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Reaction mechanism and kinetics of dimethyl carbonate synthesis from methyl carbamate and methanol / Wenbo Zhao in Industrial & engineering chemistry research, Vol. 51 N° 51 (Décembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16580–16589 Titre : Reaction mechanism and kinetics of dimethyl carbonate synthesis from methyl carbamate and methanol Type de document : texte imprimé Auteurs : Wenbo Zhao, Auteur ; Xianye Qin, Auteur ; Yanhong Li, Auteur Année de publication : 2012 Article en page(s) : pp. 16580–16589 Note générale : Induistrial chemistry Langues : Anglais (eng) Mots-clés : Kinetics  Carbonate  Methanol Résumé : The catalytic activities of many transition-metal salts for dimethyl carbonate (DMC) synthesis from methyl carbamate (MC) and methanol were evaluated in a batch reactor. The reaction mechanism and kinetics on the outstanding catalyst ZnCl2 were further investigated in detail. X-ray diffraction (XRD), thermogravimetry (TG), and differential scanning calorimetry (DSC) characterization, quantum chemical calculation, and kinetics experiments all indicated that this reaction could be divided into two processes: (1) two MC molecules coordinated with ZnCl2 via N atom to produce Zn(MC)2Cl2. This intermediate would convert to Zn(MC)(NH3)Cl2 by reacting with one methanol molecule. This process was first order, relative to ZnCl2, and zeroeth order, relative to MC, from a macrokinetics viewpoint. (2) Zn(MC)(NH3)Cl2 further reacted with another methanol molecule to yield DMC and Zn(NH3)2Cl2, one ammonia molecule of Zn(NH3)2Cl2 could be substituted by MC at experimental temperature to form Zn(MC)(NH3)Cl2 again. This process was first order to both ZnCl2 and MC, from a macrokinetics viewpoint. It should be noted that Zn(MC)2Cl2 could not appear again after the first process, and the second process is the real catalysis cycle in DMC synthesis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302245n [article] Reaction mechanism and kinetics of dimethyl carbonate synthesis from methyl carbamate and methanol [texte imprimé] / Wenbo Zhao, Auteur ; Xianye Qin, Auteur ; Yanhong Li, Auteur . - 2012 . - pp. 16580–16589. Induistrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 51 (Décembre 2012) . - pp. 16580–16589 Mots-clés : Kinetics  Carbonate  Methanol Résumé : The catalytic activities of many transition-metal salts for dimethyl carbonate (DMC) synthesis from methyl carbamate (MC) and methanol were evaluated in a batch reactor. The reaction mechanism and kinetics on the outstanding catalyst ZnCl2 were further investigated in detail. X-ray diffraction (XRD), thermogravimetry (TG), and differential scanning calorimetry (DSC) characterization, quantum chemical calculation, and kinetics experiments all indicated that this reaction could be divided into two processes: (1) two MC molecules coordinated with ZnCl2 via N atom to produce Zn(MC)2Cl2. This intermediate would convert to Zn(MC)(NH3)Cl2 by reacting with one methanol molecule. This process was first order, relative to ZnCl2, and zeroeth order, relative to MC, from a macrokinetics viewpoint. (2) Zn(MC)(NH3)Cl2 further reacted with another methanol molecule to yield DMC and Zn(NH3)2Cl2, one ammonia molecule of Zn(NH3)2Cl2 could be substituted by MC at experimental temperature to form Zn(MC)(NH3)Cl2 again. This process was first order to both ZnCl2 and MC, from a macrokinetics viewpoint. It should be noted that Zn(MC)2Cl2 could not appear again after the first process, and the second process is the real catalysis cycle in DMC synthesis. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie302245n