Kinetic Features of an Intraresin Reaction

Article abstract of DOI:10.1021/ja00344a024

The kinetic features of the intraresin displacement by pendant ammonium acetate groups on chloromethylated polystyrene have been investigated as a function of temperature, swelling solvent, and cross-link density.In all cases, intraresin displasement proceeds with a rapid initial rate folowed by a very slow second stage; the latter represents that fraction of reactant which become "kinetically isolated".The free energy of activation for the first stage, under the various swelling conditions used, lies in the range 24.4-26.8 kcal mol^-1, which is similar to that found for analogous homogeneous reactions.The absolute rates measured for the homogeneous and the initial intraresin displacement in dioxane were similar; with n-hexane and toluene as solvents, polymeric rates were considerably slower than those of their homogeneous counterparts.Intraresin displacement was rapid even when a poor swelling solvent (n-hexane) was used.As the rate of intrapolymeric reaction decreased (through a decrease in temperature, increase in cross-link density, or change in solvent) the percent of "kinetically isolated" sites increased.