Reaction Mechanism of Oxidation, Hydroxylation, and Epoxidation by Hypofluorous Acid: A Theoretical Study of Unusual H-Bond-Assisted Catalysis
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- 作者：Martin Srnec ; Milan Oná ; k ; Rudolf Zahradní ; k
- 刊名：Journal of Physical Chemistry A
- 出版年：2008
- 出版时间：April 24, 2008
- 年：2008
- 卷：112
- 期：16
- 页码：3631 - 3637
- 全文大小：322K
- 年卷期：v.112,no.16(April 24, 2008)
- ISSN：1520-5215
文摘
The oxidation of organic molecules by hypofluorous acid (HOF) was studied extensively and systematicallyby Rozen et al. Therefore, it seems appropriate to refer to the process as Rozen oxidation. An entire set ofmodel molecules was selected for quantum chemical investigation of the oxidation mechanism: a C=C doublebond in ethylene, sulfur and selenium in dimethyl derivatives, nitrogen and phosphorus in trimethyl derivatives,as well as methyl azides. In the gas phase, van der Waals complexes between HOF and the previously mentionedspecies easily are formed, but these complexes are reluctant to undergo oxidation. The addition of anotherHOF molecule connected with the formation of a cyclic complex (i.e., substrate and two molecules of HOF)seems to be decisive for the oxidation process. The attempt to substitute the second HOF molecule with H2Odemonstrated the superiority of HOF. Complexes of this kind decompose along the reaction path smoothly(i.e., with a low activation energy) to the respective oxidation product. A potential role of the hydroxyl cation(HO+) in the oxidation step is mentioned. Besides an oxidation product, one HOF molecule is released (anessential feature of catalysis), and furthermore, hydrogen fluoride is formed. It was suggested by Sertchooket al. (J. Phys. Chem. A 2006, 110, 8275) that the interaction between the substrate to be oxidized and HOFis catalytically influenced by the HF molecule. The mechanism suggested here is more feasible and, particularlyat the early stages of the oxidation process, decisive. Also, the role of acetonitrile, used as a solvent by Rozenet al., is discussed in terms of a continuum model. Moreover, passing from potential energies to Gibbs energiesis considered.