Influence of the alkyl group of triflate esters on their initiation ability for the cationic ring-opening polymerization of tetrahydrofuran

Esters of trifluoromethane sulfonic acid have been synthesized by reaction of different alcohols with triflic anhydride and used in situ as initiators for the polymerization of tetrahydrofuran. Kinetic studies of the polymeri zation showed that allyl triflate has the highest reactivity and that an in crease of the alkyl chain length of the initiator leads to a significant de crease of the initiation rate. "Non-linear" triflate ester such as isobutyl triflate leads to incomplete initiation. It was impossible to synthesize q uantitatively the triflate from tert-butyl alcohol due to spontaneous elimi nation leading to isobutylene.