| Abstract: | The ‘catalytic fading’ of C.I. Acid Violet 4 in the presence of C.I. Acid Yellow 112 has been investigated in solution, on films and on fibres. Trace amounts of an impurity have been isolated from C.I. Acid Yellow 112. This impurity has been shown to fade C.I. Acid Violet 4 catalytically. Examination of the impurity and comparison of its properties with those of the sodio derivative of ethyl acetoacetate suggest that it is a β-ketonic acid derivative present in part as an enolic sodium salt. |
