- Studies on substituted aromatic diselenides as catalysts for selective alcohol oxidation using tert-butyl hydroperoxide
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We have investigated the Ph2Se2-catalysed oxidation of alcohols with tert-butyl hydroperoxide (TBHP) by using a variety of spectroscopic techniques and reaction calorimetry. We showed that the active oxidant is benzeneseleninic anhydride (BSA), formed by reaction of Ph 2Se2 with TBHP. The influence of aromatic substituents on the activity of a selection of nine aromatic diselenides involved in alcohol oxidations was studied. Calorimetric experiments showed that compounds that are activated more rapidly have higher initial activity in the catalytic oxidation of benzyl alcohol. An exception to this rule was observed when the diselenide contained a dimethylamino group in the ortho position, which can apparently compensate for its slow pre-activation by a special ortho effect. An aliphatic alcohol, 1-decanol was also used as a substrate. Besides diphenyl diselenide only three of the substituted diaryl diselenides studied showed reasonable activity after pre-activation with TBHP. Dimesityl diselenide displayed the highest activity and selectivity for the oxidation of 1-decanol. Specificity for a given aldehyde could be achieved by using an oxidant and substrate feed protocol. The oxidation steps from Ph2Se2 to benzeneseleninic anhydride, which is a gooddehydrogenation agent, have been elucidated by a combination of spectroscopic techniques, both in situ and ex situ. The oxidation potentials of derivatives of this anhydride have been investigated in the oxidation of 1-decanol.
- Van Der Toorn, John C.,Kemperman, Gerjan,Sheldon, Roger A.,Arends, Isabel W. C. E.
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scheme or table
p. 4345 - 4352
(2011/09/15)
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- Preparation of the First Organoselenium Peroxide, t-Butyl Benzeneperoxyseleninate
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t-Butyl benzeneperoxyseleninate, PhSe(O)OOBut, has been prepared by the reaction of t-butyl hydroperoxide with PhSe(O)OSe(O)Ph or PhS(O)OEt, and of sodium t-butyl peroxide with PhSe(O)Br.Formation of the less stable analogues p-MeC6H4Se(O)OOBut and BuSe(O)OOBut from t-butyl hydroperoxide and the corresponding seleninyl anhydrides has been confirmed by 13C n.m.r. spectroscopy.
- Bloodworth, A. J.,Lapham, David J.
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p. 471 - 474
(2007/10/02)
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