Insights into the thermal degradation mechanisms of polyethylene terephthalate dimer using DFT method

Expanding Plastics Recycling Technologies: Chemical Aspects, Technology Status and Challenges

“…[255][256][257] This reaction takes place through a six-membered transition state (39), and recent DFT studies predict activation and reaction energies of 184.0 and +48.0 kJ/mol, respectively. 258 The initiation reaction leads to the formation of an oligomer with an olefin end group (40) and another oligomer with a carboxylic end group (41). These two species decompose further to produce a wide spectrum of products with acetaldehyde (44) and CO2 (43) being the most abundant at temperatures around 300 o C. 256 The former can be produced directly from (40) and (41) or via the degradation of EG end groups as proposed by Holland and Hay, 259 while CO2 is released by decarboxylation of (41).…”

Expanding plastics recycling technologies: chemical aspects, technology status and challenges

“…[239][240][241] This reaction takes place through a six-membered transition state (39), and recent DFT studies predict activation and reaction energies of 184.0 and +48.0 kJ/mol, respectively. 242 The initiation reaction leads to the formation of an oligomer with an olefin end group (40) and another oligomer with a carboxylic end group (41). These two species decompose further to produce a wide spectrum of products with acetaldehyde (44) and CO2 (43) being the most abundant at temperatures around 300 o C. 240 The former can be produced directly from (40) and (41) or via the degradation of EG end groups as proposed by Holland and Hay, 243 while CO2 is released by decarboxylation of (41).…”

Efficient Degradation of High-Concentration Benzotriazole Wastewater via UV/H2O2/O3 Operation: Degradation Mechanism, Toxicological Evaluation, and Economic Analysis

“…The optimization of BTZ molecule was achieved by Gaussian 16W and GaussView 6.0 program, which was calculated at the B3LYP/6-31+ (d, p) level. The bond dissociation enthalpies (BDEs) are always considered as reaction energy barriers for radical reaction as AB = A· + B· . The values of BDEs were calculated by the formulation as following: E normalB normalD normalE = H ( A · ) + H ( B · ) − H ( A − B ) where E BDE is the BDE value in kJ/mol, and H is the thermal enthalpy value in kJ/mol.…”