5 - Chlorine - 2 - (2 '- hydroxy - 5' - tert-octylphenyl) - benzotriazole, polypropylenes containing it, and a method for the production of hydroxyl aryl benzotriazoles and their n - oxides

摘要

Catalytic hydrogenation of o-nitrophenylazohydroxyaryls in an alkaline medium yields hydroxyarylbenzotriazoles; under mild conditions an N-oxide is formed. E.g., 6-tert-butyl-2-(5'-chloro-2'-nitrohenylazo)-p- cresol is hydrogenated to 5-chloro-2-(3'-tert-butyl-2'-hydroxy-5'- methylphenyl) benzotriazole, using platinum sulfide catalyst in the presence of sodium hydroxide: ##SPC1##PPIn this case A in the starting chemical is 5-chloro, n is 1, Ar is phenyl nucleus, m is 2, one B is 6- tert-butyl and the other B is 4-methyl; in the product x is zero. Chemicals useful for various purposes, including the stabilization of polymeric materials (e.g., polypropylene, polyvinyl chloride) against light, may be made by the process.