Trends in Kinetic Behavior during Ester-Ester Exchange Reactions in Polyesters by Mass Spectrometry. I

The kinetics of the ester-ester exchange reaction between polyesters from adipic acid and various linear and branched glycols were investigated by mass spectometry using the dimer analysis method (DAM). Rate constants, activation energies, and frequency factors are given for reactions studied in the temperature range of 572–585 K. Correlation of glycol methylene ratios with activation energies and frequency factors shows an alternating trend in kinetic behavior. Reaction systems containing even numbers of methylene groups in the glycol moiety of the reactants exhibited slower reaction rates than systems with odd numbers of methylene groups, while branched reaction systems followed very similar trends when the influence of pendant groups is ignored.