Enhanced Activity and Selectivity in Cyclohexane Autoxidation by Inert H-Bond Acceptor Catalysts
✍ Scribed by Ive Hermans; Jozef Peeters; Pierre A. Jacobs
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 142 KB
- Volume
- 7
- Category
- Article
- ISSN
- 1439-4235
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✦ Synopsis
Abstract
Herein, we demonstrate that the chain‐initiating dissociation of cyclohexyl hydroperoxide, CyOOH, is substantially accelerated by H‐bond acceptors (e.g. Teflon), which assist OO bond breaking by stabilising the leaving ^⋅^OH radical. This is a completely new approach to boost the chain‐propagating radical concentration. Indeed, up to now, literature has remained focussed on transition metal catalysis. In addition to this initiation effect, we demonstrate how inert perfluorinated compounds are also able to steer the selectivity at the molecular level, by promoting the conversion of the intermediate cyclohexyl hydroperoxide to the most desired end‐product, cyclohexanone. This effect is explained by an enhanced, H‐bond‐assisted, hydroperoxide propagation. This hitherto overlooked hydroperoxide propagation was recently presented by us as the dominant cyclohexanone and cyclohexanol source. We herein thus confirm our previously reported autoxidation scheme, and illustrate its usefulness as a solid basis for designing new catalytic systems.