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Nitration of phenol over a ZSM-5 zeolite / M. Arshadi in Industrial & engineering chemistry research, Vol. 49 N° 12 (Juin 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5504–5510 Titre : Nitration of phenol over a ZSM-5 zeolite Type de document : texte imprimé Auteurs : M. Arshadi, Auteur ; M. Ghiaci, Auteur ; A. Gil, Auteur Année de publication : 2010 Article en page(s) : pp. 5504–5510 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Liquid  phase  nitration  of  phenol  Nitric  acid Résumé : In this paper, liquid phase nitration of phenol over a solid acid catalyst, ZSM-5 zeolite, was investigated by nitric acid (60%) under various solvent and temperature conditions. The performance of the nitration in ortho and para positions of phenol is suggested to derive from the amount of catalyst and the solvent effects. The loading level of the substrate inside or outside the pores of the zeolite makes the relatively high selectivity to the ortho or para product. However, the experimental results are accounted for by the important role of solvent and the amount of ZSM-5 zeolite in ortho/para selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901862q [article] Nitration of phenol over a ZSM-5 zeolite [texte imprimé] / M. Arshadi, Auteur ; M. Ghiaci, Auteur ; A. Gil, Auteur . - 2010 . - pp. 5504–5510. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 12 (Juin 2010) . - pp. 5504–5510 Mots-clés : Liquid  phase  nitration  of  phenol  Nitric  acid Résumé : In this paper, liquid phase nitration of phenol over a solid acid catalyst, ZSM-5 zeolite, was investigated by nitric acid (60%) under various solvent and temperature conditions. The performance of the nitration in ortho and para positions of phenol is suggested to derive from the amount of catalyst and the solvent effects. The loading level of the substrate inside or outside the pores of the zeolite makes the relatively high selectivity to the ortho or para product. However, the experimental results are accounted for by the important role of solvent and the amount of ZSM-5 zeolite in ortho/para selectivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901862q

Structure evolution of Co/alumina-pillared clay catalysts under thermal treatment at increasing temperatures / A. Gil in Industrial & engineering chemistry research, Vol. 47 N°19 (Octobre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°19 (Octobre 2008) . - p. 7226–7235 Titre : Structure evolution of Co/alumina-pillared clay catalysts under thermal treatment at increasing temperatures Type de document : texte imprimé Auteurs : A. Gil, Auteur ; R. Trujillano, Auteur ; M. A. Vicente, Auteur Année de publication : 2008 Article en page(s) : p. 7226–7235 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Thermal  treatment  Co/alumina-pillared  montmorillonite  catalyst  X-ray  diffraction Résumé : The aim of this work is to study the effect of the thermal treatment at 350 and 500 °C on the structure of a Co/alumina-pillared montmorillonite catalyst. For this purpose, the X-ray powder diffraction patterns of the solids, the nitrogen physisorption data at −196 °C, the micropore-size distributions, the UV−vis and NIR spectroscopies of the dried materials, the gravimetric and differential thermal analyses, and the temperature-programmed reduction analyses of the supported cobalt catalysts have been analyzed and compared. The impregnation with cobalt and the temperature has modified the textural properties of the alumina-pillared clay supports, giving rise to a loss of surface area and micropore volume in the final catalysts. Co3O4 is the only cobalt oxide species detected in all the supported catalysts. The oxidation of propene at low concentrations over selected cobalt oxide catalysts shows that the structural characteristics of the support influence on the catalytic performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071320v [article] Structure evolution of Co/alumina-pillared clay catalysts under thermal treatment at increasing temperatures [texte imprimé] / A. Gil, Auteur ; R. Trujillano, Auteur ; M. A. Vicente, Auteur . - 2008 . - p. 7226–7235. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°19 (Octobre 2008) . - p. 7226–7235 Mots-clés : Thermal  treatment  Co/alumina-pillared  montmorillonite  catalyst  X-ray  diffraction Résumé : The aim of this work is to study the effect of the thermal treatment at 350 and 500 °C on the structure of a Co/alumina-pillared montmorillonite catalyst. For this purpose, the X-ray powder diffraction patterns of the solids, the nitrogen physisorption data at −196 °C, the micropore-size distributions, the UV−vis and NIR spectroscopies of the dried materials, the gravimetric and differential thermal analyses, and the temperature-programmed reduction analyses of the supported cobalt catalysts have been analyzed and compared. The impregnation with cobalt and the temperature has modified the textural properties of the alumina-pillared clay supports, giving rise to a loss of surface area and micropore volume in the final catalysts. Co3O4 is the only cobalt oxide species detected in all the supported catalysts. The oxidation of propene at low concentrations over selected cobalt oxide catalysts shows that the structural characteristics of the support influence on the catalytic performance. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie071320v

Synthesis and characterization of Co–Mn nanoparticles immobilized on a modified bentonite and its application for oxidation of p-xylene to terephthalic acid / M. Ghiaci in Industrial & engineering chemistry research, Vol. 51 N° 49 (Décembre 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 49 (Décembre 2012) . - pp. 15821–15831 Titre : Synthesis and characterization of Co–Mn nanoparticles immobilized on a modified bentonite and its application for oxidation of p-xylene to terephthalic acid Type de document : texte imprimé Auteurs : M. Ghiaci, Auteur ; M. Mostajeran, Auteur ; A. Gil, Auteur Année de publication : 2013 Article en page(s) : pp. 15821–15831 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Nanoparticles  Oxidation Résumé : This study describes the synthesis and characterization of a new supported bentonite catalyst prepared by the two-step modification of Na-bentonite. In the first step, Na-bentonite is modified with cetyl pyridinium bromide (CPB) to give a monolayer bentonite (CP-bentonite) in which surfactant ions are adsorbed by cation exchange with the counterions of bentonite. This gives a disordered liquid-like monolayer arrangement of alkyl chains within the gallery. This monolayer bentonite is then treated with the second generation of an amidoamine cascade known as 3,3′-(dodecylazanediyl)bis(N-(2-(2,3,3′-(dodecylazanediyl)bis(N-(2-(2-aminoethyl(2-hydroxybenzenimine))ethyl)propanamide) (DAEP), which has a long aliphatic tail (C12) and a hydrophilic head, to form a modified bilayer bentonite (Ben-DAEP-modified). The solid/liquid interface layer of this architecturally designed bentonite (Ben-DAEP-modified) was used as a pincer-type ligand for the synthesis of a new host–guest catalyst by immobilization of Co, Mn, or Co/Mn on it. The structure, specific surface area, and porosity of bentonite are significantly altered by the incorporation of nanoparticles. The resulting solid catalysts were characterized by UV–vis, Fourier transform infrared (FT-IR), inductively coupled plasma (ICP), scanning electron microscopy (SEM), N2 adsorption, and transmission electron microscopy (TEM) techniques. The oxidation of p-xylene produces five products: 4-methyl benzaldehyde, 4-methyl benzoic acid, 1,4-benzene dialdehyde, 4-carboxybenzaldehyde, and 1,4-benzenedioic acid. The reaction conditions for oxidation of p-xylene were optimized by varying the temperature, pressure, amount of catalyst, time, and catalyst-to-oxidant ratio. The optimum conditions for oxidation of p-xylene to 1,4-benzenedioic acid (terephthalic acid) were 0.15 g of Ben-DAEP-modified-Co/Mn (Co/Mn with a ratio of 10/1), 190 °C, 3% of Br– as promoter, 17 atm, and 3 h. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3021939 [article] Synthesis and characterization of Co–Mn nanoparticles immobilized on a modified bentonite and its application for oxidation of p-xylene to terephthalic acid [texte imprimé] / M. Ghiaci, Auteur ; M. Mostajeran, Auteur ; A. Gil, Auteur . - 2013 . - pp. 15821–15831. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 49 (Décembre 2012) . - pp. 15821–15831 Mots-clés : Nanoparticles  Oxidation Résumé : This study describes the synthesis and characterization of a new supported bentonite catalyst prepared by the two-step modification of Na-bentonite. In the first step, Na-bentonite is modified with cetyl pyridinium bromide (CPB) to give a monolayer bentonite (CP-bentonite) in which surfactant ions are adsorbed by cation exchange with the counterions of bentonite. This gives a disordered liquid-like monolayer arrangement of alkyl chains within the gallery. This monolayer bentonite is then treated with the second generation of an amidoamine cascade known as 3,3′-(dodecylazanediyl)bis(N-(2-(2,3,3′-(dodecylazanediyl)bis(N-(2-(2-aminoethyl(2-hydroxybenzenimine))ethyl)propanamide) (DAEP), which has a long aliphatic tail (C12) and a hydrophilic head, to form a modified bilayer bentonite (Ben-DAEP-modified). The solid/liquid interface layer of this architecturally designed bentonite (Ben-DAEP-modified) was used as a pincer-type ligand for the synthesis of a new host–guest catalyst by immobilization of Co, Mn, or Co/Mn on it. The structure, specific surface area, and porosity of bentonite are significantly altered by the incorporation of nanoparticles. The resulting solid catalysts were characterized by UV–vis, Fourier transform infrared (FT-IR), inductively coupled plasma (ICP), scanning electron microscopy (SEM), N2 adsorption, and transmission electron microscopy (TEM) techniques. The oxidation of p-xylene produces five products: 4-methyl benzaldehyde, 4-methyl benzoic acid, 1,4-benzene dialdehyde, 4-carboxybenzaldehyde, and 1,4-benzenedioic acid. The reaction conditions for oxidation of p-xylene were optimized by varying the temperature, pressure, amount of catalyst, time, and catalyst-to-oxidant ratio. The optimum conditions for oxidation of p-xylene to 1,4-benzenedioic acid (terephthalic acid) were 0.15 g of Ben-DAEP-modified-Co/Mn (Co/Mn with a ratio of 10/1), 190 °C, 3% of Br– as promoter, 17 atm, and 3 h. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie3021939