Synthesis of benzyl chlorine-free poly(4-acetoxystyrene) via cationic polymerization followed by Friedel-Crafts alkylation

The linear benzyl chlorine-free poly(4-acetoxystyrene) (PSTO) with low polydispersity ( M w / M n = 1.3) is obtained through anisole quenching of the living polymerization of 4-acetoxystyrene initiated with the St–Cl/SnCl 4 /n-Bu 4 NBr system in CH 2 Cl 2 . The alkylation reaction rate increases with increasing anisole concentration and temperature. With a 4-fold excess of anisole over the initiator, end-chlorine groups are completely capped by anisole in 30 minutes at −15°C through adding extra SnCl 4 prior to the alkylation reaction. In addition, by using 2-methylanisole and 2,6-dimethylanisole as capping agents, it is verified that both para- and ortho-positions substitution of living PSTO cations to the anisole occur during alkylation reactions.