Process for the preparation of benzotriazoles.

摘要

2-(2-Hydroxyphenyl)-2H-benzotriazoles of the formula (* CHEMICAL STRUCTURE *) I in which R is hydrogen, C1-C12alkyl or C1-C4alkoxy, R1 is hydrogen, C1-C12alkyl, C5-C6cycloalkyl, phenyl or phenyl-C1-C4alkyl and R2 is C1-C12alkyl, C5-C6cycloalkyl, phenyl, phenyl-C1-C4alkyl or a group -CnH2n-COOR3, in which n is 0 to 4 and R3 is hydrogen or C1-C12alkyl, can be prepared particularly advantageously by catalytic hydrogenation of a suitable o-nitroazo compound in the presence of a Pt, Pd, Pt/Pd or Rh hydrogenation catalyst and an alkylenediamine or an acyclic or cyclic polyalkylene polyamine in a halogenated or nonhalogenated aromatic hydrocarbon as solvent.