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Synthesis and Study of Catalytic Activity of Iron (III)-bis(2-oxazolinyl) Methane complex by Urea Hydrogen Peroxide in Oxidation of Sulfides

Kazem, Nasrin | 2008

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39040 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Bagherzadeh, Mojtaba
  7. Abstract:
  8. Considerable effort has been directed in recent years towards the transition metal complex catalyzed oxidation of organic compounds. Herein the synthsis of the iron complex of bis(oxazoline) ligand as a novel catalyst is reported, and the catalytic activity of this complex in oxidation of sulfides is investigated. Bis(2-oxazolynil)methane as ligand is prepared by condensation of diethylmalonate with 2-aminoethanole in 1:2 molar ratio and finally corresponding complex is synthesized by the reaction between FeCl3.6H2O and Bis(2-Oxazolynil)methane in 1:1 molar ratio. The complex is characterized by using IR, UV-Vis, cyclic voltametery, conductometery and elemental analysis data. Moreover, catalytic activity of iron(III)-bis(Oxazoline) in oxidation of various sulfides using urea hydrogen peroxide (UHP) as oxidant is investigated. In order to obtain the best yield and selectivity, the effects of some factors including time, temperature, solvent, type of oxidant, axial ligand, the amount of oxidant, the amount of catalyst and the amount of substrate in oxidation of methylphenylsulfide are examined. Then, oxidation of various sulfides is studied under the obtained optimum conditions. The obtained results at room temperature and short reaction time (5 min) establish that this complex is an effective catalyst having a good selectivity toward sulfoxide as product, especially for dialkylsulfide (with 100% conversion). On the contrary diphenylsulfide and dibenzothiophen have the lowest conversion in this catalytic system (about 7%), substrates having benzylic hydrogen can be effectively oxidized to the corresponding products. Study of sulfoxide oxidation in this catalytic system reveals the catalytic system cannot oxidize sulfoxide to sulfone, and sulfone products are formed through a non-catalytic pathway. Effects of various nitrogen donor ligands such as imidazole upon methylphenylsulfide oxidation show that using axial ligands results in increasing of the sulfoxide selectivity (from 90% to 100%), but because the axial ligand is coordinated to the active site of the complex which makes the catalyst deactivate, the yield of the reaction was dramatically decreased
  9. Keywords:
  10. Urea-Hydrogen Peroxide ; Nitrogen Donor Ligand ; Bis Oxazoline ; Iron Complexes ; Axial Ligand ; Methylphenylsulfide

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