NEW MATERIAL:A benzylpyridinium salt expressed by formula I (R1, R2 and R3 are H, halogen, alkyl, alkoxy, nitro, amino or hydroxy; R4 is halogen or alkanoyl; M is As, Sb, B or P; X is halogen; n is 4 when M is B and 6 when M is others). EXAMPLE:1-(4-Methoxybenzyl)-2-chloropyridinium hexafluoroantimonate. USE:A thermal latent cationic polymerization initiator, nearly inactive at ordinary temperature but capable of exhibiting function as an initiator only by heating. For example, the above-mentioned salt is suitable for applications utilizing thermal latency, such as a curing agent for one-pack type epoxy resins. PREPARATION:A pyridine expressed by formula II is quaternized with a substituted benzyl halide expressed by formula III and halide anions of the formed pyridinium halide are exchanged with ions expressed by formula IV to afford the benzylpyridinium salt expressed by formula I.
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