2058-67-5Relevant articles and documents
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 4-Arylazo- and 4-Arylazoxy-N,N-dialkylaniline N-Oxides
Albini, Angelo,Fasani, Elisa,Moroni, Micaela,Pietra, Silvio
, p. 1439 - 1444 (2007/10/02)
The 4-aryl-N,N-dialkylaniline N-oxides (1a-c) decompose on u.v. irradiation in aprotic solvents, undergoing deoxygenation as well as intramolecular hydrogen abstraction, to give amides and dealkylated products.The latter process is more important for the diethyl derivative (1b) (photoCope elimination).Visible irradiation is ineffective.The 4-arylazoxy-N,N-dialkylaniline N-oxides (2a-d) undergo photochemical deoxygenation from the amino group (major process) as well as from the azo group.The mechanism of these photoprocesses is discussed in general and in relation to the possible involvement of these N-oxide derivatives in photofading of the related azo dyes.