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Kinetics of polycarbonate glycolysis in ethylene glycol / Dongpil Kim in Industrial & engineering chemistry research, Vol. 48 N°2 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 685–691 Titre : Kinetics of polycarbonate glycolysis in ethylene glycol Type de document : texte imprimé Auteurs : Dongpil Kim, Auteur ; Bo-kyung Kim, Auteur ; Youngmin Cho, Auteur ; Myungwan Han, Auteur Année de publication : 2009 Article en page(s) : p. 685–691 Note générale : chemical engenireeng Langues : Anglais (eng) Mots-clés : polycarbonate Résumé : Depolymerization of polycarbonate waste by glycolysis using ethylene glycol without catalyst was explored in order to get the monomer bisphenol A (BPA). The depolymerized products were identified by GC/MS and FTIR spectroscopy. The effects of operation variables such as reaction time, reaction temperature, ethylene glycol/polycarbonate (EG/PC) weight ratio, and the kinetics of glycolysis were studied. A maximum yield of BPA of 95.6% was achieved at a reaction temperature of 220 °C for 85 min with an EG/PC weight ratio 4. It was found that the depolymerization reaction has two different activation energies, indicating that the reaction occurs in series. A new model was proposed to explain the depolymerization reaction which consists of a series of reactions: random scission from high molecular weight PC to its solid oligomer, dissolution from the solid oligomer to liquid oligomer, and homogeneous degradation from the liquid oligomer to its monomer, BPA. The activation energies were found to be 98.9 kJ/mol for the random scission reaction, 32.7 kJ/mol for the dissolution, and 355.8 kJ/mol for the homogeneous reaction, respectively. The predicted values by the proposed model were shown in good agreement with the experimental ones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010947 [article] Kinetics of polycarbonate glycolysis in ethylene glycol [texte imprimé] / Dongpil Kim, Auteur ; Bo-kyung Kim, Auteur ; Youngmin Cho, Auteur ; Myungwan Han, Auteur . - 2009 . - p. 685–691. chemical engenireeng Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°2 (Janvier 2009) . - p. 685–691 Mots-clés : polycarbonate Résumé : Depolymerization of polycarbonate waste by glycolysis using ethylene glycol without catalyst was explored in order to get the monomer bisphenol A (BPA). The depolymerized products were identified by GC/MS and FTIR spectroscopy. The effects of operation variables such as reaction time, reaction temperature, ethylene glycol/polycarbonate (EG/PC) weight ratio, and the kinetics of glycolysis were studied. A maximum yield of BPA of 95.6% was achieved at a reaction temperature of 220 °C for 85 min with an EG/PC weight ratio 4. It was found that the depolymerization reaction has two different activation energies, indicating that the reaction occurs in series. A new model was proposed to explain the depolymerization reaction which consists of a series of reactions: random scission from high molecular weight PC to its solid oligomer, dissolution from the solid oligomer to liquid oligomer, and homogeneous degradation from the liquid oligomer to its monomer, BPA. The activation energies were found to be 98.9 kJ/mol for the random scission reaction, 32.7 kJ/mol for the dissolution, and 355.8 kJ/mol for the homogeneous reaction, respectively. The predicted values by the proposed model were shown in good agreement with the experimental ones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8010947

Kinetics of polycarbonate methanolysis by a consecutive reaction model / Dongpil Kim in Industrial & engineering chemistry research, Vol. 48 N° 14 (Juillet 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6591–6599 Titre : Kinetics of polycarbonate methanolysis by a consecutive reaction model Type de document : texte imprimé Auteurs : Dongpil Kim, Auteur ; Bo-kyung Kim, Auteur ; Youngmin Cho, Auteur Année de publication : 2009 Article en page(s) : pp. 6591–6599 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Polycarbonate  particles  Methanol  Bisphenol  A  Dimethyl  carbonate Résumé : Polycarbonate (PC) particles were depolymerized by methanol to recover bisphenol A (BPA) and dimethyl carbonate (DMC) in the range of 160−220 °C without using a catalyst or toxic solvents. The effect of operation variables such as methanol/polycarbonate (MeOH/PC) weight ratio and the ethylene glycol/methanol (EG/MeOH) cosolvent system on reaction yields was examined to get better monomer yields. The product yield increased as the amount of methanol increased until the MeOH/PC molar ratio 71. However, the EG/MeOH cosolvent system did not improve the depolymerization yield. A novel kinetic model was proposed to explain the depolymerization reaction, which consists of a series of reactions: random scission from high molecular weight PC to its solid oligomer, dissolution from the solid oligomer to liquid oligomer, and homogeneous degradation from the oligomer to its monomers, BPA and DMC. Continuous distribution kinetics and shrinking core model were employed to describe random scission of PC and dissolution of PC solid particle in methanol solution. The predicted values by the proposed model were shown in good agreement with the experimental ones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801893v [article] Kinetics of polycarbonate methanolysis by a consecutive reaction model [texte imprimé] / Dongpil Kim, Auteur ; Bo-kyung Kim, Auteur ; Youngmin Cho, Auteur . - 2009 . - pp. 6591–6599. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6591–6599 Mots-clés : Polycarbonate  particles  Methanol  Bisphenol  A  Dimethyl  carbonate Résumé : Polycarbonate (PC) particles were depolymerized by methanol to recover bisphenol A (BPA) and dimethyl carbonate (DMC) in the range of 160−220 °C without using a catalyst or toxic solvents. The effect of operation variables such as methanol/polycarbonate (MeOH/PC) weight ratio and the ethylene glycol/methanol (EG/MeOH) cosolvent system on reaction yields was examined to get better monomer yields. The product yield increased as the amount of methanol increased until the MeOH/PC molar ratio 71. However, the EG/MeOH cosolvent system did not improve the depolymerization yield. A novel kinetic model was proposed to explain the depolymerization reaction, which consists of a series of reactions: random scission from high molecular weight PC to its solid oligomer, dissolution from the solid oligomer to liquid oligomer, and homogeneous degradation from the oligomer to its monomers, BPA and DMC. Continuous distribution kinetics and shrinking core model were employed to describe random scission of PC and dissolution of PC solid particle in methanol solution. The predicted values by the proposed model were shown in good agreement with the experimental ones. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801893v