Abstract

Dioxiranes are used as reagents in a myriad of synthetically useful oxidations performed in aqueous medium. To extend such an approach also to substrates that are highly hydrophobic, we propose here the use of microemulsions based on the surfactant hexadecyltrimethylammonium hydrogen sulphate (CTAHS) because of its high stability against peroxide species. In this paper, we examine the dioxirane (isolated or generated in situ) reactivity in different CTAHS microemulsions. Yield and selectivity of the oxidation of b-methylstyrene by dimethyldioxirane (DDO) generate ‘‘in situ’’ and of laurolactam by isolated methyl(trifluorometyl)dioxirane (TFDO) were studied. For each microemulsion, the aggregate size and the localization of the components were determined by a combination of NMR and light scattering techniques. The hydrodynamic radius of the micelles is close to the length of the surfactant and this suggests they are spherical in shape. When acetone (the precursor of DDO) is present in the formulation, it partitions itself between the aqueous bulk and the micellar palisade so that the dioxirane eventually formed is readily available to oxidize substrates secluded in the micelle. Apolar substrates, confined within the micelles, are protected from uncontrolled oxidations, leading to an astonishing high selectivity of oxidation of laurolactam to 12-nitro-lauric acid by TFDO. This opens the way to an easy procedure (performed in water under mild conditions) to synthetize x-nitroacids.

Autore Pugliese

• Mele Giuseppe Agostino

Tutti gli autori

• C. Annese , L. D’Accolti , C. Fusco , G. Mele , G. Giorgio , G. Colafemmina , S. Murgia , G. Palazzo

Titolo volume/Rivista

JOURNAL OF COLLOID AND INTERFACE SCIENCE

Anno di pubblicazione

2013

ISSN

0021-9797

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

3

Ultimo Aggiornamento Citazioni

28/04/2018

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile