Process for the preparation of 2,4-diaryl-6-o-hydroxyphenyl-1,3,5-triazine derivatives in the presence of a protic acid catalyst

摘要

A process for preparing 2-(2,4-dihydroxyphenyl)-4.6-diaryl-s-triazines or related compounds in three steps starting with cyanuric halide or corresponding phenoxy or alkoxy substituted triazine is described. Step 1 involves the nucleophilic displacement of one or two leaving groups in the triazine with a phenolic moiety. Step 2 involves a Friedel-Crafts reaction using a Lewis acid catalyst (preferably aluminum chloride) to replace the remaining leaving group(s) with aryl groups such as xylyl. Finally, step 3 involves replacing the phenolic moiety with a phenol such as resorcinol using preferably a protic acid catalyst or a combination of a Lewis acid and a protic acid catalyst. Alternatively, step 3 may be performed alone, e.g. starting from materials from other processes, or leading directly to a tris-hydroxyphenyl-s-triazine. The s-triazines prepared are useful as UV absorbers for the stabilization of organic substrates against the adverse effects of actinic light.