EPR study on the mechanism of H2O2-based oxidation of alkylphenols over titanium single-site catalysts
| Autor: | Olga V. Zalomaeva, Irina D. Ivanchikova, Vladimir A. Rogov, Oxana A. Kholdeeva, Eugenii P. Talsi, Alexander B. Sorokin, Natalia Trukhan, Emil Roduner, Alexander Panchenko |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
010405 organic chemistry
Process Chemistry and Technology Inorganic chemistry chemistry.chemical_element 010402 general chemistry Photochemistry 01 natural sciences Catalysis 0104 chemical sciences Homolysis law.invention Titanium oxide chemistry.chemical_compound chemistry Transition metal law Phenol Hydroxyl radical Physical and Theoretical Chemistry Electron paramagnetic resonance Titanium |
| Zdroj: | Journal of Molecular Catalysis A: Chemical. 277:185-192 |
| ISSN: | 1381-1169 |
| DOI: | 10.1016/j.molcata.2007.07.047 |
| Popis: | The selective oxidation of 2,3,6-trimethylphenol (TMP) and 2-methyl-1-naphthol (MNL) with H2O2 catalyzed by titanium single-site catalysts, TiO2–SiO2 aerogel and mesostructured hydrothermally stable titanium-silicate, Ti-MMM-2, have been studied by means of EPR spectroscopic technique with spin traps. The formation of phenoxyl (naphthoxyl) and hydroxyl radical intermediates during the oxidation process have been detected using 3,5-dibromo-4-nitrosobenzene-sulfonic acid (DBNBS) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin traps, respectively. The character of the EPR spectra of the DBNBS adducts strongly depends on the nature of the organic substrate and the reaction temperature. A compilation of the EPR and by-product studies strongly supports a homolytic oxidation mechanism. Study by DR-UV–vis spectroscopy has confirmed the previously suggested chemical adsorption of phenol on the titanium center. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect