Boron Oxide Production Kinetics Using Boric Acid as Raw Material / Suna Balci in Industrial & engineering chemistry research, Vol. 51 N° 34 (Août 2012)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 51 N° 34 (Août 2012) . - pp. 11091-11096 Titre : Boron Oxide Production Kinetics Using Boric Acid as Raw Material Type de document : texte imprimé Auteurs : Suna Balci, Auteur ; Naime Asli Sezgi, Auteur ; Esin Eren, Auteur Année de publication : 2012 Article en page(s) : pp. 11091-11096 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Raw materials Kinetics Production Résumé : Boron oxide with a content of 99.93 wt.% from the dehydration of boric acid was synthesized. Conversion of boric acid to boron oxide was completed within 3 days at low temperature range (T 130 °C) for the isothermal dehydration reaction in the temperature range of 80 and 350 °C. Apparent activation energies were 65 and 28 kJ·mol―1 for low and high temperature ranges, respectively. Thermogravimetric analysis (TGA) results showed that the reactions were nearly completed at around 330 °C, and activation energy for the first temperature region was found to be two-thirds of the isothermal value and the same for the second temperature region. Isothermal data analysis revealed that the apparent reaction order value was around 1.0 at low temperature range and decreased to 0.55 with temperature within the high temperature range. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26299433 [article] Boron Oxide Production Kinetics Using Boric Acid as Raw Material [texte imprimé] / Suna Balci, Auteur ; Naime Asli Sezgi, Auteur ; Esin Eren, Auteur . - 2012 . - pp. 11091-11096. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 34 (Août 2012) . - pp. 11091-11096 Mots-clés : Raw materials Kinetics Production Résumé : Boron oxide with a content of 99.93 wt.% from the dehydration of boric acid was synthesized. Conversion of boric acid to boron oxide was completed within 3 days at low temperature range (T 130 °C) for the isothermal dehydration reaction in the temperature range of 80 and 350 °C. Apparent activation energies were 65 and 28 kJ·mol―1 for low and high temperature ranges, respectively. Thermogravimetric analysis (TGA) results showed that the reactions were nearly completed at around 330 °C, and activation energy for the first temperature region was found to be two-thirds of the isothermal value and the same for the second temperature region. Isothermal data analysis revealed that the apparent reaction order value was around 1.0 at low temperature range and decreased to 0.55 with temperature within the high temperature range. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26299433

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Nafion-incorporated silicate structured nanocomposite mesoporous catalysts for dimethyl ether synthesis / Aysegul Ciftci in Industrial & engineering chemistry research, Vol. 49 N° 15 (Août 2010)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6753–6762 Titre : Nafion-incorporated silicate structured nanocomposite mesoporous catalysts for dimethyl ether synthesis Type de document : texte imprimé Auteurs : Aysegul Ciftci, Auteur ; Naime Asli Sezgi, Auteur ; Timur Dogu, Auteur Année de publication : 2010 Article en page(s) : pp 6753–6762 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Mesoporous Catalysts Ether synthesis. Résumé : Being chemically and thermally stable, Nafion resin is considered to be an attractive solid acid catalyst. Although it has high acid strength and the ability to catalyze a wide range of reactions, the catalytic activity of Nafion is limited, because of its very low specific surface area. In this study, mesoporous Nafion−silica nanocomposites were developed by following a one-pot acidic hydrothermal synthesis procedure. Synthesized catalysts were determined to have well-dispersed structures with high surface area values (595−792 m2/g) and strong Brønsted, as well as Lewis, acid sites. The activities of these novel catalysts were tested in dimethyl ether synthesis from methanol in a flow system. The effects of modifications in the synthesis procedure and Nafion loading showed that the material synthesized from a solution containing a Nafion/silica weight ratio of 0.15 and refluxed with a 2 M sulfuric acid−ethanol (SAE) mixture for surfactant removal was the best catalyst for this reaction. Production of the green transportation fuel alternate dimethyl ether (DME) was achieved with this catalyst at very high yields with almost 100% DME selectivity at >180 °C. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9015667 [article] Nafion-incorporated silicate structured nanocomposite mesoporous catalysts for dimethyl ether synthesis [texte imprimé] / Aysegul Ciftci, Auteur ; Naime Asli Sezgi, Auteur ; Timur Dogu, Auteur . - 2010 . - pp 6753–6762. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 15 (Août 2010) . - pp 6753–6762 Mots-clés : Mesoporous Catalysts Ether synthesis. Résumé : Being chemically and thermally stable, Nafion resin is considered to be an attractive solid acid catalyst. Although it has high acid strength and the ability to catalyze a wide range of reactions, the catalytic activity of Nafion is limited, because of its very low specific surface area. In this study, mesoporous Nafion−silica nanocomposites were developed by following a one-pot acidic hydrothermal synthesis procedure. Synthesized catalysts were determined to have well-dispersed structures with high surface area values (595−792 m2/g) and strong Brønsted, as well as Lewis, acid sites. The activities of these novel catalysts were tested in dimethyl ether synthesis from methanol in a flow system. The effects of modifications in the synthesis procedure and Nafion loading showed that the material synthesized from a solution containing a Nafion/silica weight ratio of 0.15 and refluxed with a 2 M sulfuric acid−ethanol (SAE) mixture for surfactant removal was the best catalyst for this reaction. Production of the green transportation fuel alternate dimethyl ether (DME) was achieved with this catalyst at very high yields with almost 100% DME selectivity at >180 °C. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9015667

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