Mechanistic Insights into Oxidation of 2-Methyl-1-naphthol with Dioxygen: Autoxidation or a Spin-Forbidden Reaction? Full article
| Journal |
The Journal of Physical Chemistry B
ISSN: 1520-6106 , E-ISSN: 1520-5207 |
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| Output data | Year: 2011, Volume: 115, Number: 42, Pages: 11971-11983 Pages count : 13 DOI: 10.1021/jp2055975 | ||||
| Tags | Catalyst selectivity; Dimers; Electron transitions; Free radical reactions; Ketones; Molecular oxygen; Phenols; Reaction rates | ||||
| Authors |
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| Affiliations |
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Funding (3)
| 1 | Russian Foundation for Basic Research | 05-03-34760 |
| 2 | French National Centre for Scientific Research | |
| 3 | French Embassy in Moscow |
Abstract:
Oxidation of 2-methyl-1-naphthol (MNL) with molecular oxygen proceeds efficiently under mild reaction conditions (3 atm O2, 60–80 °C) in the absence of any catalyst or sensitizer and produces 2-methyl-1,4-naphthoquinone (MNQ, menadione, or vitamin K3) with selectivity up to 80% in nonpolar solvents. 1H NMR and 1H,1H-COSY studies revealed the formation of 2-methyl-4-hydroperoxynaphthalene-1(4H)-one (HP) during the reaction course. Several mechanistic hypotheses, including conventional radical autoxidation, electron transfer mechanisms, photooxygenation, and thermal intersystem crossing (ISC), have been evaluated using spectroscopic, mass-spectrometric, spin-trapping, 18O2 labeling, kinetic, and computational techniques. Several facts collectively implicate that ISC contributes significantly into MNL oxidation with O2 at elevated pressure: (i) the reaction rate is unaffected by light; (ii) C–C-coupling dimers are practically absent; (iii) the reaction is first order in both MNL and O2; (iv) the observed activation parameters (ΔH‡ = 8.1 kcal mol–1 and ΔS‡ = −50 eu) are similar to those found for the spin-forbidden oxidation of helianthrene with 3O2 (Seip, M.; Brauer, H.-D. J. Am. Chem. Soc.1992, 114, 4486); and (v) the external heavy atom effect (2-fold increase of the reaction rate in iodobenzene) points to spin inversion in the rate-limiting step.
Cite:
Kholdeeva O.A.
, Ivanchikova I.D.
, Zalomaeva O.V.
, Sorokin A.B.
, Skobelev I.Y.
, Talzi E.P.
Mechanistic Insights into Oxidation of 2-Methyl-1-naphthol with Dioxygen: Autoxidation or a Spin-Forbidden Reaction?
The Journal of Physical Chemistry B. 2011. V.115. N42. P.11971-11983. DOI: 10.1021/jp2055975 WOS Scopus РИНЦ ANCAN PMID OpenAlex
Mechanistic Insights into Oxidation of 2-Methyl-1-naphthol with Dioxygen: Autoxidation or a Spin-Forbidden Reaction?
The Journal of Physical Chemistry B. 2011. V.115. N42. P.11971-11983. DOI: 10.1021/jp2055975 WOS Scopus РИНЦ ANCAN PMID OpenAlex
Dates:
| Submitted: | Dec 9, 2010 |
| Accepted: | Aug 9, 2011 |
| Published online: | Sep 30, 2011 |
| Published print: | Oct 27, 2011 |
Identifiers:
| Web of science: | WOS:000296204800001 |
| Scopus: | 2-s2.0-80054917881 |
| Elibrary: | 18010862 |
| Chemical Abstracts: | 2011:1249489 |
| Chemical Abstracts (print): | 155:535660 |
| PMID: | 21913639 |
| OpenAlex: | W2018013118 |