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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Photooxidative degradation of QTX (a thioxanthone derivative)

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Author(s):
Neumann, Miguel G. [1] ; Schmitt, Carla C. [1] ; Poli, Alessandra L. [1] ; Netto-Ferreira, Jose Carlos [2] ; Osajima, Josy A. [1]
Total Authors: 5
Affiliation:
[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
Total Affiliations: 2
Document type: Journal article
Source: Journal of the Brazilian Chemical Society; v. 22, n. 2, p. 217-222, FEB 2011.
Web of Science Citations: 0
Abstract

The photooxidative degradation of QTX (2-hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N,N-trimethyl-1-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 due to photoproducts 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)

FAPESP's process: 05/03692-4 - Contributions to the study of the photostability of dyes in polymers
Grantee:Carla Cristina Schmitt Cavalheiro
Support Opportunities: Regular Research Grants
FAPESP's process: 07/08515-9 - Photoinitiated polymerization: elemental reactions and overall
Grantee:Miguel Guillermo Neumann
Support Opportunities: Regular Research Grants