| 摘要 |
Hologenated 2-(2-hydroxyphenyl)-2H-benzotriazoles of the formula <IMAGE> I, in which X is halogen, 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 corresponding o-nitroazo compound in the presence of a hydrogenation catalyst consisting of 0.1 to 3% of Pt on a support and of an organic amine.
|
