Direct Identification of the Initiation Products Initial Species

3 Direct Identification of the Initiation Products (Initial Species) 

Polymerization of THF initiated with fluorosulfonic acid (FSO3H) was studied by H-NMR in A singlet due to the acidic proton, exchangeable during poly- 

Oxygen atoms in macromolecules can also be protonated by any species 14a-14c  

These changes observed in H-NMR are illustrated in Fig. 1. The same figure describes tte chemical shift of the acidic proton as a function of the ratk) of concentrations [(C2Hs)2O]/[H0SO2CF3] for a non-polymerizable ether. This system qualitatively behaves in the same way as a syrtem with 1,3-dioxolane however, obviously, no upfield shift (due to polymerization and formation of HO—CH2-. .. groups) is observed for diethyl ether. 

At 25 °C, the rate of exchange of protons between components involved in Eq. (16) disallows the determination of their proportions although it follows from the dependence of the chemical shift on the starting ratio of 1,3-dioxolane to acid that the first equilibrium is almost completely shifted to the right-hand side. 

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