103809-61-6Relevant academic research and scientific papers
ELECTROCHEMICAL AND CHEMICAL OXIDATION OF SOME AZO DYES
Fasani, Elisa,Soldi, Teresa,Albini, Angelo,Pietra, Silvio
, p. 109 - 114 (2007/10/02)
The oxidation potential of representative azo dyes, viz. a series of N,N-dialkylaminoazo dyes 1 and of tautomeric azonaphthols (2 and 5) has been determined.Anodic oxidation and chemical oxidation have been carried out for some of the dyes.The results are rationalized as involving a single intermediate, the radical cation of the dyes, and its evolution along two main pathways, viz. a) deprotonation whenever possible (from the α position of the N-alkyl group in aminoazo dyes, leading ultimately to N-dealkylation; fromthe naphthols to eventually yield a C-C-coupled dimer) and b) heterolytic cleavage to an aryl radical and a diazonium cation, the latter trapped under favourable conditions to yield a bisazodye.
PHOTOCHEMICAL DECOMPOSITION OF 2,4-DINITRO-4'-DIMETHYLAMINOAZOBENZENE IN AERATED SOLUTION
Albini, Angelo,Fasani, Elisa,Pietra, Silvio
, p. 681 - 688 (2007/10/02)
The irradiation of various ketones in the presence of 2,4-dinitro-4'-dimethylaminoazobenzene (1) causes decomposition of the latter.The chemical process actually observed depends on the solvent and on the ketone structure.In benzene the dye (1) undergoes demethylation in the presence of 2,2-dimethoxy-2-phenylacetophenone (DMPA) and benzil.This is due to the reactions of benzoylperoxyl radicals formed from the ketone sensitizers in the presence of oxygen.Benzophenone and anthraquinone cause the same reaction, in this case through direct interaction of the n?* triplet with (1).In alcohols the situation is more varied, as with DMPA, benzil, and benzophenone in methanol, demethylation of (1) via the same mechanisms as above is observed, while with anthraquinone and acetone in methanol and with benzophenone in propan-2-ol, 2,4-dinitro-4'-dimethylamino-NNO-azoxybenzene, (4), is formed.The latter reaction is initiated by attack of ketyl radicals, formed in the primary photoreaction of the ketone with the solvent, onto (1).The relevance of this model for the fading of azo dyes under applicative conditions is discussed.
