Publication
Photochemistry of 4-chlorophenol on cellulose and silica
| dc.contributor.author | Silva, José P. da | |
| dc.contributor.author | Ferreira, Luís F. Vieira | |
| dc.contributor.author | Silva, Abílio M. da | |
| dc.contributor.author | Oliveira, A. S. | |
| dc.date.accessioned | 2015-06-22T14:13:52Z | |
| dc.date.available | 2015-06-22T14:13:52Z | |
| dc.date.issued | 2003 | |
| dc.description.abstract | The photochemistry of 4-chlorophenol (4-CP) was studied on silica and cellulose, using time-resolved diffuse reflectance techniques and product degradation analysis. The results have shown that the photochemistry of 4-CP depends on the support, on the concentration, and also on the sample preparation method. Transient absorption and photoproduct results can be understood by assuming the formation of the carbene 4-oxocyclohexa-2,5-dienylidene in both supports. On cellulose, at concentrations lower than 10 mumol g(-1), the carbene leads to the unsubstituted phenoxyl radical, and phenol is the main degradation product. At higher concentrations a new transient resulting from phenoxyl radicals coupling was also observed, and dihydroxybiphenyls are also formed. The reaction of the carbene with ground-state 4-CP was also detected through the formation of 5-chloro-2,4'-dihydroxybiphenyl. 4-Chlorophenoxyl radical and degradations products resulting from its coupling were also detected. Oxygen has little effect on the photochemistry of 4-CP on cellulose. On silica the transient benzoquinone O-oxide was formed in the presence of oxygen. Benzoquinone and hydroquinone are the main degradation products. In well-dried samples the formation of hydroquinone is reduced. At higher concentrations the same products as detected on cellulose were observed. 4-CP undergoes slow photochemical decomposition under solar radiation in both supports. The same main degradation products were observed in these conditions. | |
| dc.identifier.doi | https://dx.doi.org/10.1021/es026448c | |
| dc.identifier.issn | 0013-936X | |
| dc.identifier.uri | http://hdl.handle.net/10400.1/6580 | |
| dc.language.iso | eng | |
| dc.peerreviewed | yes | |
| dc.publisher | American Chemical Society | |
| dc.relation.isbasedon | P-000-ET2 | |
| dc.title | Photochemistry of 4-chlorophenol on cellulose and silica | |
| dc.type | journal article | |
| dspace.entity.type | Publication | |
| oaire.citation.endPage | 4803 | |
| oaire.citation.issue | 20 | |
| oaire.citation.startPage | 4798 | |
| oaire.citation.title | Environmental Science and Technology | |
| oaire.citation.volume | 37 | |
| person.familyName | Da Silva | |
| person.givenName | José Paulo | |
| person.identifier.ciencia-id | 3413-C4F4-73F7 | |
| person.identifier.orcid | 0000-0002-6458-7328 | |
| person.identifier.rid | A-4606-2008 | |
| person.identifier.scopus-author-id | 7201733236 | |
| rcaap.rights | restrictedAccess | |
| rcaap.type | article | |
| relation.isAuthorOfPublication | e2004fa2-a47d-44b0-b11c-fc95fe51cbf9 | |
| relation.isAuthorOfPublication.latestForDiscovery | e2004fa2-a47d-44b0-b11c-fc95fe51cbf9 |
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