TRANSFORMATION OF DYES AND RELATED-COMPOUNDS IN ANOXIC SEDIMENT - KINETICS AND PRODUCTS

The reactions of several azo, anthraquinone, and quinoline dyes were studied in settled sediments. Several 1-substituted anthraquinones were lost from sediment with half-lives less than 10 days. For monosubstituted 1-amino and 1-methylamino (Disperse Red 9) compounds, the most stable product is the intramolecularly hydrogen-bonded anthrone. The 1,4-diaminoanthraquinone (Disperse Violet 1) and 1,4-diamino-2-methoxyanthraquinone (Disperse Red 11) were lost without formation of detectable products except for a demethylation product of the latter. Both the anthrone from Disperse Red 9 and the demethylation product of Disperse Red 11 reacted with half-lives of a few months, but other major products were not detected. An azo dye (Solvent Red 1) and a quinoline dye (Solvent Yellow 33) were transformed with half-lives of a few days and months, respectively. The azo dye reacted by reductive cleavage of the azo bond.