PET glycolysis optimization using ionic liquid [Bmin]ZnCl3 as catalyst and kinetic evaluation

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.

Investigating the degradation of PET utilizing NHC‐based catalysts and effective reuse of the degradation product as an additive with polyurethane adhesive material

“…On the other hand, BHET spectra (Figure 4b) displayed highly narrow peaks indicating the crystallinity and purity of the monomer obtained after depolymerization of PET. The characteristics of BHET peaks appeared at a respective region, which was well matched with the literature reports 9,25 . More importantly, the appearance of a new intense peak at 3450 cm −1 due to the presence of hydroxyl groups in the case of BHET proved the conversion of PET into its monomer, BHET.…”

“…In most cases, glycolysis employs excess ethylene glycol as a reagent to break ester bonds of PET to obtain its monomer. The quality of the degradation product obtained by the glycolysis process is often much higher; as a result, it can be further reused while producing fine chemicals 9,10 . However, in the absence of the catalyst, the rate of glycolysis is very slow; hence ionic liquids‐based catalytic systems have emerged as an effective catalyst for the degradation of PET by being a green solvent with nonvolatile behavior, high thermal and chemical stability, and low inflammability 11,12 .…”

Optimization and Kinetic Evaluation for Glycolytic Depolymerization of Post-Consumer PET Waste with Sodium Methoxide

“…The melting point of unconverted PET residue was also measured and it was found that residue starts melting around 162 °C but melts completely around 168 °C corresponding to the dimer melting temperature range [ 38 ]. The melting point of BHET is in accordance as reported in various studies 109–110 [ 39 ], 111 [ 40 ] and 113.34 °C [ 41 ] via DSC-analysis. The melting point analysis is further supported by DSC analysis ( Figure S5 ) which shows that PET residue comprises only monomer and dimer peaks.…”

Optimization of Ti–BA efficiently for the catalytic alcoholysis of waste PET using response surface methodology

“…According to the type of catalyst, the alcohololysis mechanism is mainly divided into two types but the same point is that under the cooperation of alcohol, the active centers of the catalyst attack the carbonyl group to realize the degradation of PET. [23][24][25][26] Response surface methodology (RSM) is an effective tool and means to optimize a chemical process, which is the combination of designing experiments, establishing experimental models, and evaluating the inuence of variables and their interactions. 27,28 The main advantage of RSM is that it reduces the number of experiments, so it requires fewer levels and can evaluate independent variables and their interactions.…”