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Study on the Influence of the Functional Groups of Schiff Base Complexes on Oxygen Adsorption and Catalysis

Roshdi Ferdosi, Shayesteh | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41839 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Ghanbari, Bahram
  7. Abstract:
  8. Co(salen)-type complexes: Co(salen), Co(salophen), Co(3,5-Brsalen), Co(Clsalen), Co(3-OMe,5-Brsalen), Co(saltmen), Co(Brsalen), Co(OMesalen) were shown to be efficient catalysts for oxidizing cumene to cumyl alcohol, methylstyrene and acetophenone. The mixture was characterized by 1H NMR and GC-Mass spectroscopy. Product s efficiency and turnover number of catalysists were determined. Proposal of the mechanism provides a rationale for the influence of ligand substitutions on the reaction. A series of experiments are reported to provide strong support for a mechanistic scheme that involves reaction of coordinated dioxygen. On the basis of these observations, the coordination of O2 to this cobalt(II) complexes enhanced the ability of the dioxygen to abstract hydrogen atoms from cumene to initiate the reaction. LCoIII-OOcum complexes proposed as an intermediate and this is indicated by the extent of cumene oxidation by discrete novel CoIII(salen)OOcum complex which was synthtized and applied separately in the mechanism mixture. On the basis of the proposed mechanism, L, afford ROO. and RO. radicals upon mild heating in solution. This fact allows oxidation of hydrocarbons by these complexes under mild conditions. The formation of acetophenone, with one carbon less than cumene, is suggested to occur via a multistep pathway involving decarbonylation of the acyl radical from 2-phenylpropanal. An alternative mechanism distinctively involves Beta-scission of cumyloxyl radical
  9. Keywords:
  10. Cobalt Salen ; Cumene Oxidation ; Alkyl Peroxy Complex

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