CRIS Current Research Information System
IRIS è la soluzione IT che facilita la raccolta e la gestione dei dati relativi alle attività e ai prodotti della ricerca. Fornisce a ricercatori, amministratori e valutatori gli strumenti per monitorare i risultati della ricerca, aumentarne la visibilità e allocare in modo efficace le risorse disponibili.
EnglishThis report deals with the results of a study on the oxidation of cyclohexanone to adipic acid with air, catalysed by Keggin-type polyoxometalates of composition H3+xPMo12−xVxO40 (x = 1 and 2), which was carried out in a semi-continuous stirred-tank reactor. It was found that when conducted in the presence of a water-only solvent, the reaction proceeds with a redox mechanism, in which the step of reoxidation of the reduced POM by oxygen is rate limiting. When, however, the reaction was carried out with an acetic acid co-solvent, a radical-chain autoxidation mechanism prevailed, especially when very low amounts of catalyst were used. Autoxidation overlapped with the redox mechanism when the catalyst-to-cyclohexanone ratio was increased. Moreover, the composition of the polyoxometalate, that is, the number of V atoms per Keggin unit, affected the relative importance of the two mechanisms. The selectivity to adipic acid achieved was a function of the reaction mechanism, but also was affected by cyclohexanone conversion, due to the presence of a complex reaction network.
| Titolo: | Evidence for the presence of alternative mechanisms in the oxidation of cyclohexanone to adipic acid with oxygen, catalysed by Keggin polyoxometalates | |
| Autore/i: | CAVANI, FABRIZIO; FERRONI, LAURA; FRATTINI, ALESSANDRA; C. Lucarelli; A. Mazzini; RAABOVÁ, KATERINA; S. Alini; P. Accorinti; P. Babini | |
| Autore/i Unibo: | ||
| Anno: | 2011 | |
| Rivista: | ||
| Digital Object Identifier (DOI): | http://dx.doi.org/10.1016/j.apcata.2010.04.032 | |
| Abstract: | This report deals with the results of a study on the oxidation of cyclohexanone to adipic acid with air, catalysed by Keggin-type polyoxometalates of composition H3+xPMo12−xVxO40 (x = 1 and 2), which was carried out in a semi-continuous stirred-tank reactor. It was found that when conducted in the presence of a water-only solvent, the reaction proceeds with a redox mechanism, in which the step of reoxidation of the reduced POM by oxygen is rate limiting. When, however, the reaction was carried out with an acetic acid co-solvent, a radical-chain autoxidation mechanism prevailed, especially when very low amounts of catalyst were used. Autoxidation overlapped with the redox mechanism when the catalyst-to-cyclohexanone ratio was increased. Moreover, the composition of the polyoxometalate, that is, the number of V atoms per Keggin unit, affected the relative importance of the two mechanisms. The selectivity to adipic acid achieved was a function of the reaction mechanism, but also was affected by cyclohexanone conversion, due to the presence of a complex reaction network. | |
| Data prodotto definitivo in UGOV: | 2013-06-16 18:06:00 | |
| Data stato definitivo: | 2016-01-01T20:12:13Z | |
| Appare nelle tipologie: | 1.01 Articolo in rivista |
File in questo prodotto:
http://hdl.handle.net/11585/112814
Copyright © 2022