Fading of Colour Photographic Dyes III-Isolation and Identification of Reductive Fading Products of 1-phenyl-3-methyl-4-aza-(p-diethylaminophenyl)-2-pyrazoline-4,5-dione by Bisulphite

In order to confirm the fading reaction mechanisms of magenta azomethine dyes in the presence of bisulphite and thiosulphate ions, a faded material was synthesized from viewpoint of organic chemistry. Then identification was made on the compound by means of elemental and spectroscopic analyses. The colourless compound prepared was proven to be an adduct of dye and bisulphite ion hydrated with one molecule of water, and to be identical with the faded product observed in situ by Miyagawa et al according to spectroscopic analysis. Kinetic and thermodynamic parameters of the formation of the colourless compound are also provided in this paper to confirm the above result.