Studies on Aminoanthraquinone Compounds

The action of (a) near‐ultraviolet and visible radiation and (b) short‐wave ultraviolet radiation (mainly 253.7 nm) on cellulose Alms dyed with three acylaminoanthraquinone vat dyes has been studied. Photoreduction to the acid leuco derivative of the dye is observed only on exposure to 253.7‐nm radiation. One dye (l‐benzamidoanthraquinone) has also been studied in anaerobic ethanolic solution. On exposure of this solution to near‐ultraviolet and visible radiation, the dye is readily reduced to the anthrahydroquinone. Photo‐reduction occurs readily in ethanol but with considerable difficulty on cellulose. There seems to be no correlation between the ability of the vat dye to sensitise the photochemical degradation of cellulose textiles and its ability to be photoreduced on cellulose.