Documents disponibles écrits par cet auteur

Cyclization of pseudoionone to β-Ionone / Madhvanand N. Kashid 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. 7920-7926 Titre : Cyclization of pseudoionone to β-Ionone : reaction mechanism and kinetics Type de document : texte imprimé Auteurs : Madhvanand N. Kashid, Auteur ; Igor Yuranov, Auteur ; Pauline Raspail, Auteur Année de publication : 2011 Article en page(s) : pp. 7920-7926 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Kinetics  Reaction  mechanism Résumé : Cyclization of pseudoionone (PI) to β-ionone is an important reaction used in the synthesis of vitamin A and in perfumery. Though the reaction is used for commercial production, its mechanism and kinetics are not known, and the same holds for the optimal performance of the process. This paper deals with experimental investigations of reaction mechanism and kinetics. The inherent characteristics of the reaction such as heat of reaction, thermal stability, and reactants/products distribution in biphasic (sulfuric acid-toluene) system was investigated experimentally. To overcome the mass transfer limitations, the intrinsic kinetics was studied in a batch reactor using a solvent (1-nitropropane) miscible with the reactant and the homogeneous catalyst. It was revealed that the reaction consists of two steps with the first being rapid, while the second is relatively slower. Therefore, the kinetics of only the second step was investigated which was observed to be first order with an activation energy of 65 kJ/mol. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332116 [article] Cyclization of pseudoionone to β-Ionone : reaction mechanism and kinetics [texte imprimé] / Madhvanand N. Kashid, Auteur ; Igor Yuranov, Auteur ; Pauline Raspail, Auteur . - 2011 . - pp. 7920-7926. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 13 (Juillet 2011) . - pp. 7920-7926 Mots-clés : Kinetics  Reaction  mechanism Résumé : Cyclization of pseudoionone (PI) to β-ionone is an important reaction used in the synthesis of vitamin A and in perfumery. Though the reaction is used for commercial production, its mechanism and kinetics are not known, and the same holds for the optimal performance of the process. This paper deals with experimental investigations of reaction mechanism and kinetics. The inherent characteristics of the reaction such as heat of reaction, thermal stability, and reactants/products distribution in biphasic (sulfuric acid-toluene) system was investigated experimentally. To overcome the mass transfer limitations, the intrinsic kinetics was studied in a batch reactor using a solvent (1-nitropropane) miscible with the reactant and the homogeneous catalyst. It was revealed that the reaction consists of two steps with the first being rapid, while the second is relatively slower. Therefore, the kinetics of only the second step was investigated which was observed to be first order with an activation energy of 65 kJ/mol. DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24332116

Influence of flow regime on mass transfer in different types of microchannels / Madhvanand N. Kashid in Industrial & engineering chemistry research, Vol. 50 N° 11 (Juin 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp. 6906-6914 Titre : Influence of flow regime on mass transfer in different types of microchannels Type de document : texte imprimé Auteurs : Madhvanand N. Kashid, Auteur ; Albert Renken, Auteur ; Lioubov Kiwi-Minsker, Auteur Année de publication : 2011 Article en page(s) : pp. 6906-6914 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mass  transfer  Flow  regime Résumé : The performance of microstructured reactors (or microchannels) for mass-transfer-controlled liquid―liquid reactions depends on flow regimes that define the specific interfacial area for the mass transfer. In the present work, experiments were carried out to investigate the two phase-flow regimes and the mass transfer at relatively high throughput for a single microchannel (of 1―18 mL/min) in five generic microchannel designs (with and without structured internal surfaces), using a nonreacting water-acetone-toluene system. When the flow results were analyzed collectively in all microchannels, six different flow regimes such as slug, slug-drop, deformed interface, parallel/ annular, slug-dispersed, and dispersed flow were observed. The mass-transfer comparison shows that the microchannel with structured internal surfaces shows better performance, because it creates a very fine dispersion, providing high interfacial area, compared to other microchannels. Finally, the mass-transfer data were correlated, which can be used for a priori predictions of mass-transfer rates in microchannels, DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24199908 [article] Influence of flow regime on mass transfer in different types of microchannels [texte imprimé] / Madhvanand N. Kashid, Auteur ; Albert Renken, Auteur ; Lioubov Kiwi-Minsker, Auteur . - 2011 . - pp. 6906-6914. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 11 (Juin 2011) . - pp. 6906-6914 Mots-clés : Mass  transfer  Flow  regime Résumé : The performance of microstructured reactors (or microchannels) for mass-transfer-controlled liquid―liquid reactions depends on flow regimes that define the specific interfacial area for the mass transfer. In the present work, experiments were carried out to investigate the two phase-flow regimes and the mass transfer at relatively high throughput for a single microchannel (of 1―18 mL/min) in five generic microchannel designs (with and without structured internal surfaces), using a nonreacting water-acetone-toluene system. When the flow results were analyzed collectively in all microchannels, six different flow regimes such as slug, slug-drop, deformed interface, parallel/ annular, slug-dispersed, and dispersed flow were observed. The mass-transfer comparison shows that the microchannel with structured internal surfaces shows better performance, because it creates a very fine dispersion, providing high interfacial area, compared to other microchannels. Finally, the mass-transfer data were correlated, which can be used for a priori predictions of mass-transfer rates in microchannels, DEWEY : 660 ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=24199908

Microstructured reactors for multiphase reactions / Madhvanand N. Kashid 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. 6465–6485 Titre : Microstructured reactors for multiphase reactions : state of the art Type de document : texte imprimé Auteurs : Madhvanand N. Kashid, Auteur ; Lioubov Kiwi-Minsker, Auteur Année de publication : 2009 Article en page(s) : pp. 6465–6485 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Microstructured  reactors  Multiphase  reactions Résumé : The manufacture of chemicals in microstructured reactors (MSR) has become recently a new branch of chemical reaction engineering focusing on process intensification and safety. MSR have an equivalent hydraulic diameter up to a few hundreds of micrometers and, therefore, provide high mass- and heat-transfer efficiency increasing the reactor performance drastically, compared to the conventional one. This article provides a comprehensive overview of the state of the art of the MSR applied for multiphase reactions. The reactions are classified based on the number of phases involved: fluid−fluid, fluid−solid, and three phase reactions. In the first part of the review, limitations of conventional reactors are discussed in brief. Furthermore, different types of MSR and their advantages with respect to their conventional counterparts are described. Particular attention is given to the identification of the parameters that control the flow pattern formed in microcapillaries regarding the mass-transfer efficiency. Case studies of various multiphase reactions carried out in MSR are discussed in detail. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017912 [article] Microstructured reactors for multiphase reactions : state of the art [texte imprimé] / Madhvanand N. Kashid, Auteur ; Lioubov Kiwi-Minsker, Auteur . - 2009 . - pp. 6465–6485. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 14 (Juillet 2009) . - pp. 6465–6485 Mots-clés : Microstructured  reactors  Multiphase  reactions Résumé : The manufacture of chemicals in microstructured reactors (MSR) has become recently a new branch of chemical reaction engineering focusing on process intensification and safety. MSR have an equivalent hydraulic diameter up to a few hundreds of micrometers and, therefore, provide high mass- and heat-transfer efficiency increasing the reactor performance drastically, compared to the conventional one. This article provides a comprehensive overview of the state of the art of the MSR applied for multiphase reactions. The reactions are classified based on the number of phases involved: fluid−fluid, fluid−solid, and three phase reactions. In the first part of the review, limitations of conventional reactors are discussed in brief. Furthermore, different types of MSR and their advantages with respect to their conventional counterparts are described. Particular attention is given to the identification of the parameters that control the flow pattern formed in microcapillaries regarding the mass-transfer efficiency. Case studies of various multiphase reactions carried out in MSR are discussed in detail. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8017912