results are in agreement with acidity data reported in literatures for Al-HMS materials [ 9 ]. The type of acid sites (Lewis acid and Br⊘nsted acid) were also studied by the FT-IR spectra of pyridine adsorption. It is well known that the vibration bands in
Authors:Iwona Tomska-Foralewska, Wiesław Przystajko, Mariusz Pietrowski, Michał Zieliński, and Maria Wojciechowska
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.
This work describes the experimental determination of sucrose hydrolysis kinetics using a heterogeneous catalyst. We used
an Amberlite IR-120 strong acidic cation-exchange resin. The experiments were performed under previously determined optimal
process conditions: sucrose mass concentration, γS = 50 g L−1, catalyst mass concentration, γC = 180 g L−1, rotational frequency of the stirrer fm = 180 min−1, and temperature ϑ = 79 °C. The parameters of the supposed kinetic model were determined using experimental data. The kinetics
of sucrose hydrolysis over Amberlite IR-120 has not been reported to date. Therefore, we could not directly compare the calculated
values of kinetic parameters with those from the literature. However, the calculated values are within the range of values
determined by other types of catalysts. Furthermore, we investigated the influence of catalyst mass concentration γC on the reaction rate constant k′.
Authors:Saet Byul Kim, Mi Ran Lee, Eun Duck Park, Sang Min Lee, HyoKyu Lee, Ki Hyun Park, and Myung-June Park
A kinetic model of the homogeneous conversion of d-xylose in high temperature water (HTW) was developed. Experimental testing evaluated the effects of operating conditions on xylose conversion and furfural selectivity, with furfural yields of up to 60% observed without the use of acid catalysts. The reaction order for the decomposition of d-xylose was assumed to be above two, while the conversion of d-xylose to furfural and the degradation of furfural were first order reactions. Estimated kinetic parameters were within the range of values reported in the literature. The activation energy of furfural production showed that the ionization rate was high enough for HTW to replace acid catalysts. Simulated results from this model were in good agreement with experimental data, allowing the model to aid reactor design for the maximization of productivity.
Authors:Haruka Seki, Masa-aki Ohshima, Hideki Kurokawa, and Hiroshi Miura
The influence of trace oxygen on the catalytic activity of alumina supported Ru in the liquid phase hydrogenation of aromatic
hydrocarbons was studied. The catalytic activity of Ru increased remarkably and the reproducibility was improved by removing
dissolved oxygen from the reactant mixture and carefully refining the catalyst transfer procedure into the reactor to avoid
exposure to air. Trace oxygen affected Ru very severely, but did not affect Rh, Pd, and Pt much. The activity of Ru was lower
than those of Rh, Pd, and Pt in the presence of oxygen as reported in the literature; however, it was the highest when oxygen
was removed carefully. Measurements of the adsorbed oxygen suggested that the activity seriously decreased when only the part
of Ru surface was covered by oxygen. Bimetallic Pt–Ru catalysts demonstrated high activity even in the presence of oxygen.
Authors:Cristina Benincá, Patrício Peralta-Zamora, Ronaldo Cardoso Camargo, Célia Regina Granhen Tavares, Everton Fernando Zanoelo, and Luciana Igarashi-Mafra
extensive application, studies of its degradation by involving advanced oxidative processes are limited in the literature [ 18 – 20 ], and even nonexistent when applying Fenton and photo-Fenton procedures.
Authors:C. Amairia, S. Fessi, A. Ghorbel, and A. Rîves
oxidation of methane at low temperature have been extensively studied so far [ 9 – 14 ]. In particular, palladium-based systems have been widely reported in literature as the catalyst of choice in methane combustion [ 15 , 16 ]. Some properties of these
a concentrated alkaline solution [ 1 – 4 ]. They provided very good catalytic performances in comparison with other catalysts reported in the literature [ 5 ], and also provide the lowest cost per unit mass of catalyst combined with a high activity
Authors:Luděk Kaluža, Zdeněk Vít, and Miroslav Zdražil
literature. The effect of support on the conventional CoMo and NiMo catalysts was reviewed by Luck [ 1 ] and Breysse et al. [ 2 ].
Sulfides of noble metals (Pt, Rh, Pd, Ru and Ir) exhibit high activity and were the subject of extensive research. Rh