1H-NMR of the esterification of syndiotactic poly(methacrylic acid) with carbodiimides—II. Esterification with benzylalcohol and trifluoroethanol

Abstract

The partial esterification of syndiotactic poly(methacrylic acid) with benzyl alcohol or trifluoroethanol and dicyclohexylcarbodiimide as a condensing agent has been studied, evaluating triad and pentad probabilities by 1H-NMR. The mechanism of this esterification leads to a tendency toward alternation for esterified and unesterified monomer units along the chain and to a limiting conversion. Only a moderate approximation of triad and pentad probabilities by conditional probabilities of first and second order was possible. The esterification of poly(methacrylic acid) with trifluoroethanol has been carried out also in conc H 2SO 4 and leads to a random distribution of monomer units.