FADING OF ANIMOANTHRAQUINONE DISPERSE DYES BY NITROGEN OXIDE

The fading behavior and the initial products of 15 aminoanthraquinone disperse dyes exposed to dry nitrogen dioxide are investigated.Cellulose acetate film dyed or cast with the dyes, nylon 6 films dyed and the powdered dyes were subjected to the fading experiment, in which the specimens were placed in the gas atmosphere at 5mm Hg at 25°C.Results are as follows:1) At the initial stage of the gas fading of 11 dyes, the time dependent absorption spectra gives the isosbestic point indicative of the single reaction product9). 2) From the elemental analysis, paper chromatograph, IR spectra and colouration test, the primary products from 1, 4-diaminoanthraquinone and 1-methylaminoanthraquinone were identified as the 4-diazonium nitrate and the N-nitrosoamine, respectively. 3) In most cases, the fading was retarded with the dye concentration in the film. 4) The ease of the fading and the dye structure were related as in the previous studies4, 5).