Trimethylsilyl trifluoromethanesulfonate as “initiator” of the cationic polymerization of styrenes

The cationic polymerization of styrene and p‐methylstyrene has been initiated in the presence of trimethylsilyl trifluoromethanesulfonate. In a dry system, no polymerization was observed. In wet systems, polymers were formed in agreement with earlier reports. In the presence of hindered pyridines, used as proton traps, polymerization has started after complete protonation of the hindered pyridines; at the same time hexamethyldisiloxane was formed. These results indicate that silyl triflates cannot react directly with styrenes, and that initiation proceeds via triflic acid which is formed by hydrolysis of silyl triflate.