CATIONIC POLYMERIZATION OF 2,2-DIMETHYL-1,3-DIOXOLE AND 2,2-DIPHENYL-1,3-DIOXOLE

Cationic polymerization of 2, 2-dimethyl-1, 3-dioxole (I) yields a polymer which contains both trans and cis monomer units as evidenced by NMR of the CH3 region (Ptrms ≃ 0.7). The 13C NMR spectrum also seems to support this configurational structure although cis (anti) and trans CH3 carbons could not be resolved, even at 67.8 MHz. The 2, 2-diphenyl-l, 3-dioxole (II), a new monomer, has been shown to be polymerized by BF3-Et2O at 25 °C, yielding a low molecular weight polymer. The 13C NMR data for the ipso carbon in poly-II suggests the presence of both cis and trans monomer units in the chain. Isomerization of the propagating cyclic carbenium ion appears to be a competing reaction in the polymerization of II. © 1979, American Chemical Society. All rights reserved.