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Pd/C Catalyst (c + catalyst)
Selected AbstractsCombinatorial Search for Quaternary Methanol Tolerant Oxygen Electro-Reduction CatalystFUEL CELLS, Issue 1 2010M. K. Jeon Abstract A combinatorial library containing 645 different compositions was synthesised and characterised for methanol tolerant oxygen electro-reduction reaction (ORR) catalytic performance. The library was composed of compositions involving between 1 and 4 metals among Pt, Ru, Fe, Mo and Se. In an optical screening test, Pt(50)Ru(10)Fe(20)Se(10) composition exhibited the highest ORR activity in the presence of methanol. This composition was further investigated by synthesis and characterisation of a powder version catalyst [Pt(50)Ru(10)Fe(20)Se(10)/C]. At 0.85,V [vs. reversible hydrogen electrode (RHE)] in the absence of methanol, the Pt/C catalyst exhibited higher ORR current (0.0990,mA) than the Pt(50)Ru(10)Fe(20)Se(10)/C catalyst (0.0902,mA). But much higher specific activity (12.7 ,A cmpt,2) was observed in the Pt(50)Ru(10)Fe(20)Se(10)/C catalyst than for the Pt/C catalyst 6.51 ,A cmpt,2). In the presence of methanol, the ORR current decreased by 0.0343 and 0.247,mA for the Pt(50)Ru(10)Fe(20)Se(10)/C and Pt/C catalysts, respectively, which proved the excellent methanol tolerance of the Pt(50)Ru(10)Fe(20)Se(10)/C catalyst. [source] Ring Opening of 1-Azabicyclo[1.1.0]butanes with Hydrazoic Acid , a Facile Access to N -Unsubstituted Azetidin-3-AminesHELVETICA CHIMICA ACTA, Issue 7 2005Grzegorz Mlosto Sterically congested 1-azabicyclo[1.1.0]butanes 1 add hydrazoic acid smoothly at 0,5°, giving 3-azidoazetidines 2 in good to excellent yields. After hydrogenolysis over Pd/C catalyst, compounds 2 were converted into N -unsubstituted azetidin-3-amines 4. Attempted reduction of 2a with Raney -Ni led to a mixture of the expected azetidin-3-amine 4a and the ring-enlarged 2,5-dihydro-1H -imidazole derivative 5. [source] Synthesis of tritium labelled CHS 828 and its prodrug EB 1627JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 11 2005Søren Christian Schou Abstract The potent antitumoral cyanoguanidine CHS 828 and its prodrug EB 1627 have successfully been labelled with tritium. The pyridyl-3,5-dibromo derivative of CHS 828 was debrominated with tritium-gas using Pd/C catalyst to give [pyridyl -3,5- 3H2]-CHS 828 with a radiochemical purity of 99.3% and a specific activity of 1960 GBq/mmol. Similarly, the pyridyl-3-bromo derivative of the prodrug EB 1627 was debrominated with tritium-gas to give [pyridyl -3- 3H]-EB 1627 with a radiochemical purity of 98.1% and a specific activity of 894 GBq/mmol. Copyright © 2005 John Wiley & Sons, Ltd. [source] Integration of methanation into the hydrogenation process of benzoic acidAICHE JOURNAL, Issue 1 2009Baoning Zong Abstract The traditional industrial process for hydrogenation of benzoic acid to cyclohexanecarboxylic acid (CCA) has drawbacks of low-activity and fast deactivation of the Pd/C catalyst due to the poisoning of CO arising from the decarboxylation of CCA. A novel rapidly quenched skeletal NiCrFe promoter (RQ NiCrFe) is developed for the methanation of CO to harmless CH4. Evaluations in bench-scale autoclave and in traditional industrial equipment verified that RQ NiCrFe was very effective in promoting the activity of the Pd/C catalyst in the hydrogenation of benzoic acid. In order to solve the catalyst recycle and separation problem introduced by RQ NiCrFe, the industrial process was modified by incorporating a hydraulic cyclone and a magnetic separator to the separation unit. The modified process showed merits of lower costs of catalyst and operation, higher productivity, and better product purity than the traditional process. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source] Effect of Halide and Acid Additives on the Direct Synthesis of Hydrogen Peroxide using Supported Gold,Palladium CatalystsCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 6 2009Edwin Ntainjua N. Dr. Abstract Acidity is crucial: The effect of halide and acid addition on the direct synthesis of hydrogen peroxide is studied for magnesium oxide- and carbon-supported bimetallic gold,palladium catalysts. When using a Au,Pd/C catalyst, the acidity of the methanol/water solvent has a profound effect on the productivity (P). The effect of halide and acid addition on the direct synthesis of hydrogen peroxide is studied for magnesium oxide- and carbon-supported bimetallic gold,palladium catalysts. The addition of acids decreases the hydrogenation/decomposition of hydrogen peroxide, and the effect is particularly pronounced for the magnesium oxide-supported catalysts whilst for carbon-supported catalysts the pH requires close control to optimize hydrogen peroxide synthesis. The addition of bromide leads to a marked decrease in the hydrogenation/decomposition of hydrogen peroxide with either catalyst. These effects are discussed in terms of the structure of the gold,palladium alloy nanoparticles and the isoelectric point of the support. We conclude that with the highly active carbon-supported gold,palladium catalysts these additives are not required and that therefore this system presents the potential for the direct synthesis of hydrogen peroxide to be operated using green process technology. [source] Preparation of 2-Quinolones by Sequential Heck Reduction,Cyclization (HRC) Reactions by Using a Multitask Palladium CatalystCHEMISTRY - A EUROPEAN JOURNAL, Issue 29 2009François-Xavier Felpin Dr. Abstract One-pot sequential Heck reduction,cyclization (HRC) reactions leading to the synthesis of substituted 2-quinolones have been developed by using a heterogeneous or mixed homogeneous/heterogeneous multitask palladium catalyst with charcoal as a support. The whole sequence occurs under very mild conditions without the need for additives (ligand or base) by taking advantage of the high reactivity of aryldiazonium salts as "super electrophiles". Recycling experiments showed that the reused heterogeneous Pd0/C catalyst was not able to promote another HRC sequence but was, however, still highly active for hydrogenation, hydrodehalogenation, as well as hydrogenolysis reactions. [source] High Performance Carbon-Supported Core@Shell PdSn@Pt Electrocatalysts for Oxygen Reduction ReactionFUEL CELLS, Issue 4 2010W. Zhang Abstract In this report, a low-cost and high performance PdSn@Pt/C catalyst with core,shell structure is prepared by two-stage route. X-ray diffraction (XRD) and transmission electron microscopy (TEM) examinations show that the composite catalyst particles distribution is quite homogeneous and has a high surface area and the PdSn@Pt/C catalyst has an average diameter of ca. 5.6,nm. The oxygen reduction reaction (ORR) activity of PdSn@Pt/C was higher than commercial Pt/C catalyst. Catalytic activity is studied by cyclic voltammetry. High electrocatalytic activities could be attributed to the synergistic effect between Pt and PdSn. [source] Novel ZnX2 -Modulated Pd/C and Pt/C Catalysts for Chemoselective Hydrogenation and Hydrogenolysis of Halogen-Substituted Nitroarenes, Alkenes, Benzyl Ethers, and Aromatic Ketones.CHEMINFORM, Issue 49 2003George Wu Abstract For Abstract see ChemInform Abstract in Full Text. [source] High Performance Carbon-Supported Core@Shell PdSn@Pt Electrocatalysts for Oxygen Reduction ReactionFUEL CELLS, Issue 4 2010W. Zhang Abstract In this report, a low-cost and high performance PdSn@Pt/C catalyst with core,shell structure is prepared by two-stage route. X-ray diffraction (XRD) and transmission electron microscopy (TEM) examinations show that the composite catalyst particles distribution is quite homogeneous and has a high surface area and the PdSn@Pt/C catalyst has an average diameter of ca. 5.6,nm. The oxygen reduction reaction (ORR) activity of PdSn@Pt/C was higher than commercial Pt/C catalyst. Catalytic activity is studied by cyclic voltammetry. High electrocatalytic activities could be attributed to the synergistic effect between Pt and PdSn. [source] Combinatorial Search for Quaternary Methanol Tolerant Oxygen Electro-Reduction CatalystFUEL CELLS, Issue 1 2010M. K. Jeon Abstract A combinatorial library containing 645 different compositions was synthesised and characterised for methanol tolerant oxygen electro-reduction reaction (ORR) catalytic performance. The library was composed of compositions involving between 1 and 4 metals among Pt, Ru, Fe, Mo and Se. In an optical screening test, Pt(50)Ru(10)Fe(20)Se(10) composition exhibited the highest ORR activity in the presence of methanol. This composition was further investigated by synthesis and characterisation of a powder version catalyst [Pt(50)Ru(10)Fe(20)Se(10)/C]. At 0.85,V [vs. reversible hydrogen electrode (RHE)] in the absence of methanol, the Pt/C catalyst exhibited higher ORR current (0.0990,mA) than the Pt(50)Ru(10)Fe(20)Se(10)/C catalyst (0.0902,mA). But much higher specific activity (12.7 ,A cmpt,2) was observed in the Pt(50)Ru(10)Fe(20)Se(10)/C catalyst than for the Pt/C catalyst 6.51 ,A cmpt,2). In the presence of methanol, the ORR current decreased by 0.0343 and 0.247,mA for the Pt(50)Ru(10)Fe(20)Se(10)/C and Pt/C catalysts, respectively, which proved the excellent methanol tolerance of the Pt(50)Ru(10)Fe(20)Se(10)/C catalyst. [source] Selective Oxidation of Alcohols to Carbonyl Compounds and Carboxylic Acids with Platinum Group Metal CatalystsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2003Ross Anderson Abstract The use of platinum group metal (PGM) catalysts for the selective oxidation of various primary and secondary alcohols under mild conditions is described. High throughput screening (HTS) techniques have been used to identify trends in catalyst activity and product selectivity. Using air as oxidant and water as solvent 5% Pt, 1% Bi/C has been identified as an efficient catalyst for the transformation of 2-octanol to 2-octanone and 1-octanol to octanoic acid. To improve aldehyde selectivity the promotion of Pt/Al2O3 and Ru/C catalysts has been investigated. The use of H2O2 as oxidant has been demonstrated as a suitable alternative to air. [source] | |||||||||||||||||||