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Characterization of Ti-ZSM-5 prepared by isomorphous substitution of B-ZSM-5 with TiCl4 and its performance in the hydroxylation of phenol / Jian Gao in Industrial & engineering chemistry research, Vol. 49 N° 5 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2194–2199 Titre : Characterization of Ti-ZSM-5 prepared by isomorphous substitution of B-ZSM-5 with TiCl4 and its performance in the hydroxylation of phenol Type de document : texte imprimé Auteurs : Jian Gao, Auteur ; Liu, Min, Auteur ; Xiangsheng Wang, Auteur Année de publication : 2010 Article en page(s) : pp. 2194–2199 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Ti-ZSM-5;  B-ZSM-5;  Isomorphous  substitution Résumé : Ti-ZSM-5 has attracted much attention for its unique catalytic properties in selective oxidation. Isomorphous substitution is an alternative synthesis method to obtain Ti-ZSM-5 with low contents of extraframework Ti. However, the nature of the precursor also has a great influence on the catalytic performance of Ti-ZSM-5. In this work, two Ti-ZSM-5 samples were prepared by isomorphous substitution of precursor B-ZSM-5 zeolites with gaseous TiCl4. The effect of the nature of the B-ZSM-5 precursor obtained by different hydrothermal synthesis procedures on the catalytic performance was investigated through characterization by XRD; FT-IR, UV−vis, and UV−Raman spectroscopies; SEM; N2 adsorption; and phenol hydroxylation. The characterization results show that the two Ti-ZSM-5 samples synthesized by gas−solid isomorphous substitution of the B-ZSM-5 precursor contain very little anatase and have similar amounts of active sites. They consist of cuboidlike crystals with different sizes that are agglomerated into different sizes of spherelike particles. Phenol hydroxylation with dilute H2O2 showed that, because of the smaller crystal size of its cuboid particles, Ti-ZSM-5 synthesized with B-ZSM-5 as the precursor at lower crystallization temperature had better catalytic performance and better recyclability. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901360y [article] Characterization of Ti-ZSM-5 prepared by isomorphous substitution of B-ZSM-5 with TiCl4 and its performance in the hydroxylation of phenol [texte imprimé] / Jian Gao, Auteur ; Liu, Min, Auteur ; Xiangsheng Wang, Auteur . - 2010 . - pp. 2194–2199. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2194–2199 Mots-clés : Ti-ZSM-5;  B-ZSM-5;  Isomorphous  substitution Résumé : Ti-ZSM-5 has attracted much attention for its unique catalytic properties in selective oxidation. Isomorphous substitution is an alternative synthesis method to obtain Ti-ZSM-5 with low contents of extraframework Ti. However, the nature of the precursor also has a great influence on the catalytic performance of Ti-ZSM-5. In this work, two Ti-ZSM-5 samples were prepared by isomorphous substitution of precursor B-ZSM-5 zeolites with gaseous TiCl4. The effect of the nature of the B-ZSM-5 precursor obtained by different hydrothermal synthesis procedures on the catalytic performance was investigated through characterization by XRD; FT-IR, UV−vis, and UV−Raman spectroscopies; SEM; N2 adsorption; and phenol hydroxylation. The characterization results show that the two Ti-ZSM-5 samples synthesized by gas−solid isomorphous substitution of the B-ZSM-5 precursor contain very little anatase and have similar amounts of active sites. They consist of cuboidlike crystals with different sizes that are agglomerated into different sizes of spherelike particles. Phenol hydroxylation with dilute H2O2 showed that, because of the smaller crystal size of its cuboid particles, Ti-ZSM-5 synthesized with B-ZSM-5 as the precursor at lower crystallization temperature had better catalytic performance and better recyclability. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901360y

Thermal unfolding of a double-domain protein / Ying Ren in Industrial & engineering chemistry research, Vol. 48 N° 19 (Octobre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 19 (Octobre 2009) . - pp. 8865–8871 Titre : Thermal unfolding of a double-domain protein : molecular dynamics simulation of rhodanese Type de document : texte imprimé Auteurs : Ying Ren, Auteur ; Jian Gao, Auteur ; Wei Ge, Auteur Année de publication : 2009 Article en page(s) : pp. 8865–8871 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Bovine  liver  rhodanese  Explicit  solvent  molecular  dynamics  simulations Résumé : The thermal unfolding process of bovine liver rhodanese, composing two globular domains (N-domain and C-domain) with similar tertiary structures, has been studied by explicit solvent molecular dynamics (MD) simulations at high temperatures of 450 and 500 K, as well as 308 K for comparisons. The results are in good agreement with the available experimental results (Horowitz, P. M.; Butler, M. Interactive Intermediates Are Formed During the Urea Unfolding of Rhodanese. J. Biol. Chem. 1993, 268 (4), 2500−2504. Shibatani, T.; Kramer, G.; Hardesty, B.; Horowitz, P. M. Domain Separation Precedes Global Unfolding of Rhodanese. J. Biol. Chem. 1999, 274 (47), 33795−33799. Ybarra, J.; Bhattacharyya, A. M.; Panda, M.; Horowitz, P. M. Active Rhodanese Lacking Nonessential Sulfhydryl Groups Contains an Unstable C-Terminal Domain and Can Be Bound, Inactivated, and Reactivated by GroEL. J. Biol. Chem. 2003, 278 (3), 1693−1699). Besides that our simulation can also depict more dynamic details of the unfolding process. The solvent accessible surface area (SASA) shows a remarkable increase mainly due to a more exposed hydrophobic area, indicating that the hydrophobic interaction is considerably weaker at high temperatures. Comparisons between the thermal stabilities of equivalent secondary structures in both domains suggest that the C-domain is more fragile than the N-domain and the breaking down of the secondary structures follows the pattern [α-helix]→[bend, turn, 3-helix, and 5-helix]. Different regimes of unfolding intermediates have also been discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801441x [article] Thermal unfolding of a double-domain protein : molecular dynamics simulation of rhodanese [texte imprimé] / Ying Ren, Auteur ; Jian Gao, Auteur ; Wei Ge, Auteur . - 2009 . - pp. 8865–8871. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 19 (Octobre 2009) . - pp. 8865–8871 Mots-clés : Bovine  liver  rhodanese  Explicit  solvent  molecular  dynamics  simulations Résumé : The thermal unfolding process of bovine liver rhodanese, composing two globular domains (N-domain and C-domain) with similar tertiary structures, has been studied by explicit solvent molecular dynamics (MD) simulations at high temperatures of 450 and 500 K, as well as 308 K for comparisons. The results are in good agreement with the available experimental results (Horowitz, P. M.; Butler, M. Interactive Intermediates Are Formed During the Urea Unfolding of Rhodanese. J. Biol. Chem. 1993, 268 (4), 2500−2504. Shibatani, T.; Kramer, G.; Hardesty, B.; Horowitz, P. M. Domain Separation Precedes Global Unfolding of Rhodanese. J. Biol. Chem. 1999, 274 (47), 33795−33799. Ybarra, J.; Bhattacharyya, A. M.; Panda, M.; Horowitz, P. M. Active Rhodanese Lacking Nonessential Sulfhydryl Groups Contains an Unstable C-Terminal Domain and Can Be Bound, Inactivated, and Reactivated by GroEL. J. Biol. Chem. 2003, 278 (3), 1693−1699). Besides that our simulation can also depict more dynamic details of the unfolding process. The solvent accessible surface area (SASA) shows a remarkable increase mainly due to a more exposed hydrophobic area, indicating that the hydrophobic interaction is considerably weaker at high temperatures. Comparisons between the thermal stabilities of equivalent secondary structures in both domains suggest that the C-domain is more fragile than the N-domain and the breaking down of the secondary structures follows the pattern [α-helix]→[bend, turn, 3-helix, and 5-helix]. Different regimes of unfolding intermediates have also been discussed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie801441x