Styrene cyclic oligomers formation

The formation of cyclic dimer (2-10 % yield) in the cationic polymerization of styrene oxide was reported by different authors 25 27). More recently, Yamashita studied the catonic oligomerization of styrene oxide in the presence of various Lewis and protic acids as initiators (SnCl4, BF3 0(C2H5)2, HOS02CF,) and found a 100 o conversion to cyclic oligomers with n = 2-5 28). 

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