Documents disponibles écrits par cet auteur

Application of preferential crystallization for different types of racemic compounds / Yinghong Lu in Industrial & engineering chemistry research, Vol. 48 N° 15 (Août 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 15 (Août 2009) . - pp. 7266–7275 Titre : Application of preferential crystallization for different types of racemic compounds Type de document : texte imprimé Auteurs : Yinghong Lu, Auteur ; Xiujuan Wang, Auteur ; Chi Bun Ching, Auteur Année de publication : 2009 Article en page(s) : pp. 7266–7275 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Preferential  crystallization  Racemic-conglomerate-forming  system  Systematic  approach Résumé : A systematic approach was developed and applied to the preferential crystallization of a racemic-conglomerate-forming system in our previous work. In this work, we extended and modified the strategy for two typical types of racemic-compound-forming systems, namely, mandelic acid and ketoprofen, taking into account the crucial different thermodynamics and crystal structure properties between a racemic compound and a conglomerate. System thermodynamic aspects such as binary melting-point phase diagram and ternary solubility phase diagram were measured. The metastable zone widths of mandelic acid with different compositions in water under different cooling rates were determined with a Lasentec focused beam reflectance (FBR) probe. The crystal nucleation and growth kinetics were measured by s-plane analysis. Based on the solubility and the metastable zone width diagram, the maximum limits of practicable operating ranges for conducting preferential crystallization to obtain enantiomerically pure products was defined. Different operating profiles were applied, and the solution supersaturation was analyzed for the crystallization processes. The optical purities, yields, and crystal size distributions of the final products were examined and compared. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801344s [article] Application of preferential crystallization for different types of racemic compounds [texte imprimé] / Yinghong Lu, Auteur ; Xiujuan Wang, Auteur ; Chi Bun Ching, Auteur . - 2009 . - pp. 7266–7275. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 15 (Août 2009) . - pp. 7266–7275 Mots-clés : Preferential  crystallization  Racemic-conglomerate-forming  system  Systematic  approach Résumé : A systematic approach was developed and applied to the preferential crystallization of a racemic-conglomerate-forming system in our previous work. In this work, we extended and modified the strategy for two typical types of racemic-compound-forming systems, namely, mandelic acid and ketoprofen, taking into account the crucial different thermodynamics and crystal structure properties between a racemic compound and a conglomerate. System thermodynamic aspects such as binary melting-point phase diagram and ternary solubility phase diagram were measured. The metastable zone widths of mandelic acid with different compositions in water under different cooling rates were determined with a Lasentec focused beam reflectance (FBR) probe. The crystal nucleation and growth kinetics were measured by s-plane analysis. Based on the solubility and the metastable zone width diagram, the maximum limits of practicable operating ranges for conducting preferential crystallization to obtain enantiomerically pure products was defined. Different operating profiles were applied, and the solution supersaturation was analyzed for the crystallization processes. The optical purities, yields, and crystal size distributions of the final products were examined and compared. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801344s

How Is effective enantioselectivity of immobilized enzyme in kinetic resolution of racemate affected in a fixed-bed reactor? / Hongwei Yu ; Chi Bun Ching in Industrial & engineering chemistry research, Vol. 47 n°22 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8808–8814 Titre : How Is effective enantioselectivity of immobilized enzyme in kinetic resolution of racemate affected in a fixed-bed reactor? Type de document : texte imprimé Auteurs : Hongwei Yu, Auteur ; Chi Bun Ching, Auteur Année de publication : 2008 Article en page(s) : p. 8808–8814 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Enantioselectivity Résumé : The purpose of this theoretical discussion is to help researchers understand how some parameters and reaction type (first-order and Michaelis−Menten kinetic) could impact effective enantioselectivity of enzyme in a fixed-bed reactor, including adsorption equilibrium constant (adsorption effect), Biot number, Peclet number, and bed length parameter. The theoretical analysis clearly derives that reaction rate is able to impact the effective enantioselectivity of enzyme through controlling the loading of enzyme on the solid support. In addition, adsorption phenomenon and reaction type have no effect on the effective enantioselectivity in a fixed-bed reactor. Among these parameters, Bi (<10) shows significant effect on the effective enantioselectivity, which indicates that external mass transfer limitation must be controlled. The interesting analysis suggests that cross-link enzyme aggregates without carrier could be an optional way to overcome mass transfer limitation for immobilized enzyme, and if solid support is applied, adsorption method, which is able to facilitate substrates to contact with enzyme compared to other immobilization methods, could be the best choice to immobilize enzyme when the kinetic resolution of racemate is conducted in a fixed-bed reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800429e [article] How Is effective enantioselectivity of immobilized enzyme in kinetic resolution of racemate affected in a fixed-bed reactor? [texte imprimé] / Hongwei Yu, Auteur ; Chi Bun Ching, Auteur . - 2008 . - p. 8808–8814. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°22 (Novembre 2008) . - p. 8808–8814 Mots-clés : Enantioselectivity Résumé : The purpose of this theoretical discussion is to help researchers understand how some parameters and reaction type (first-order and Michaelis−Menten kinetic) could impact effective enantioselectivity of enzyme in a fixed-bed reactor, including adsorption equilibrium constant (adsorption effect), Biot number, Peclet number, and bed length parameter. The theoretical analysis clearly derives that reaction rate is able to impact the effective enantioselectivity of enzyme through controlling the loading of enzyme on the solid support. In addition, adsorption phenomenon and reaction type have no effect on the effective enantioselectivity in a fixed-bed reactor. Among these parameters, Bi (<10) shows significant effect on the effective enantioselectivity, which indicates that external mass transfer limitation must be controlled. The interesting analysis suggests that cross-link enzyme aggregates without carrier could be an optional way to overcome mass transfer limitation for immobilized enzyme, and if solid support is applied, adsorption method, which is able to facilitate substrates to contact with enzyme compared to other immobilization methods, could be the best choice to immobilize enzyme when the kinetic resolution of racemate is conducted in a fixed-bed reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800429e

Theoretical analysis of the adsorption effect on kinetic resolution of racemates catalyzed by immobilized enzymes in a batch reactor / Hongwei Yu in Industrial & engineering chemistry research, Vol. 47 n°12 (Juin 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°12 (Juin 2008) . - p. 4251–4255 Titre : Theoretical analysis of the adsorption effect on kinetic resolution of racemates catalyzed by immobilized enzymes in a batch reactor Type de document : texte imprimé Auteurs : Hongwei Yu, Auteur ; Chi Bun Ching, Auteur Année de publication : 2008 Article en page(s) : p. 4251–4255 Note générale : Bibliogr. p. 4255 Langues : Anglais (eng) Mots-clés : Adsorption;  Kinetic  resolution;  Racemate  catalyzed Résumé : Adsorption, a typical physical phenomenon, always neglected in the kinetic resolution of the racemate catalyzed by enzymes immobilized on the porous solid support, was theoretically analyzed. A concept that the adsorption effect plays an important role to affect the superficial performance of the enzyme which is often applied to evaluate the performance of the enzyme was described. Adsorption intensity, or so-called mass equilibrium constant (K), is the most important factor to affect the performance of the enzyme compared with adsorption rate coefficient (k) and adsorption equilibrium (adsorption isotherm) if the solid support with chiral selectivity is applied. The conclusion can be drawn that the solid support with a weak adsorption effect on the racemate may favorite the enzyme to exhibit a good performance in the kinetic resolution of the racemate. The adsorption phenomenon should be considered as an explanation to the performance changing of the enzyme after immobilized. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071300t [article] Theoretical analysis of the adsorption effect on kinetic resolution of racemates catalyzed by immobilized enzymes in a batch reactor [texte imprimé] / Hongwei Yu, Auteur ; Chi Bun Ching, Auteur . - 2008 . - p. 4251–4255. Bibliogr. p. 4255 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°12 (Juin 2008) . - p. 4251–4255 Mots-clés : Adsorption;  Kinetic  resolution;  Racemate  catalyzed Résumé : Adsorption, a typical physical phenomenon, always neglected in the kinetic resolution of the racemate catalyzed by enzymes immobilized on the porous solid support, was theoretically analyzed. A concept that the adsorption effect plays an important role to affect the superficial performance of the enzyme which is often applied to evaluate the performance of the enzyme was described. Adsorption intensity, or so-called mass equilibrium constant (K), is the most important factor to affect the performance of the enzyme compared with adsorption rate coefficient (k) and adsorption equilibrium (adsorption isotherm) if the solid support with chiral selectivity is applied. The conclusion can be drawn that the solid support with a weak adsorption effect on the racemate may favorite the enzyme to exhibit a good performance in the kinetic resolution of the racemate. The adsorption phenomenon should be considered as an explanation to the performance changing of the enzyme after immobilized. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071300t