Synthesis, characterization and solvent extraction studies of 3,5-bis[(2-hydroxybenzylidene)- amino]-benzoic acid and its co(ii) and ni(ii) complexes

• Title page. . . . . . . . . . . i Declaration . . . . . . . . . . ii Certification . . . . . . . . . iii Dedication . . . . . . . . . . iv Acknowledgment . . . . . . . . . v Abstract . . . . . . . . . . vi Table of Contents . . . . . . . . . vii List of Tables . . . . . . . . . xi List of Figures . . . . . . . . . xii

Chapter ONE

INTRODUCTION

• 1.0General Introduction …………………………………………………. 1
• 1.1Background of Study…………………………………..…………… 2
• 1.2Scope of Study…………………………………………..…………… 3
• 1.3Significance of Study………………………………..……………… 4
• 1.8Aims and Objectives…………………………………………… 4

Chapter TWO

LITERATURE REVIEW

• 2.0Brief Chemistry of Metals under Study………,…………….. 6
• 2.1Cobalt ……………………………………………………… 6 2.
• 1.1Aqueous Chemistry of Cobalt …………………………………… 8 2.
• 1.2Oxidation States.…………………………… …………….. 8
• 2.2Nickel………… ……………………………………………. 13 2.
• 2.1Aqueous Chemistry of Nickel ………………………………. 15 viii 2.
• 2.2Oxidation States………………………………………………… 16 2.
• 2.3Uses of Nickel and its Compound……………………..………… 17 2.
• 2.4Nickel and Human Health……………………………………. 18
• 2.3Theoretical Fundamentals of Liquid-Liquid Extraction ……..….. 19 2.
• 3.1Distribution Law …………………………………………………. 20 2.
• 3.2Limitation of Nernst Distribution Law ………………………….. 22 2.
• 3.3Thermodynamic Partition Law Constant……………………… 24 2.
• 3.4Distribution Ratio ……………………………………………… 27
• 2.4Efficiency of Extraction ………………………………………… 28 2.
• 4.1Percentage Extraction ………………………………………….. 29 2.
• 4.2Separation Factor ……………………………………………… . 31
• 2.5Quantitative Treatment of Solvent Extraction Equilibrium …….. 33
• 2.6Extraction Methods in Solvent Extraction ……………………… 37 2.
• 6.1Batch Extraction ………………………………………………… 37 2.
• 6.2Continuous Extraction …………………………………………… 42 2.
• 6.3Discontinuous Countercurrent Extraction ……………………….. 43
• 2.7Classification of Inorganic Extraction System …………………. 45 2.
• 7.1Metal Chelate……………………………………………………. 46 2.
• 7.2Ion-association Complexes …………………………………….. . 53 2.
• 7.3Additive Complexes ……………………………………………. 54
• 2.8Factors that Influence Stability and Extractability of Metal Chelate Complexes……………………………………………. 57
• 2.9Brief Work on Solvent Extraction of Metals under Study… 62 ix
• 2.10Previous Work on 3,5-Bis[(2-Hydroxy-Benzylidene)-Amino]-Benzoic Acid……………………………………………………………. 66 2.
• 10.1Salens………………………………………………………… 68 2.10.
• 1.1Salen Ligand Synthesis…………………..………………….. 69

Chapter THREE

RESEARCH METHODOLOGY

• 3.0Experimental…………………………………………………… 73
• 3.1Equipments……………………………………………………….. 73
• 3.2Preparation of Metal Stock Solutions…………………………… 73
• 3.3Synthesis of 3,5-Bis[(2-Hydroxy-Benzylidene)-Amino]-Benzoic Acid ………………………………………………………………. 77
• 3.4Synthesis of Co(II) and Ni(II) Complexes of 3,5-Bis[(2-Hydroxy- Benzylidene)-Amino]-Benzoic Acid……………………….… 77
• 3.5Determination of the Composition of the Extracted Species….. 78
• 3.6Extraction Procedures ……………………………………………. 78 3.
• 6.1Extraction from Buffer Solution ………………………………… 79 3.
• 6.2Extraction from Acid Media……………………………………… 80 3.
• 6.3Extraction in Salting-out Agents………………………………….. 80 3.
• 6.4Extraction in Complexing Agents ………………………………… 81
• 3.7Measurement of Distribution Ratio……………………………….. 82
• 3.8Spectrophotometric Analysis of the Metal Ions…………………… 82
• 3.9Calibration Curve………………………………………………….. 83
• 3.10Separation Procedures……………………………………………. 84

Chapter FOUR

DATA PRESENTATION AND ANALYSIS

• 4.0Results and Discussion…………………………………………… 85
• 4.1Electronic Spectra………………………………………………… 85 x
• 4.2IR Spectra…………………………………………………………. 86
• 4.31H NMR Spectra …………………………………………………. 96
• 4.413C NMR Spectra ………………………………………………… 97
• 4.5Metal–Ligand Mole Ratio…………………………………………. 104
• 4.6Molecular Formula of the ligand and the Complexes …………. .. 104
• 4.7Solubility Data …………………………………………………… 109
• 4.8Dissociation and Protonation Constants of the Ligand ………… … 111
• 4.9Equilibration Time……………………………………………….. 115
• 4.10Effect of pH Buffer on Extraction of Co(II) and Ni(II) …………… 115
• 4.11Effect of Acidity …………………………………………………… 120
• 4.12Effect of Salting-out Agent on Extraction …………………………. 122
• 4.13Effect of Complexing Agents on Extraction ……………………. 125
• 4.14Degree of Metal Separation ………………………………………. 128
• 4.15Summary and Conclusion ………………………………………….. 128
• 4.16Recommendation………………………..………………………….. 130
• 4.17Contribution to Knowledge……….………………………………….. 131 References…………….……………………………………………. 132