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Titolo:
Enantioselective oxidation of sulfide to sulfoxide on Ti-containing mesoporous silica prepared by a template-ion exchange method
Autore:
Iwamoto, M; Tanaka, Y; Hirosumi, J; Kita, N; Triwahyono, S;
Indirizzi:
Tokyo Inst Technol, Chem Resources Lab, Midori Ku, Yokohama, Kanagawa 2268503, Japan Tokyo Inst Technol Yokohama Kanagawa Japan 2268503 anagawa 2268503, Japan
Titolo Testata:
MICROPOROUS AND MESOPOROUS MATERIALS
fascicolo: 1-3, volume: 48, anno: 2001,
pagine: 271 - 277
SICI:
1387-1811(20011101)48:1-3<271:EOOSTS>2.0.ZU;2-H
Fonte:
ISI
Lingua:
ENG
Soggetto:
TERT-BUTYL HYDROPEROXIDE; ASYMMETRIC OXIDATION; SELECTIVE OXIDATION; PLANTED MCM-41; CATALYSTS; EFFICIENT; ZEOLITES;
Keywords:
asymmetric oxidation; heterogeneous catalysis; MCM-41; sulfide; titanium ion;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
18
Recensione:
Indirizzi per estratti:
Indirizzo: Iwamoto, M Tokyo Inst Technol, Chem Resources Lab, Midori Ku, 4259 Nagatsuta, Yokohama, Kanagawa 2268503, Japan Tokyo Inst Technol 4259 Nagatsuta Yokohama Kanagawa Japan 2268503
Citazione:
M. Iwamoto et al., "Enantioselective oxidation of sulfide to sulfoxide on Ti-containing mesoporous silica prepared by a template-ion exchange method", MICROP M M, 48(1-3), 2001, pp. 271-277

Abstract

Ti-containing MCM-41 (Ti-M41) showed the highest catalytic activity for the asymmetric oxidation of sulfide with hydrogen peroxide in the presence ofoptically active tartaric acid among several metal-ion-containing MCM-41 samples. The chemical and optical yields of methyl 4-methylphenyl sulfoxidesreached 54% and 30% ee, respectively, in dichloromethane at a tartaric acid/titanium ratio of 2 at 273 K and 72 h reaction time. No titanium ion was dissolved into the CH2Cl2 solution from the Ti-M41 catalyst, concluding that the asymmetric oxidation indeed proceeded on the surface of the solid catalyst. The COOH and OH groups in optically active tartaric acid are both essential to the enantioselective oxidation. The degree of enantiomeric excess gradually increased with the reaction time. This was clarified to be due to the asymmetric induction in the sulfide oxidation and the kinetic resolution in the subsequent sulfoxides oxidation. With (R,R)-tartaric acid as a chiral modifier, the formation rate of (R)-sulfoxide was 1.5 times larger than that of (S)-isomer and the oxidation rate of (R)-sulfoxide to sulfone was 0.59 times that of (S)isomer. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 16/07/20 alle ore 05:51:58