Transesterification reaction of poly(ethylene-co-vinyl acetate) with alcohols. A kinetic study in solution and in the bulk

The chemical kinetics of the transesterification reaction of poly(ethylene-co-vinyl acetate) (EVA) with aliphatic alcohols were investigated, both in solution and in bulk, in the presence of dibutyl tin dilaurate (DBTDL) as the catalyst. A Fourier Transform infrared spectrometer (FTIR) was utilized for the measurement of the extent of the reaction. Experimental results showed that the reaction carried out in solution and in the bulk follows the same mechanism, namely, a reversible second order reaction of which the equilibrium only slightly increases with temperature. Additionally, the overall forward and reverse rate constants are proportional to the square root of the concentration of the catalyst. This study has also revealed that the intrinsic rate constants in solution and in the bulk are the same, regardless of the differences in the physical conditions encountered in the bulk and solution media, in particular, the reactant concentrations and viscosity of the reacting mixture. The effects of mechanical mixing are unimportant, since the reaction rate is relatively slow as compared with the rate of diffusion.