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metalloporphyrins, could remarkably improve the catalytic activity and selectivity of metalloporphyrins in the alkene oxidation reaction [ 15 , 16 ]. Except for the axial ligands, the metal centers and the substitutional groups around porphyrin rings have a great

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diameter about 5 μm in a ternary P123-H 2 O-HCl-TEOS system were prepared by the hydrothermal method. The physical properties of the prepared Ti-containing SBA-15 samples were investigated and the catalytic activity in the epoxidation of cyclohexene was

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was also evaluated to correlate their porous characteristic and platinum dispersion with catalytic activity. Experimental Preparation of catalysts Four silicas were used in the preparation of platinum

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parameters on the activity of Ru/AC for bromate reduction up to now. In the present work, the effects of Ru precursor, Ru loading and calcination conditions on the catalytic activities of Ru/AC catalyst for bromate reduction were systematically

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A calorimetric method is proposed to evaluate the catalytic activity of a solid catalyst with respect to the exothermic oxidation of Volatile Organic Compounds (VOC).

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Schiff base complexes, Mn(III), Co(II), and Cr(III) complexes have gained prominence because of their catalytic activities for a variety of oxidative organic transformations in the presence of hydrogen peroxide or organic peroxides both in homogeneous and

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expected to improve the catalytic activity and stability [ 7 , 12 ]. For example, manganese (or other promoters such as gallium, yttrium, and lanthanum) was suggested as a promoter to increase the dispersion and reducibility of copper and therefore it

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or phophinites [ 5 , 6 ]. However, there are few reports describing rhodium complexes with amine ligands in biphasic hydroformylation reactions which can be compared and show good performance in their catalytic activity as traditional rhodium with

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Abstract  

Different Nd-zeolites were prepared from the original NaX and NaY zeolites by ion exchange. The hydrated and thermally activated (at 550 °C) samples obtained were irradiated with -rays of 1.5 and 10.0 Mrad. The unirradiated and irradiated samples were characterized mainly by X-ray diffraction and tested for catalytic activity in cumene cracking. The X-ray diffraction patterns indicated a slight decrease of crystallinity after irradiation. However, the irradiated samples exhibited higher catalytic activities than unirradiated ones. -Irradiated hydrated zeolites were found to possess comparable activities, whereas the irradiated dehydrated samples were more active. Higher irradiation doses resulted in more active dehydrated zeolites than those irradiated with a lower dose. The observed higher activity was attributed to the formation of tricoordinate aluminium atoms in the zeolite structure, leading to increase of the number of acidic sites and consequently to a catalytic activity.

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Abstract  

Catalytic activity of gamma irradiated catalase from bovine liver was studied for hydrogen peroxide decomposition at constant temperature and pressure. The measurement was performed at temperatures 27, 32, 37, 42 and 47 °C. Solutions containing 1 and 0.01 g dm−3 of catalase in phosphate buffer were used for the study. Repeatability of both sample preparation and kinetics measurement was experimentally verified. Rate constants of the reaction were determined for all temperatures and the activation energy was evaluated from Arrhenius plot. Gamma irradiation was performed using 60Co radionuclide source Gammacell 220 at two different dose rates 5.5 and 70 Gy h−1, with doses ranging from 10 to 1000 Gy. The observed reaction of irradiated and non-irradiated catalase with hydrogen peroxide is of the first order. Irradiation significantly decreases catalytic activity of catalase, but the activation energy does not depend markedly on the dose. The effect of irradiation is more significant at higher dose rate.

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