Isomerization polymerization of 2-oxazoline. III. Reactivities of unsisbstituted and 2-substittited 2-oxazoline monomers

Abstract

In the cationic isomerization polymerization of oxazoline with the initiator of methyl tosylate (MeOTs), the reactivities of 2-oxazoline (OXZ), 2-methyl-2-oxazoline (MeOXZ), and 2-phenyl-2-oxazoline (PhOXZ) were examined. The polymer yield in the same reaction time with the initiator of MeOTs decreased in the order of OXZ>MeOXZ>PhOXZ. The analysis of these relative reactivities was made on the basis of the principle that the rate of polymerization of the SN2 mechanism is controlled by the concentration of propagating species of oxazolinium, its ring-opening reactivity and the nucleophilic reactivity of monomer. (Remark: Graphics omitted.)Equimolar reactions of each monomer with MeOTs were followed by NMR spectrum, and the order of reaction rate was MeOXZ>OXZ>PhOXZ. Then the ring-opening reactivities of oxazolinium ions from three monomers were examined by equimolar reactions of N-methyl-oxazolinium tosylates of MeOXZ and PhOXZ with each monomers. The order of reactivity of oxazolinium salt was OXZ>PhOXZ>MeOXZ. From these results of the equimolar reactions, the over-all reactivities of polymerization of three oxazoline monomers were rationalized. © 1973, The Society of Polymer Science, Japan. All rights reserved.