The kinetics of reversible (2+4)-cycloaddition of methyl acrylate to furan at 343.7K

The current concentrations of the initial compounds and the products of the forward and back Diels-Alder reactions between furan and methyl acrylate were measured by the proton NMR method. The experimental data were approximated by spline functions to obtain the reaction time dependences of concentration ratios and their derivatives, which were used to calculate the rate constants for the formation and decomposition of the exo and endo adducts from the differential equations corresponding to the mechanism of the process, which excluded direct interconversions of the adducts. The rate constants for system movement to equilibrium from both sides experienced oscillations, probably, because of the existence of energy chains. Averaging by repeat spline approximation reduced these dependences to curves with a single minimum in the region of equilibrium concentrations, whereas the ratios between the rate constants for the forward and back reactions (equilibrium constants) remained virtually unchanged.