Methods for the preparation of tris-aryl-o-hydroxyphenyl-s-triazines

摘要

A process for preparing 2-(2,4-dihydroxyphenyl)-4.6-diaryl-s-triazines in three steps starting with cyanuric chloride is described. Step 1 involves the nucleophilic (basic) displacement of one chlorine atom with a phenolic moiety. Step 2 involves a Friedel-Crafts reaction using a Lewis acid catalyst (preferably aluminum chloride) to replace the remaining two chlorine atoms with aryl groups such as xylyl. Finally, step 3 involves replacing the phenolic moiety with resorcinol using either a Lewis acid or protic acid catalyst or combinations thereof. Some additional processes only peripherally related to the three-step process outlined above are also described for the preparation of various s-triazine compounds. The s-triazines prepared are useful as UV absorbers for the stabilization of organic substrates against the adverse effects of actinic light.