Kinetic modelling of crosslinking reactions for cycloaliphatic epoxides with hydroxyl- and carboxyl-functionalized acrylic copolymers: 1. pH and temperature effects

The crosslinking kinetics and reaction mechanism of cycloaliphatic epoxides with both hydroxyl and carboxyl functional groups were studied by using cyclohexene oxide, methanol and acetic acid as model compounds. The reactions of cyclohexene oxide with methanol and acetic acid were performed as a function of pH and temperature. The major products isolated from the reaction system were trans-2-acetoxyl cyclohexanol and trans-2-methoxyl cyclohexenol. However, none of the corresponding cis isomer was observed. The reaction order was determined to be first order in acetic add and cyclohexene oxide for trans-2-acetoxyl cyclohexenol, and first order in methanol, cyclohexene oxide and proton concentration for trans-2-methoxyl cyclohexenol. The reaction rate constants, reaction orders, activation energies, activation enthalpies and entropies for the formation of the products in the reactions were determined for the competitive system. Based upon the stereochemistry of the products and the kinetic data, an A-2 type mechanism is proposed for both major products. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.