PRODUCTION OF 2-PHENYLBENZOTRIAZOLES

PURPOSE:To produce high purity 2-phenylbenzotriazoles in a high yield, by adding an aq. soln. of an alkali metallic hydroxide and an alcoholic solvent to o-nitroazobenzenes represented by a specified formula to dissolve the compds. and by electrolytically reducing the resulting soln. CONSTITUTION:An alcoholic solvent such as ethanol an aq. soln. of an alkali metallic hydroxide such as NaOH are added to o-nitroazobenzenes represented by formula I or 2-phenylbenzotriazole-N-oxides represented by formula II to dissolve the compds. The resulting soln. is electrolytically reduced to produce 2-phenylbenzotriazoles represented by formula III. In the formulae I-III, R1 is H, Cl, 1-4C lower alkyl group or the like, R2 is H or Cl, R3 is H, Cl, 1-4C alkyl, 1-4C lower alkoxyl group or the like, R4 is H, Cl, hydroxy group or the like and R5 is H, 1-12C alkyl group or the like. The 2-phenylbenzotriazoles are obtd. with high safety in an energy saving manner without causing any problem on environmental pollution.