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Quantitative research on the vaporization and decomposition of [EMIM] [Tf2N] by thermogravimetric analysis – mass spectrometry / Yu Chen in Industrial & engineering chemistry research, Vol. 51 N° 21 (Mai 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 21 (Mai 2012) . - pp. 7418–7427 Titre : Quantitative research on the vaporization and decomposition of [EMIM] [Tf2N] by thermogravimetric analysis – mass spectrometry Type de document : texte imprimé Auteurs : Yu Chen, Auteur ; Yuanyuan Cao, Auteur ; Yang Shi, Auteur Année de publication : 2012 Article en page(s) : pp. 7418–7427 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Thermogravimetric  analysis  Mass  spectrometry Résumé : The thermal stability of [EMIM][Tf2N] was investigated by thermogravimetric analysis–mass spectrometry (TG–MS) in this study. It showed that [EMIM][Tf2N] decomposed at temperatures over 350 °C by Hoffman elimination and substitution of nucleophilic mechanisms (SN, including the unimolecular substitution nucleophilic reaction SN1 and the bimolecular substitution nucleophilic reaction SN2). The instability of [EMIM][Tf2N] is induced by decomposition of the anion [Tf2N] to a more nucleophilic group, such as NH2 and F, and then methyl and/or ethyl in the imidazolium cation are attacked by those groups of relatively high nucleophilic activity. Mass loss of [EMIM][Tf2N] in a nitrogen atmosphere can be attributed to its decomposition and/or vaporization. The ratios of decomposition and vaporization (Dec/Vap), elimination and SN (Elim/SN), and SN2/SN1 for [EMIM][Tf2N] were approximately determined by TG–MS. The thermal stability including both decomposition and vaporization of [EMIM][Tf2N] decreases with an increase of the temperature, while decomposition is more sensitive to the temperature than evaporation. Vaporization of [EMIM][Tf2N] dominates the mass loss at temperatures below 350 °C, while decomposition dominates the mass loss at temperatures over 350 °C. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300247v [article] Quantitative research on the vaporization and decomposition of [EMIM] [Tf2N] by thermogravimetric analysis – mass spectrometry [texte imprimé] / Yu Chen, Auteur ; Yuanyuan Cao, Auteur ; Yang Shi, Auteur . - 2012 . - pp. 7418–7427. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 21 (Mai 2012) . - pp. 7418–7427 Mots-clés : Thermogravimetric  analysis  Mass  spectrometry Résumé : The thermal stability of [EMIM][Tf2N] was investigated by thermogravimetric analysis–mass spectrometry (TG–MS) in this study. It showed that [EMIM][Tf2N] decomposed at temperatures over 350 °C by Hoffman elimination and substitution of nucleophilic mechanisms (SN, including the unimolecular substitution nucleophilic reaction SN1 and the bimolecular substitution nucleophilic reaction SN2). The instability of [EMIM][Tf2N] is induced by decomposition of the anion [Tf2N] to a more nucleophilic group, such as NH2 and F, and then methyl and/or ethyl in the imidazolium cation are attacked by those groups of relatively high nucleophilic activity. Mass loss of [EMIM][Tf2N] in a nitrogen atmosphere can be attributed to its decomposition and/or vaporization. The ratios of decomposition and vaporization (Dec/Vap), elimination and SN (Elim/SN), and SN2/SN1 for [EMIM][Tf2N] were approximately determined by TG–MS. The thermal stability including both decomposition and vaporization of [EMIM][Tf2N] decreases with an increase of the temperature, while decomposition is more sensitive to the temperature than evaporation. Vaporization of [EMIM][Tf2N] dominates the mass loss at temperatures below 350 °C, while decomposition dominates the mass loss at temperatures over 350 °C. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie300247v

Thermostable microspheres consisting of poly(N-phenylmaleimide-co-α-methyl styrene) prepared by precipitation polymerization / Yu Chen in Industrial & engineering chemistry research, Vol. 51 N° 48 (Décembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 48 (Décembre 2012) . - pp. 15610-15617 Titre : Thermostable microspheres consisting of poly(N-phenylmaleimide-co-α-methyl styrene) prepared by precipitation polymerization Type de document : texte imprimé Auteurs : Yu Chen, Auteur ; Linyue Tong, Auteur ; Dongyue Zhang, Auteur Année de publication : 2013 Article en page(s) : pp. 15610-15617 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Polymerization  Microsphere Résumé : General polymeric microspheres are not satisfactorily thermostable. This article reports on an unprecedented type of poly(N-phenylmaleimide-co-α-methyl styrene) [denoted as poly(N-PMI-co-AMS)] microspheres showing remarkable thermal stability. The microspheres were prepared by free-radical precipitation polymerization in a solvent mixture consisting of methyl ethyl ketone (favorable solvent) and heptane (unfavorable solvent). Microspheres of good morphology and narrow size distribution were obtained in high yield (>85%) under appropriate conditions. Growth of poly(N-PMI-co-AMS) microspheres was characterized by scanning electron microscopy. The microspheres, although without cross-linking, exhibited excellent thermal stability, and their decomposition temperature was up to about 370 °C. This feature cannot be achieved in typical polymeric microspheres. Also, notably, this is the first precipitation polymerization of maleimide and AMS and their derivatives for preparing microspheres. The present novel microspheres are expected to find practical applications as novel heat-resistant additives, solid carriers for catalysts, and so on. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26710599 [article] Thermostable microspheres consisting of poly(N-phenylmaleimide-co-α-methyl styrene) prepared by precipitation polymerization [texte imprimé] / Yu Chen, Auteur ; Linyue Tong, Auteur ; Dongyue Zhang, Auteur . - 2013 . - pp. 15610-15617. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 48 (Décembre 2012) . - pp. 15610-15617 Mots-clés : Polymerization  Microsphere Résumé : General polymeric microspheres are not satisfactorily thermostable. This article reports on an unprecedented type of poly(N-phenylmaleimide-co-α-methyl styrene) [denoted as poly(N-PMI-co-AMS)] microspheres showing remarkable thermal stability. The microspheres were prepared by free-radical precipitation polymerization in a solvent mixture consisting of methyl ethyl ketone (favorable solvent) and heptane (unfavorable solvent). Microspheres of good morphology and narrow size distribution were obtained in high yield (>85%) under appropriate conditions. Growth of poly(N-PMI-co-AMS) microspheres was characterized by scanning electron microscopy. The microspheres, although without cross-linking, exhibited excellent thermal stability, and their decomposition temperature was up to about 370 °C. This feature cannot be achieved in typical polymeric microspheres. Also, notably, this is the first precipitation polymerization of maleimide and AMS and their derivatives for preparing microspheres. The present novel microspheres are expected to find practical applications as novel heat-resistant additives, solid carriers for catalysts, and so on. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26710599