Photooxidative Degradation of QTX (a Thioxanthone Derivative)

Autor(es)

Neumann, Miguel G. ^[1] ; Schmitt, Carla C. ^[1] ; Poli, Alessandra L. ^[1] ; Netto-Ferreira, Jose Carlos ^[2] ; Osajima, Josy A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Fed Rural Rio de Janeiro, Dept Quim, Inst Ciencias Exatas, BR-23851970 Seropedica, RJ - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of the Brazilian Chemical Society; v. 22, n. 2, p. 217-222, FEB 2011.
• Citações Web of Science: 0

Resumo

The photooxidative degradation of QTX (2-hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl -l-propanium chloride) has been investigated and photoproducts from QTX degradation in aqueous solution were characterized using HPLC/ESI-MS. The photooxidation of the dye was monitored by electronic absorption spectroscopy. The spectrum of the dye shows bands at 273 and 402 nm. During irradiation, the intensity of these bands decreases together with the appearance of a band at 310-340 nm, typical of oxidized QTX. The chromatograms show the presence of new peaks clue to photoproclucts of QTX degradation that were identified by mass spectroscopy. The peaks at m/z 388, 420 and 270 were attributed to photoproducts, whereas the peak at m/z 372 is due to QTX. The peak at m/z 388 corresponds to the formation of a sulfoxide group and that at m/z 420 suggested the formation of a sulfone with a hydroxyl on the methyl group. The peak at m/z 270 suggests that oxygen reacts with QTX abstracting a hydrogen atom from the carbon bonded the hydroxyl, together with the release of the amino group. (AU)

• Processo FAPESP: 05/03692-4 - Contribuições aos estudos da fotoestabilidade de corantes em polímeros
• Beneficiário: Carla Cristina Schmitt Cavalheiro
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 07/08515-9 - Polimerização fotoiniciada: reações elementares e processos globais
• Beneficiário: Miguel Guillermo Neumann
• Linha de fomento: Auxílio à Pesquisa - Regular