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Titolo:
MANGANESE-PORPHYRINS AND MANGANESE-AZAPORPHYRINS AS CATALYSTS IN ALKENE EPOXIDATIONS WITH PERACETIC-ACID .2. KINETICS AND MECHANISM
Autore:
BANFI S; CAVAZZINI M; COPPA F; BARKANOVA SV; KALIYA OL;
Indirizzi:
CNR,CTR STUDIO SINTESI & STEREOCHIM SPECIALI SISTEMI,VIA C GOLGI 19 I-20135 MILAN ITALY ORGAN INTERMEDIATES & DYES INST MOSCOW 103787 RUSSIA
Titolo Testata:
Perkin transactions. 2
fascicolo: 8, , anno: 1997,
pagine: 1577 - 1583
SICI:
0300-9580(1997):8<1577:MAMACI>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
O BOND-CLEAVAGE; IRON(III) PORPHYRINS; OLEFIN EPOXIDATION; OXYGEN ACTIVATION; OXIDATION; METALLOPORPHYRINS; CYTOCHROME-P-450; SUBSTITUENTS; SELECTIVITY; IRON;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
36
Recensione:
Indirizzi per estratti:
Citazione:
S. Banfi et al., "MANGANESE-PORPHYRINS AND MANGANESE-AZAPORPHYRINS AS CATALYSTS IN ALKENE EPOXIDATIONS WITH PERACETIC-ACID .2. KINETICS AND MECHANISM", Perkin transactions. 2, (8), 1997, pp. 1577-1583

Abstract

cis-Stilbene (cSt) and I,1-diphenyl-2-picrylhydrazine (DPPH) were used as substrates for kinetic investigations of the catalytic system based on Mn-III-porphyrins and peracetic acid in CH3CN. Catalysts employed were tetra-(2,6-dichlorophenyl)-porphyrinatomanganese chloride (TDCPPMnCl) 5, octanltrophthalocyaninatomanganese chloride (NO2PcMnCl) 6 and tetra(tert-butyl)-tetraazaporphyrinatomanganese chloride (TAPMnCl) 7. It was found that for all these catalysts the first step of the reaction mechanism is the formation of an adduct 'A' between the catalyst and AcOOH in a reversible way (k(1)/k(-1)), followed by an irreversible stage (k(2)) for the formation of Mn-V-oxo species. The oxidative capability of the adduct 'A' was found to be dependent on the electronicstructure of the catalyst, while the reactivity of Mn-oxo species is only slightly influenced by catalyst structure, The formation of the high-valent Mn-oxo species is the rate-determining step of alkene epoxidations as demonstrated by the same k, value obtained with catalyst 6 in the epoxidation of cSt and trans-stilbene (tSt), Catalyst stabilitywas found to be dependent on solvent polarity, CH3CN being the best reaction medium.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 16:19:44