amino]-benzoic Acid and it’s Co(ii) and Ni(ii) Complexes.
ABSTRACT
3,5-Bis[(2-hydroxy-benzylidene)-amino]-benzoic acid (H2B) and its cobalt (II) and nickel (II) complexes were synthesized and characterized via electronic, IR, 1 H NMR, and 13C NMR. Job’s continuous variation method was used to determine the mole ratio for both metal complexes.
Solvent extraction studies were carried out on H2B in 5% DMF with its cobalt (II) and nickel (II) complexes using CHCl3 as an organic solvent; with variable condition effects of equilibrium time, buffer pH, mineral acids, salting-out agents, and complexing agents.
IR spectral study indicates coordination through (N2O2) azomethine and protonated hydroxyl groups. Job’s continuous variation method showed a metal to ligand ratio, 1:1, for both metal complexes of H2B. Cobalt (II) complex of H2B showed quantitative extraction in pH range 5 – 7,
while nickel (II) complex of H2B showed quantitative extraction in pH range 6 – 8. Nickel was successfully separated from cobalt by four-cycle extraction at 10-3 M HNO3 aqueous mixture of Ni(II) and Co (II) {10 µgcm-1 each} in 5% H2B/DMF using 0.05 M cyanide as a masking agent and CHCl3 as an organic solvent.
INTRODUCTION
Extraction is the transfer of a solute from one phase to another. Common reasons to carry out an extraction in chemistry are to isolate or concentrate the desired analyte or to separate it from species that would interfere in the analysis.
The most common cause is the extraction of an aqueous solution with an organic solvent that is immiscible and less dense than water; they form a separate phase that floats on top of the aqueous phase.
Solvent or liquid-liquid extraction is based on the principle that a solute can distribute itself in a certain ratio between two immiscible solvents, one of which is usually water and the other an organic solvent such as benzene, carbon tetrachloride, or chloroform. In certain cases, the solute can be more or less completely transferred into the organic phase.
The technique can be used for purposes of preparation, purification, enrichment, separation, and analysis, on all scales of working, from microanalysis to production processes.
In chemistry, solvent extraction has come to the forefront in recent years as a popular separation technique because of its elegance, simplicity, speed, and applicability to both tracer and macro amounts of metal ions.
The ability of a solute (inorganic or organic) to distribute itself between an aqueous solution and an immiscible organic solvent has long been applied to separation and purification of solutes either by extraction into the organic phase,
leaving undesirable substances in the aqueous phase; or by extraction of the undesirable substances into the organic phase, leaving the desirable solute in the aqueous phase.
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CSN Team.
