The title compounds, both disazo dyes, were found to undergo photoisomerism in dimethylphthalate solution and in films cast from a mixture of dye and cellulose acetate. Light-induced isomerism did not occur, however, in PET film that had been extruded, oriented, and dyed with the same two colorants. The prolonged irradiation of disperse yellow 23 in either solution or a polymer matrix produced azobenzene and some mono-substituted azobenzenes. Disperse orange 29 underwent photodegradation to produce a mixture of disubstituted monoazobenzenes, a partially reduced disazo- benzene, and para-nitroaniline.
References
1.
Freeman, H.S. , and McIntosh, S.A., Photolytic Properties of ortho- Substituted 4-[N,N-bis(β-Hydroxyethyl)amino]azobenzenes in Polymer Substrates . Textile Res. J.59 (6), 343-349 (1989).
2.
Hirashima, T. , Manabe, O., and Hiyama, H., Photodecomposition Products of Congo Red , Kogyo Kazaku Zasshi70, 1533 (1967).
3.
McIntosh, S.A. , Freeman, H.S., and Singh, P., X-Ray Crystal Structure of the Dyes 2-Nitro-4'-[N,N-bis-(β-Hydroxyethyl)amino]azobenzene and 2-Cyano-4'-[N,N-bis(β-Hydroxyethyl)amino]azobenzene, Textile Res. J.59(7), 389 (1989).
4.
Naumova, I.A. , Zaitsev, B.E., and Belen'hii , L.I., Lightfastness of Azo Dyes in Solution and on Polymer Films, Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.13(9), 1340 (1970 ).
5.
Still, W.C., Kahn, M., and Mitra, A., Rapid Chromatographic Technique for Preparative Separations with Moderate Resolution, J. Org. Chem.43, 2923-2925 (1978),
6.
Weast, R. C., and Astle, M. J., Eds., in "Handbook of Chemistry and Physics ," 62nd ed., CRC Press, Inc. , Boca Raton, FL, 1981- 1982, p. C-114, no. 1467.
