Mechanism of Polymerization of 1, 3-Dioxolane Initiated by (C2H5)3 O+SbCl6 and SbCl5

The kinetics of polymerization of 1, 3-dioxolane (DiOX) initiated by (C₂H₅)₃O⁺SbCl₆ and SbCl₅ has been studied and the elementary stages of the process have been considered. The polymerization of DiOX by (C₂H₅)₃O⁺SbCl₆-is shown to proceed at a steady rate to high conversion. A constant concentration of active centers in the system is maintained due to the equal rates of decomposition of active centers and disproportionation. The nonsteady-state character of DiOX polymerization initiated by SbCl₅is associated with a relatively lower stability of the counter-ion SbCl₅ OR^? compared with SbCl₆. The initiation of DiOX polymerization by (C₂H₅)₃O⁺SbCl₆ proceeds without hydride-transfer reactions, and the concentration of active centers in the system is determined not by processes taking place in the initiation stage, but by the existence of a definite kind of equilibrium with the participation of active centers.