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Direct synthesis of dimethyl toluene - 2,4 - dicarbamate from 2,4 - toluene diamine, urea, and methanol / Xinqiang Zhao in Industrial & engineering chemistry research, Vol. 50 N° 24 (Décembre 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 24 (Décembre 2011) . - pp. 13636–13641 Titre : Direct synthesis of dimethyl toluene - 2,4 - dicarbamate from 2,4 - toluene diamine, urea, and methanol Type de document : texte imprimé Auteurs : Xinqiang Zhao, Auteur ; Na Wang, Auteur ; Yanlou Geng, Auteur Année de publication : 2012 Article en page(s) : pp. 13636–13641 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Dimethyl  Toluene  Dicarbamate Résumé : Dimethyl toluene-2,4-dicarbamate (TDC) was directly synthesized from 2,4-toluene diamine (TDA), urea, and methanol in order to overcome the drawbacks of other technological routes to TDC. First the thermodynamic analysis for this reaction was made and the results show that the reaction is endothermic and can occur spontaneously beyond 413.8 K. Then the effects of catalyst and reaction conditions were studied. TDA conversion of 98.8% and TDC selectivity of 41.6% were attained in the presence of zinc chloride catalyst and under the suitable conditions of molar ratio of TDA/zinc chloride/urea/methanol = 1/0.07/5/80, reaction temperature of 190 °C, reaction pressure of 3.0 MPa, and reaction time of 9 h. Low TDC selectivity is attributed to the difficulty in the conversion of the intermediates, methyl 2-methyl-5-amino N-phenylcarbamate (TMC1) and methyl 3-amino-4-methyl-N-phenylcarbamate (TMC2), to TDC. Finally on the basis of analyses of HPLC–MS, HPLC, and GC, three possible reaction paths were proposed. One path is the reaction of TDA with urea to toluene-2,4-bisurea (TBU) and then the formation of TDC from the succeeding reaction of TBU with methanol. Another path is the generation of TMC1 and TMC2 from the reaction of TDA with first urea and then methanol, and the succeeding reaction of the formed TMC1 and TMC2 with first urea and then methanol to TDC. Still another path is the formation of methyl carbamate (MC) by the reaction of urea and methanol and then the reaction of TDA with MC to TMC1 and TMC2, and finally a further reaction of TMC1 and TMC2 with MC to TDC. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201891p [article] Direct synthesis of dimethyl toluene - 2,4 - dicarbamate from 2,4 - toluene diamine, urea, and methanol [texte imprimé] / Xinqiang Zhao, Auteur ; Na Wang, Auteur ; Yanlou Geng, Auteur . - 2012 . - pp. 13636–13641. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 24 (Décembre 2011) . - pp. 13636–13641 Mots-clés : Dimethyl  Toluene  Dicarbamate Résumé : Dimethyl toluene-2,4-dicarbamate (TDC) was directly synthesized from 2,4-toluene diamine (TDA), urea, and methanol in order to overcome the drawbacks of other technological routes to TDC. First the thermodynamic analysis for this reaction was made and the results show that the reaction is endothermic and can occur spontaneously beyond 413.8 K. Then the effects of catalyst and reaction conditions were studied. TDA conversion of 98.8% and TDC selectivity of 41.6% were attained in the presence of zinc chloride catalyst and under the suitable conditions of molar ratio of TDA/zinc chloride/urea/methanol = 1/0.07/5/80, reaction temperature of 190 °C, reaction pressure of 3.0 MPa, and reaction time of 9 h. Low TDC selectivity is attributed to the difficulty in the conversion of the intermediates, methyl 2-methyl-5-amino N-phenylcarbamate (TMC1) and methyl 3-amino-4-methyl-N-phenylcarbamate (TMC2), to TDC. Finally on the basis of analyses of HPLC–MS, HPLC, and GC, three possible reaction paths were proposed. One path is the reaction of TDA with urea to toluene-2,4-bisurea (TBU) and then the formation of TDC from the succeeding reaction of TBU with methanol. Another path is the generation of TMC1 and TMC2 from the reaction of TDA with first urea and then methanol, and the succeeding reaction of the formed TMC1 and TMC2 with first urea and then methanol to TDC. Still another path is the formation of methyl carbamate (MC) by the reaction of urea and methanol and then the reaction of TDA with MC to TMC1 and TMC2, and finally a further reaction of TMC1 and TMC2 with MC to TDC. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201891p

MgO-PbO catalyzed synthesis of diethylene glycol Bis(allyl carbonate) by transesterification route / Hualiang An in Industrial & engineering chemistry research, Vol. 50 N° 13 (Juillet 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 7740–7745 Titre : MgO-PbO catalyzed synthesis of diethylene glycol Bis(allyl carbonate) by transesterification route Type de document : texte imprimé Auteurs : Hualiang An, Auteur ; Zhuo Gao, Auteur ; Xinqiang Zhao, Auteur Année de publication : 2011 Article en page(s) : pp. 7740–7745 Note générale : Chimlie industrielle Langues : Anglais (eng) Mots-clés : Mixed  metal  oxides  Synthesis  of  diethylene Résumé : The catalytic performance of mixed metal oxides was evaluated for the synthesis of diethylene glycol bis(allyl carbonate) (ADC) by transesterification of diethylene glycol (DEG), dimethyl carbonate (DMC). and allyl alcohol (AAH), and MgO–PbO was found to show the highest catalytic activity. The influence of preparation conditions on the catalytic performance of MgO–PbO was studied and its suitable preparation conditions were as follows. A calcination process was used, with Mg(OH)2 and Pb(CH3COO)2·3H2O as precursors, molar ratio of Mg:Pb = 6:1, and calcination temperature of 650 °C. Under the following reaction conditions, molar ratio of DEG:DMC:AAH = 0.08:1:2, weight percentage of MgO–PbO = 1.5% of total weight of all reactants, 100 °C, 6 h, and vacuum of 0.08 MPa, the yield of ADC was 97.3%. Moreover, MgO–PbO showed a good recyclability; ADC yield of 95.4% could be achieved after the catalyst was reused for two times. The results of N2 adsorption–desorption measurement and XPS analyses for MgO–PbO indicate there exists an interaction between MgO and PbO, which promotes the catalytic performance and recyclability of MgO–PbO. Furthermore, the reaction pathway for ADC synthesis was elucidated by means of GC-MS analysis and experimental verification. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003076 [article] MgO-PbO catalyzed synthesis of diethylene glycol Bis(allyl carbonate) by transesterification route [texte imprimé] / Hualiang An, Auteur ; Zhuo Gao, Auteur ; Xinqiang Zhao, Auteur . - 2011 . - pp. 7740–7745. Chimlie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 7740–7745 Mots-clés : Mixed  metal  oxides  Synthesis  of  diethylene Résumé : The catalytic performance of mixed metal oxides was evaluated for the synthesis of diethylene glycol bis(allyl carbonate) (ADC) by transesterification of diethylene glycol (DEG), dimethyl carbonate (DMC). and allyl alcohol (AAH), and MgO–PbO was found to show the highest catalytic activity. The influence of preparation conditions on the catalytic performance of MgO–PbO was studied and its suitable preparation conditions were as follows. A calcination process was used, with Mg(OH)2 and Pb(CH3COO)2·3H2O as precursors, molar ratio of Mg:Pb = 6:1, and calcination temperature of 650 °C. Under the following reaction conditions, molar ratio of DEG:DMC:AAH = 0.08:1:2, weight percentage of MgO–PbO = 1.5% of total weight of all reactants, 100 °C, 6 h, and vacuum of 0.08 MPa, the yield of ADC was 97.3%. Moreover, MgO–PbO showed a good recyclability; ADC yield of 95.4% could be achieved after the catalyst was reused for two times. The results of N2 adsorption–desorption measurement and XPS analyses for MgO–PbO indicate there exists an interaction between MgO and PbO, which promotes the catalytic performance and recyclability of MgO–PbO. Furthermore, the reaction pathway for ADC synthesis was elucidated by means of GC-MS analysis and experimental verification. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie2003076

Synthesis of methyl N - phenyl carbamate catalyzed by ionic liquid - promoted zinc acetate / Xinqiang Zhao in Industrial & engineering chemistry research, Vol. 51 N° 35 (Septembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 35 (Septembre 2012) . - pp. 11335-11340 Titre : Synthesis of methyl N - phenyl carbamate catalyzed by ionic liquid - promoted zinc acetate Type de document : texte imprimé Auteurs : Xinqiang Zhao, Auteur ; Lijuan Kang, Auteur ; Na Wang, Auteur Année de publication : 2012 Article en page(s) : pp. 11335-11340 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Ionic  liquid  Catalytic  reaction Résumé : A series of ionic liquid-promoted zinc acetate catalysts (Zn(OAc)2-ILs) were prepared by separately mixing anhydrous zinc acetate with one of some ionic liquids, and their catalytic performance for the synthesis of methyl N-phenyl carbamate (MPC) from aniline and dimethyl carbonate (DMC) was evaluated. Among the catalysts, Zn(OAc)2-[bmim]PF6 showed the best catalytic performance. Under the suitable reaction conditions, aniline conversion and MPC selectivity were 99.8% and 99.1%, respectively. Moreover, Zn(OAc)2-[bmim]PF6 could be used five times without a significant loss in its catalytic performance. The mechanism for the promotion of ionic liquid [bmim]PF6 on the catalytic performance of zinc acetate was investigated by means of FT-IR analysis. The results show that a hydrogen bond is formed between the carbonyl oxygen of zinc acetate and the C2-H on an imidazoiume ring of [bmim]PF6. As a result, the zinc acetate changes from a bidentate to a unidentate coordination structure. Simultaneously, this change promotes the coordination of the carbonyl oxygen in a DMC molecule with the zinc atom in the zinc acetate molecule, faciliting the attack of the nitrogen atom in an aniline molecule on the carbonyl carbon in the coordinated DMC molecule and then the formation of MPC. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26324781 [article] Synthesis of methyl N - phenyl carbamate catalyzed by ionic liquid - promoted zinc acetate [texte imprimé] / Xinqiang Zhao, Auteur ; Lijuan Kang, Auteur ; Na Wang, Auteur . - 2012 . - pp. 11335-11340. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 35 (Septembre 2012) . - pp. 11335-11340 Mots-clés : Ionic  liquid  Catalytic  reaction Résumé : A series of ionic liquid-promoted zinc acetate catalysts (Zn(OAc)2-ILs) were prepared by separately mixing anhydrous zinc acetate with one of some ionic liquids, and their catalytic performance for the synthesis of methyl N-phenyl carbamate (MPC) from aniline and dimethyl carbonate (DMC) was evaluated. Among the catalysts, Zn(OAc)2-[bmim]PF6 showed the best catalytic performance. Under the suitable reaction conditions, aniline conversion and MPC selectivity were 99.8% and 99.1%, respectively. Moreover, Zn(OAc)2-[bmim]PF6 could be used five times without a significant loss in its catalytic performance. The mechanism for the promotion of ionic liquid [bmim]PF6 on the catalytic performance of zinc acetate was investigated by means of FT-IR analysis. The results show that a hydrogen bond is formed between the carbonyl oxygen of zinc acetate and the C2-H on an imidazoiume ring of [bmim]PF6. As a result, the zinc acetate changes from a bidentate to a unidentate coordination structure. Simultaneously, this change promotes the coordination of the carbonyl oxygen in a DMC molecule with the zinc atom in the zinc acetate molecule, faciliting the attack of the nitrogen atom in an aniline molecule on the carbonyl carbon in the coordinated DMC molecule and then the formation of MPC. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26324781

Synthesis of methyl N-phenyl carbamate from aniline and dimethyl carbonate over supported zirconia catalyst / Fang, Li in Industrial & engineering chemistry research, Vol. 47 N° 13 (Juillet 2008)

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N° 13 (Juillet 2008) . - p. 4560–4560 Titre : Synthesis of methyl N-phenyl carbamate from aniline and dimethyl carbonate over supported zirconia catalyst Type de document : texte imprimé Auteurs : Fang, Li, Auteur ; Jing Miao, Auteur ; Yanji Wang, Auteur ; Xinqiang Zhao, Auteur Année de publication : 2008 Article en page(s) : p. 4560–4560 Note générale : Bibliogr. p. 4560 Langues : Anglais (eng) Note de contenu : Additions and corrections of Volume 45 N° 14 [article] Synthesis of methyl N-phenyl carbamate from aniline and dimethyl carbonate over supported zirconia catalyst [texte imprimé] / Fang, Li, Auteur ; Jing Miao, Auteur ; Yanji Wang, Auteur ; Xinqiang Zhao, Auteur . - 2008 . - p. 4560–4560. Bibliogr. p. 4560 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 13 (Juillet 2008) . - p. 4560–4560 Note de contenu : Additions and corrections of Volume 45 N° 14