Primary Processes in the Reduction of Azo Dyes in Alcohols Studied by Pulse Radiolysis

Article abstract of DOI:10.1021/j100263a025

The Transient species produced in the reactions of solvated electrons and alcohol radicals with azobenzene and 4-(diethylamino)azobenzene have been studied in methanol and 2-propanol by spectrophotometric pulse radiolysis.One-electron reduction of the -N=N- bond is observed in both solvents by reaction of electrons (k=10¹⁰ M^1-s^1-).Only (CH3)2COH2 between the two α-hydroxyalkyl radicals, can give reduction of the azo bond.Both alcohol radicals undergo a very fast addition reaction with diethylaminoazobenzene (k=(4-5)X10⁹ M^1-s^1-).Subsequent formation of the hydrazyl radical is observed only on dissociation of the adduct of (CH3)2COH.The time evolution of the primary species formed has been followed.Association of hydrazyl radicals with the starting azo compounds has been detected.