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Proton chemical polarisation, autocatalysis and frontal kinetics of the oxidation of dialkylsulphides with nitric acid
Author(s) -
Rudakov E. S.,
Mastikhin V. M.,
Popov S. G.,
Rudakova R. I.
Publication year - 1973
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270050708
Subject(s) - autocatalysis , chemistry , disproportionation , nitric acid , catalysis , kinetics , radical , proton , cidnp , inorganic chemistry , photochemistry , chemical kinetics , medicinal chemistry , organic chemistry , physics , quantum mechanics
The oxidation of dimethyl sulphide to dimethylsulphoxide with nitric acid displays CIDNP effects of protons and the phenomenon of frontal kinetics. The process is autocatalytic, with N 2 O 4 as the catalyst and the primary oxidant of sulphide. In the presence of the inhibitor (methylmercaptan) the frontal reaction takes place: in purified samples—the usual volume reaction. The interaction of ethyl, n ‐propyl and n ‐butyl sulphides with NO 2 is accompanied by integral polarisation of the α‐CH 2 ‐protons. In all the cases sulphide is negatively polarised and sulphoxide positively polarised. The reaction mechanism proposed includes the formation of a radical pair during the interaction of sulphide with N 2 O 4 . Disproportionation of the radical pair leads to the formation of polarised sulphoxide and the decay results in re‐generation of sulphide. The rate of oxidation of sulphide during the volume reaction is proportional to the product polarisation.