K10-Montmorillonite as Support for a Cationic Manganese(III)-salen Complex

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Iwona Kuzniarska Biernacka (Author) Other; Clara Pereira (Author) Other; Ana P Carvalho (Author) Other; Joao Pires (Author) Other; Cristina Freire (Author) FCUP

Journal

Title: Journal of the Brazilian Chemical Society

Vol. 20

Pages: 1320-1326

ISSN: 0103-5053

Publisher: Sociedade Brasileira de Quimica

Indexing

ISI Web of Knowledge - 5 Citations

Scopus - 6 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-003-R3V

Abstract (EN): A commercial K10-montmorillonite was used as support for the immobilization of a cationic manganese(III)-salen complex. The catalytic behavior of the resulting material was tested in the enantioselective epoxidation of three different alkenes, viz.: styrene, alpha-methylstyrene and 6-cyano2,2- dimethylchromene, at 0 degrees C, using three different oxidant systems: m-chloroperoxybenzoic acid (m- CPBA) and N-methylmorpholine (NMO) as co-oxidant, iodosylbenzene (PhIO) and sodium hypochlorite. All samples, before and after the catalytic studies, were characterised by nitrogen adsorption at -196 degrees C, DRX, FTIR and chemical analysis, in order to evaluate the influence of the substrate/oxidant system on catalyst integrity. The catalytic results demonstrated a strong influence of the substrate and oxidant system on the enantiomeric excess (%ee) values. In some cases, these values were comparable to those in the corresponding homogeneous phase reactions. The results also highlighted the importance of optimizing the oxidant systems, since they may lead to the disruption of the complex from the support, and the consequent catalyst deactivation.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7