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Synthesis of Chloro Oxo (Tetraphenylporphyrinato) Vanadium(V) and Oxo (tetraphenylporphyrinato) Vanadium(IV) and Their Applications as a Catalyst for Oxidation of Sulfides and Epoxidation of Alkenes; Optimization of Reaction Condition by Response Surface Methodology (RSM)

Haghdoost, Mohammad Mehdi | 2010

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41376 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Bagherzadeh, Mojtaba
  7. Abstract:
  8. Petroleum contains a large variety of metal compounds with vanadium and nickel being the major metals. Some 6–34% of the total vanadium content is made up out of metallo-oxo-porphyrins, also referred to as petroporphyrins. Metalloporphyrins have long excited interest as oxidation and epoxidation catalysts. In the other hand the selective oxidation of sulfides to sulfoxides is of interest because of the importance of sulfoxides as synthetic intermediates in organic synthesis. A range of sulfides can be selectively oxidized to the corresponding sulfoxides in good yields using catalytic quantities of vanadyl complexes. Vanadium oxo tetraphenylporphyrin VO(TPP) catalyst is successfully applied in the selective oxidation of various sulfides to sulfoxides with urea hydrogen peroxide as oxidant under mild reaction conditions in excellent yield and selectivity. Several parameters have been tested for their impact on catalytic performance, measured by the turnover number (TON) and selectivity, using a surface response methodology for the optimization of the process. The maximum TON and selectivity obtained by this optimizing method were about 637 and 95%, respectively. Mechanism of sulfide oxidation with VO(TPP) catalyst also has been studied theorically using the DFT, B3LYP/DGTZVP basis set. The activation of dioxygen by metal complexes is a long sought goal in the field of catalysis. In this study, new vanadyl(V) tetraphenylporphyrin has been synthesized. The prepared complex has been characterized by CHN analysis, UV-Vis and NMR spectroscopy. Vanadyl(IV) and vanadyl(V) complex showed excellent catalytic activity and selectivity towards epoxidation cyclohexene using molecular oxygen. Catalytic activity and selectivity of vanadyl(V) complex using various oxidant compared with vanadyl(IV) complex. Using molecular oxygen, activity of vanadyl(V) complex is higher than vanadyl(IV) and main product is 2-cyclohexene1-ol. Structure of VO(TPP) and VO(TPP)Cl also has been determined with density functional theory, DGTZVP basis sets. Computational study showed some radical behavior for vanadyl(V) complex and this data is a good witness that proving radical mechanism for catalytic epoxidation by this complex
  9. Keywords:
  10. Vanadyl Complexes ; Density Functional Theory (DFT) ; Selective Oxidation ; Sulfide Oxidation ; Tetraphenyl Porphyrin ; Olefins Selective Oxidation

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