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Titolo:
TEMPO-derivatives as catalysts in the oxidation of primary alcohol groups in carbohydrates
Autore:
Bragd, FL; Besemer, AC; van Bekkum, H;
Indirizzi:
SCA Hyg Prod, NL-3704 AJ Zeist, Netherlands SCA Hyg Prod Zeist Netherlands NL-3704 AJ NL-3704 AJ Zeist, Netherlands Delft Univ Technol, Organ Chem & Catalysis Lab, NL-2628 BL Delft, Netherlands Delft Univ Technol Delft Netherlands NL-2628 BL 28 BL Delft, Netherlands
Titolo Testata:
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
fascicolo: 1-2, volume: 170, anno: 2001,
pagine: 35 - 42
SICI:
1381-1169(20010514)170:1-2<35:TACITO>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
MEDIATED OXIDATION; SELECTIVE OXIDATION; SODIUM-HYPOCHLORITE; OXOAMINIUM SALTS; POLYSACCHARIDES; STARCH; WATER;
Keywords:
starch; pullulan; methyl alpha-D-glucopyranoside; TEMPO-derivatives; oxidation of primary alcohol groups;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
23
Recensione:
Indirizzi per estratti:
Indirizzo: Bragd, FL SCA Hyg Prod, Utrechtseweg 48, NL-3704 AJ Zeist, Netherlands SCAHyg Prod Utrechtseweg 48 Zeist Netherlands NL-3704 AJ lands
Citazione:
F.L. Bragd et al., "TEMPO-derivatives as catalysts in the oxidation of primary alcohol groups in carbohydrates", J MOL CAT A, 170(1-2), 2001, pp. 35-42

Abstract

Primary hydroxyl groups in aqueous starch, pullulan and methyl alpha -D-glucopyranoside were oxidised to the corresponding carboxylic acid functionalities by TEMPO-(4-X)-derivatives using sodium hypochlorite as the primary oxidant. All the combinations of substrates and nitroxyl radicals resulted in stoichiometric conversions, and the selectivity for oxidation of primary hydroxyls was high. Some depolymerisation occurred throughout the oxidation, especially when 4-acetoxy and 4-mesyl-TEMPO were used. The pH window of the activity of the inexpensive 4-acetamido-TEMPO was found to be substantially lower from that of the other tested TEMPO-derivatives; thus allowing milder reaction conditions. At pH 8, the rate of oxidation was ca. two times higher when 4-acetamido-TEMPO was used compared to the other catalysts. (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 11/07/20 alle ore 11:07:08