解聚
化学
差示扫描量热法
活化能
动力学
化学动力学
吉布斯自由能
反应速率
反应机理
聚对苯二甲酸乙二醇酯
材料科学
高分子化学
热力学
物理化学
有机化学
催化作用
物理
量子力学
复合材料
作者
Saqib Javed,Jonas Fisse,Dieter Vogt
标识
DOI:10.1021/acs.iecr.2c04308
摘要
Reaction kinetics provides significant insights into the reaction rate and mechanism to control a chemical reaction. In the present work, the detailed kinetics of glycolytic depolymerization of post-consumer polyethylene terephthalate (PET) waste in the presence of sodium ethoxide (EtONa) was investigated. The glycolysis experiments were conducted in a batch reactor over a temperature range of 160 to 197 °C. The confirmation of the product, the bis(2-hydroxyethyl)terephthalate monomer, was carried out using nuclear magnetic resonance spectroscopy, high-performance liquid chromatography, differential scanning calorimetry, and X-ray diffraction techniques. Investigations on the influence of particle size and temperature showed that conversion increased with a decrease in particle size and increasing temperature. Equilibrium conversions were found at different temperatures, and a van 't Hoff plot was used to confirm that the depolymerization reaction is endothermic. Gibbs' free energy was used to calculate the ceiling temperature (TC = 156 °C). Three kinetic models were tested for their applicability. It was found that the EtONa-catalyzed glycolysis of PET follows a first-order reversible reaction kinetic model at higher temperatures (170–197 °C). However, a heterogeneous shrinking core mechanism was applicable in a lower temperature range (160–170 °C). The kinetic evaluation revealed that the PET glycolysis reaction consists of heterogeneous and homogeneous mechanisms depending upon the depolymerization stages at various temperatures.
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