The overall rate constants of propagation (kp) in the bulk polymerization of te-trahydrofuran using allyl bromide (AB) or sebacoyl chloride (SC) and silver perchlo-rate as binary catalyst systems were determined to be 0.32 × 10-3 and 0.38 ×10-3 l mol-1. sec.-1

resp. The evidently low kp values were interpreted by the high nucleophilicity of counterion ClO4-. With increasing the amount of AgClO4 in the composition of AB-AgClO4 catalyst system (up to 51% molar excess)

the induction period of the initiation reaction decreases and the rate of polymerization increases

while the kp value would in-crease rather insignificantly.