Methoxystyrene and Anethole

While the above investigation was being completed, Goka and Sherrington published a study on the polymerisation of p-methoxystyrene by tropylium hexachloroan-timonate in methylene chloride. These authors showed unequivocally that the initiation reaction proceeded through the addition of the tropylium ion to the monomer double bond. They were able in fact to isolate and characterise this addition product. 

The kinetics of polymerisation were followed calorimetrically and attempts to follow the initiation reaction by NMR spectroscopy failed. The absence of appreciable termination was claimed on the basis that addition of a second monomer sample at the end of a polymerisation resulted in a second polymerisation with approximately the same propagation rate constant. The authors concluded that after a diort accel ation period one could equate the concentration of active species with that of the added initiator. However, the arguments they proposed to support this assumption are not convincing and the fact that the observed propagation rate constants were directly proportional to the initial monomer concentration shows on the contrary, as pointed out by Cotrel et al. 

---