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Development of a novel hollow fiber ccation-exchange membrane from bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) for removal of heavy-metal ions / Zhenfeng Cheng in Industrial & engineering chemistry research, Vol. 49 N° 7 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3079–3087 Titre : Development of a novel hollow fiber ccation-exchange membrane from bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) for removal of heavy-metal ions Type de document : texte imprimé Auteurs : Zhenfeng Cheng, Auteur ; Yonghui Wu, Auteur ; Na Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 3079–3087 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Hollow  Fiber  Cation-Exchange  Membrane  Bromomethylated  Poly  Heavy-Metal  Ions  dimethy  phenylene  oxide  phenyleemoval Résumé : A novel hollow fiber cation-exchange membrane was prepared from a bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) hollow fiber by amination and sulfonation. The membrane exhibited good performance for adsorption of Cu2+, and its maximum capacity can reach 69.12 mg/g. In particular, the adsorption capacity increased with an increase in adsorption time, initial Cu2+ concentration, and ion-exchange capacity of the membrane, and the adsorption isotherms were of Langmuir and Freundlich types. When these membranes were taken for desorption in solutions of hydrochloric acid, the regeneration ratio increased with an increase in regeneration time (before 20 min) and acid concentration. This study can provide new material for removal of heavy-metal ions in an energy-saving manner. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901408c [article] Development of a novel hollow fiber ccation-exchange membrane from bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) for removal of heavy-metal ions [texte imprimé] / Zhenfeng Cheng, Auteur ; Yonghui Wu, Auteur ; Na Wang, Auteur . - 2010 . - pp. 3079–3087. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 7 (Avril 2010) . - pp. 3079–3087 Mots-clés : Hollow  Fiber  Cation-Exchange  Membrane  Bromomethylated  Poly  Heavy-Metal  Ions  dimethy  phenylene  oxide  phenyleemoval Résumé : A novel hollow fiber cation-exchange membrane was prepared from a bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) hollow fiber by amination and sulfonation. The membrane exhibited good performance for adsorption of Cu2+, and its maximum capacity can reach 69.12 mg/g. In particular, the adsorption capacity increased with an increase in adsorption time, initial Cu2+ concentration, and ion-exchange capacity of the membrane, and the adsorption isotherms were of Langmuir and Freundlich types. When these membranes were taken for desorption in solutions of hydrochloric acid, the regeneration ratio increased with an increase in regeneration time (before 20 min) and acid concentration. This study can provide new material for removal of heavy-metal ions in an energy-saving manner. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901408c

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

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