Documents disponibles écrits par cet auteur

Integration of microreactors with spectroscopic detection for online reaction monitoring and catalyst characterization / Jun Yue in Industrial & engineering chemistry research, Vol. 51 N° 45 (Novembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 45 (Novembre 2012) . - pp 14583–14609 Titre : Integration of microreactors with spectroscopic detection for online reaction monitoring and catalyst characterization Type de document : texte imprimé Auteurs : Jun Yue, Auteur ; Jaap C. Schouten, Auteur ; T. Alexander Nijhuis, Auteur Année de publication : 2013 Article en page(s) : pp 14583–14609 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Microreactors  Catalyst Résumé : Microreactor technology has gained significant popularity in the chemical and process industry in the past decade. The development of microreactors either as innovative production units for chemical synthesis or as promising laboratory tools for reaction and kinetic studies relies highly on the capability of performing online analyses, which opens great opportunities for the integration of spectroscopic detection techniques. This paper gives an overview of the state-of-the-art in the combination of microreactors with spectroscopic analyses for online reaction monitoring and catalyst characterization. In this upcoming field, many studies have been carried out combining fluorescence, ultraviolet–visible, infrared, Raman, X-ray, and nuclear magnetic resonance spectroscopy. Current research progress is reviewed, with emphasis on the existing integration schemes and selected application examples that demonstrate the potential of online spectroscopic detection for rapid microreactor process analysis and optimization. An outlook on the future development in this area is also presented. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301258j [article] Integration of microreactors with spectroscopic detection for online reaction monitoring and catalyst characterization [texte imprimé] / Jun Yue, Auteur ; Jaap C. Schouten, Auteur ; T. Alexander Nijhuis, Auteur . - 2013 . - pp 14583–14609. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 45 (Novembre 2012) . - pp 14583–14609 Mots-clés : Microreactors  Catalyst Résumé : Microreactor technology has gained significant popularity in the chemical and process industry in the past decade. The development of microreactors either as innovative production units for chemical synthesis or as promising laboratory tools for reaction and kinetic studies relies highly on the capability of performing online analyses, which opens great opportunities for the integration of spectroscopic detection techniques. This paper gives an overview of the state-of-the-art in the combination of microreactors with spectroscopic analyses for online reaction monitoring and catalyst characterization. In this upcoming field, many studies have been carried out combining fluorescence, ultraviolet–visible, infrared, Raman, X-ray, and nuclear magnetic resonance spectroscopy. Current research progress is reviewed, with emphasis on the existing integration schemes and selected application examples that demonstrate the potential of online spectroscopic detection for rapid microreactor process analysis and optimization. An outlook on the future development in this area is also presented. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie301258j

Rotating foam stirrer reactor / Maria A. Leon in Industrial & engineering chemistry research, Vol. 50 N° 6 (Mars 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3184–3193 Titre : Rotating foam stirrer reactor : effect of catalyst coating characteristics on reactor performance Type de document : texte imprimé Auteurs : Maria A. Leon, Auteur ; Roman Tschentscher, Auteur ; T. Alexander Nijhuis, Auteur Année de publication : 2011 Article en page(s) : pp. 3184–3193 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Catalyst Résumé : Rotating foam stirrer reactors have a promising application in multiphase reactions. In this reactor, highly porous open-celled materials, solid foams, are used both as a catalyst support and as stirrer blades. One of the advantages of such a foam stirrer is easy catalyst handling. This paper presents a preparation method for catalysts on solid foam supports. The performance of the alumina foam catalysts is tested in the hydrogenation of a functionalized alkyne. A stable and homogeneous catalytic coating was deposited on aluminum foams by a combination of anodization and wash coating using the slurry method. Anodization produced a rough and porous material that improved the adhesion of the catalytic coating. The use of a slurry with a bimodal particle size distribution increased the catalytic coating stability. The mass loss of the catalytic coating after applying ultrasonic vibrations was less than 10 wt %, which indicates a good adhesion. A high specific surface area was achieved by increasing the foam cell density, that is, the number of pores per linear inch (ppi), and the catalytic coating thickness. With the wash-coating method, catalytic coatings were produced having a thickness between 10 and 40 μm, a porosity of around 50%, and a specific surface area up to 28.5 m2/gfoam. The hydrogenation of 3-methyl-1-pentyn-3-ol was chosen as the test reaction. Internal and external mass transfers limit the reaction rate of this fast reaction. High activity and selectivity were reached by combining a high specific surface area with a thin catalytic coating on the foam. Increasing the foam cell density up to 20 ppi led to enhanced liquid−solid mass transfer because of the high specific surface area combined with the fast refreshment of the catalyst surface. Coating thicknesses of less than 20 μm led to improved internal mass transfer due to shorter diffusion paths. DEWEY : 6600 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101962g [article] Rotating foam stirrer reactor : effect of catalyst coating characteristics on reactor performance [texte imprimé] / Maria A. Leon, Auteur ; Roman Tschentscher, Auteur ; T. Alexander Nijhuis, Auteur . - 2011 . - pp. 3184–3193. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3184–3193 Mots-clés : Catalyst Résumé : Rotating foam stirrer reactors have a promising application in multiphase reactions. In this reactor, highly porous open-celled materials, solid foams, are used both as a catalyst support and as stirrer blades. One of the advantages of such a foam stirrer is easy catalyst handling. This paper presents a preparation method for catalysts on solid foam supports. The performance of the alumina foam catalysts is tested in the hydrogenation of a functionalized alkyne. A stable and homogeneous catalytic coating was deposited on aluminum foams by a combination of anodization and wash coating using the slurry method. Anodization produced a rough and porous material that improved the adhesion of the catalytic coating. The use of a slurry with a bimodal particle size distribution increased the catalytic coating stability. The mass loss of the catalytic coating after applying ultrasonic vibrations was less than 10 wt %, which indicates a good adhesion. A high specific surface area was achieved by increasing the foam cell density, that is, the number of pores per linear inch (ppi), and the catalytic coating thickness. With the wash-coating method, catalytic coatings were produced having a thickness between 10 and 40 μm, a porosity of around 50%, and a specific surface area up to 28.5 m2/gfoam. The hydrogenation of 3-methyl-1-pentyn-3-ol was chosen as the test reaction. Internal and external mass transfers limit the reaction rate of this fast reaction. High activity and selectivity were reached by combining a high specific surface area with a thin catalytic coating on the foam. Increasing the foam cell density up to 20 ppi led to enhanced liquid−solid mass transfer because of the high specific surface area combined with the fast refreshment of the catalyst surface. Coating thicknesses of less than 20 μm led to improved internal mass transfer due to shorter diffusion paths. DEWEY : 6600 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101962g

The direct epoxidation of propene in the explosive regime in a microreactor — a study into the reaction kinetics / T. Alexander Nijhuis in Industrial & engineering chemistry research, Vol. 49 N° 21 (Novembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10479–10485 Titre : The direct epoxidation of propene in the explosive regime in a microreactor — a study into the reaction kinetics Type de document : texte imprimé Auteurs : T. Alexander Nijhuis, Auteur ; Jiaqi Chen, Auteur ; Stefanie M. A. Kriescher, Auteur Année de publication : 2011 Article en page(s) : pp. 10479–10485 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Microreactor  Kinetics Résumé : The usage of a microreactor system for the direct epoxidation of propene over a gold-titania-based catalyst system using a mixture of hydrogen, oxygen, and propene allows for the safe operation of the reaction in the explosive regime. A kinetic study was performed on the effect of the concentration of hydrogen, oxygen, and propene on the reaction rate as well as the catalyst deactivation and reactivation. A simple algebraic expression was developed, based on published kinetics, which provided the three reaction rate constants as a function of the feed gas concentrations. It is shown that the propene concentration does not influence the propene oxide formation rate; however, higher propene concentrations significantly reduce the catalyst deactivation rate. Hydrogen increases the rate of the epoxidation reaction, while it only has a minor influence on the rate of deactivation and reactivation. Oxygen has a beneficial effect on the epoxidation reaction: it slightly decreases the deactivation rate and is beneficial for the catalyst reactivation. It is shown that, for the gold on titania dispersed on a silica catalyst used in this study, it is advantageous to perform the direct propene epoxidation in a microreactor system at the highest possible feed concentrations for each of the reactants. This results in the highest propene oxide productivity and the lowest deactivation rate. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1004306 [article] The direct epoxidation of propene in the explosive regime in a microreactor — a study into the reaction kinetics [texte imprimé] / T. Alexander Nijhuis, Auteur ; Jiaqi Chen, Auteur ; Stefanie M. A. Kriescher, Auteur . - 2011 . - pp. 10479–10485. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 21 (Novembre 2010) . - pp. 10479–10485 Mots-clés : Microreactor  Kinetics Résumé : The usage of a microreactor system for the direct epoxidation of propene over a gold-titania-based catalyst system using a mixture of hydrogen, oxygen, and propene allows for the safe operation of the reaction in the explosive regime. A kinetic study was performed on the effect of the concentration of hydrogen, oxygen, and propene on the reaction rate as well as the catalyst deactivation and reactivation. A simple algebraic expression was developed, based on published kinetics, which provided the three reaction rate constants as a function of the feed gas concentrations. It is shown that the propene concentration does not influence the propene oxide formation rate; however, higher propene concentrations significantly reduce the catalyst deactivation rate. Hydrogen increases the rate of the epoxidation reaction, while it only has a minor influence on the rate of deactivation and reactivation. Oxygen has a beneficial effect on the epoxidation reaction: it slightly decreases the deactivation rate and is beneficial for the catalyst reactivation. It is shown that, for the gold on titania dispersed on a silica catalyst used in this study, it is advantageous to perform the direct propene epoxidation in a microreactor system at the highest possible feed concentrations for each of the reactants. This results in the highest propene oxide productivity and the lowest deactivation rate. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie1004306