Thioxanthone prepn. from O,O'-di:halo:benzophenone - by reacting with alkali(ne earth) metal sulphide; used as initiators for photopolymerisable compsns.

摘要

Thioxanthones of formula (I) are prepd. by reacting O,O1 dihalogenobenzophenone of formula (I') with a metal (hydrogen)sulphide, pref. an alkali(ne earth)metal sulphide, esp. Na2S. (where R1 and R2 are H, halogen, 1-4C alkyl or 1-12C alkoxy m and n are 0-3 R3 and R4 are indep. 1-4C alkyl. Thioxanthones obtd. by this process are also claimed, esp. 2-chlorothioxanthone. Reaction is at 20-250 degrees (75-105)C in a pref. polar org. solvent. (I) are used for coating and as printing inks, the compsns. curing by inadiating with light of wave lengths 250-400 mm.