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] as well as gold catalysts on ceria and ceria–alumina promoted by molybdena [ 18 – 20 ] have shown high activity in the complete oxidation of benzene at low temperatures. The presence of gold particles with high dispersion is a key factor for the high

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(PROX). Nanosized gold particles supported on different metal oxides have been reported as appropriate low temperature (LT) catalysts for these processes. Many studies have been focused on studying gold catalysts on ceria because of its ability to

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knowledge regarding the kinetics of the reaction can still be considered as being limited and incomplete. Studies previously performed over various metal-oxide supported gold catalysts mostly involve power law-type kinetics and reaction orders with

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was extensively used for the preparation of gold catalysts using either sodium hydroxide or urea [ 3 , 4 ], since an alternative method of catalyst preparation by impregnation leads to large gold particles. Although, on a conceptual level, it

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Abstract  

Gold (~1%) has been supported on the mixed oxides Al2O3–CuO–Mn2O3 with molar compositions 1:1:1, 1:0.7:0.3, 1:0.3:0.7, prepared by spray pyrolysis method. The supports and catalysts have been characterized by TG, DTA, N2 physisorption, XRD, SEM, and TEM methods and tested for CO oxidation (25–300 °C). The catalysts revealed high specific surface area and amorphous form for compositions 1:0.7:0.3 and 1:0.3:0.7. Gold deposited on the supports lowered the T 50 values by 50–80 °C. The highest CO conversion was obtained for 1:1:1 composition.

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Reaction Kinetics, Mechanisms and Catalysis
Authors: Iwona Tomska-Foralewska, Wiesław Przystajko, Mariusz Pietrowski, Michał Zieliński, and Maria Wojciechowska

Abstract  

Novel magnesium oxo-fluoride supports containing different amounts of MgO, prepared by the sol–gel method have been proposed for the synthesis of gold catalysts. The MgF2–MgO supports have mesoporous structure and their surface area is a few times larger than those of pure MgF2 or pure MgO. Gold catalysts have been prepared by impregnation of the MgF2–MgO supports with HAuCl4 in the amount corresponding to 1 wt.% Au. The gold catalysts has been characterized by XRD, TEM measurements and the catalytic activity in CO oxidation at temperatures 30–300 °C have been performed. The Au/MgF2–MgO catalysts show higher activities (depending on the content of MgO in the support) as compared to Au/MgF2 and Au/MgO prepared under the same conditions. Their activities fall into the upper range of gold catalysts supported on other carrier reported in literature.

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The oxidation of cyclohexane to cyclohexanone, cyclohexanol, and adipic acid, which are important raw materials in nylon industry, is still being challenged in conventional processes. Microreactors and gold catalysts are both widely researched areas at present, so an effort was made to make use of collaborative properties of both. In this study, stainless steel microcapillary coated with a supported nano-gold catalyst was prepared, characterized, and employed for the oxidation of cyclohexane. Under the temperature of 180 °C, residence time of 4 min, reaction pressure of 3 MPa and molar ratio of oxygen to cyclohexane of 0.3:1, the conversion of cyclohexane was 2.09%, with the selectivity of cyclohexanol, 29.37%; cyclohexanone, 39.89%; cyclohexyl hydroperoxide, 2.46%; and adipic acid, 18.87%. Experiments showed that stainless steel microcapillary coated with a supported nano-gold catalyst in cyclohexane oxidation is a feasible process; the reaction time is very short, and the process operation runs safely.

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preferentially reduced in the presence of the C=O group, which has been demonstrated by kinetic and thermodynamic considerations [ 1 ]. Supported gold catalysts can show very high selectivity to the unsaturated alcohols in the hydrogenation of α

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attracted increasing interest since Haruta et al. [ 2 ] reported that CO oxidation could be achieved at room temperature over gold catalysts when very small gold nanoparticles were dispersed on suitable oxide supports. So far, the catalytic activity of gold

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Acta Alimentaria
Authors: R.V Salamon, É. Vargáné-Visi, Cs.D. András, Zs. Csapóné Kiss, and J. Csapó

linoleic acid to conjugated linoleic acid using gold catalyst . Chem. Engng Technol ., 32 , 2005 – 2010 . B ernas , A. , K umar , N. , M aki -A rvela , P. , H olmbom , B. , S almi , T. & M

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