Silicate xerogels containing cobalt as heterogeneous catalysts for the side-chain oxidation of alkyl aromatic compounds with tert-butyl hydroperoxide
✍ Scribed by Marina Rogovin; Ronny Neumann
- Book ID
- 104424096
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 237 KB
- Volume
- 138
- Category
- Article
- ISSN
- 1381-1169
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✦ Synopsis
New transition metal substituted silicate xerogels, ML -SiO , have been prepared by the sol-gel technique and have n 2
been used as heterogeneous catalysts for the side-chain oxidation of alkyl arenes with anhydrous t-butylhydroperoxide. The cobalt substituted silicates were the most active and selective, for example, ethylbenzene was cleanly oxidized to acetophenone at 65% conversion and ) 99% selectivity. The metal salt precursor used was a key factor in determining the Ž . activity of the metallosilicate. Diffuse reflectance UV-vis and IR measurements indicated that when using Co OAc as 2 Ž . metal precursor, the acetate group was detached from the metal and Co II was tetrahedral and site substituted in the silicate Ž . network. Addition of the oxidant led to stabilization of a Co III oxidation state andror retention of the tetrahedral configuration.