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Titolo:
Epoxidation of crotyl alcohol using Ti-containing heterogeneous catalysts:Comments on the loss of Ti by leaching
Autore:
Davies, LJ; McMorn, P; Bethell, D; Page, PCB; King, F; Hancock, FE; Hutchings, GJ;
Indirizzi:
Cardiff Univ, Dept Chem, Cardiff CF10 3TB, S Glam, Wales Cardiff Univ Cardiff S Glam Wales CF10 3TB ardiff CF10 3TB, S Glam, Wales Univ Liverpool, Dept Chem, Leverhulme Ctr Innovat Catalysis, Liverpool L693BX, Merseyside, England Univ Liverpool Liverpool Merseyside England L69 3BX , Merseyside, England Loughborough Univ Technol, Dept Chem, Loughborough LE11 3TU, Leics, England Loughborough Univ Technol Loughborough Leics England LE11 3TU cs, England Synetix, Billingham TS23 1LB, Cleveland, England Synetix Billingham Cleveland England TS23 1LB S23 1LB, Cleveland, England
Titolo Testata:
JOURNAL OF CATALYSIS
fascicolo: 2, volume: 198, anno: 2001,
pagine: 319 - 327
SICI:
0021-9517(20010310)198:2<319:EOCAUT>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
SILICA MIXED OXIDES; LIQUID-PHASE OXIDATIONS; TITANIUM SILICALITE; MOLECULAR-SIEVES; HYDROGEN-PEROXIDE; HYDROTHERMAL STABILITY; CONTAINING MCM-41; ZEOLITE-BETA; METAL-IONS; UV-VIS;
Keywords:
epoxidation of allylic alcohols; heterogeneous epoxidation using TS-1; heterogeneous epoxidation using Ti-beta; heterogeneous epoxidation using Ti-MCM-41; heterogeneous epoxidation using Ti-xerogel; Ti-leaching;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Hutchings, GJ Cardiff Univ, Dept Chem, POB 912, Cardiff CF10 3TB, S Glam, Wales Cardiff Univ POB 912 Cardiff S Glam Wales CF10 3TB am, Wales
Citazione:
L.J. Davies et al., "Epoxidation of crotyl alcohol using Ti-containing heterogeneous catalysts:Comments on the loss of Ti by leaching", J CATALYSIS, 198(2), 2001, pp. 319-327

Abstract

The leaching of Ti from the redox molecular sieve TS-1 is compared and contrasted with Ti leaching from Ti-Al beta, Ti-MCM-41, and a Ti-xerogel underboth batch and continuous flow reaction conditions for the oxidation of crotyl alcohol with hydrogen peroxide. The product distributions for the catalysts are similar, with epoxide being formed initially and, subsequently, the secondary reaction products of the trial and ether dials. Ti leaching ismore pronounced under continuous flow conditions and the order of stability is TS-1 > Ti-Al beta > Ti-MCM-41 > Ti-xerogel, for both continuous flow and batch reaction conditions. TS-1 leaching is shown to be caused by the reaction of trial with TS-1 in the presence of hydrogen peroxide. A possible mechanism in which the triol byproduct chelates the Ti and breaks the Ti-O-Si framework bonds, leading in turn to the formation of a Ti species in solution, is proposed. The soluble Ti species is found to be an active homogeneous catalyst giving triol as the major product from crotyl alcohol. Under batch reaction conditions, it is possible that an equilibrium is established between the solution Ti species and Ti on the catalyst surface. This equilibrium is perturbed when continuous flow conditions are used, and this leads to increased Ti leaching. (C) 2001 academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 12:59:33