A CONTINUOUS PROCESS FOR THE SYNTHESIS OF AZO DYES INVOLVING IN-SITU GENERATION OF DIAZONIUM SALTS
The present disclosure provides a continuous process for the synthesis coupled compounds of diazonium salts including azo dyes involving in-situ generation of diazonium salts. It further discloses a set up to carry out the process for the synthesis of coupled compounds of diazonium salts.
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Paragraph 0053-0054
(2021/05/21)
Photochemical Decomposition of 4-Arylazo- and 4-Arylazoxy-N,N-dialkylaniline N-Oxides
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.