No abstract

No abstract

ObstractIn the present work, the depolymerization of polyethylene terephthalate (PET) was performed by the method of glycolysis with ethylene glycol. The process was carried out using a factorial design in the Box-Behnken optimization model, using a response surface methodology (RSM) in which three factors (time, temperature and mass ratio of ethylene glycol) were studied in three levels of variation (-1, 0, +1) with two replicates of the center point, totalizing 15 experiments for which the yield of bis (2-hydroxyethyl) terephthalate (BHET) monomers formed in the process was chosen as response. In parallel, the Arrhenius kinetic test was used to determine the apparent activation energy (Ea) for the 1-butyl-3-methylimidazole trichlorozincate ([Bmin]ZnCl 3 ) -catalyst used in the depolymerization process. The products of glycolysis obtained were characterized by spectroscopic techniques (FTIR), ( 1 H and 13 C NMR), thermal analyses (TGA) and (DSC) and Mass Spectrometry LC-MS/MS hybrid Quadrupole-Orbitrap.

This work reports experimental and computational studies of polyurethanes depolymerization from industrial waste through a reaction with potassium hydroxide. A computational study was performed to identify the chemical reaction mechanism, which is more difficult to determine experimentally. Kinetic and thermodynamic parameters of activation process were also obtained by theoretical calculations. An experimental procedure led to products identified by 13C solid‐state NMR analysis, which agree to the computational study. A small variation of less than 5% in the activation energy values found between the data obtained through theoretical calculations and experimental methods suggests that the described computational procedure is enough to describe the process in a satisfactory manner.

No abstract