摘要:
The present invention concerns a method of preparation of nanoparticular metal oxide catalysts having a narrow particle size distribution. In particular, the invention concerns preparation of nanoparticular metal oxide catalyst precursors comprising combustible crystallization seeds upon which the catalyst metai oxide is co-precipitated with the carrier metal oxide, which crystallization seeds are removed by combustion in a final calcining step. The present invention also concerns processes wherein the nanoparticular metal oxide catalysts of the invention are used, such as SCR (deNOx) reactions of nitrogen oxides with ammonia or urea as reductant, oxidations of alcohols or aldehydes with dioxygen or air to provide aldehydes, ketones or carboxylic acids, and photocatalytic oxidation of volatile organic compounds (VOCs).
摘要:
The present invention concerns a process for selectively removing nitrogen oxides (NOx) from exhaust or flue gasses, especially from gases arising from the burning of biomass, combined biomass-fossil fuel and from waste incineration units, and a catalyst for this process. The process relates to the selective catalytic reduction (SCR) of NOx with ammonia as reductant which is the most common method to catalytically reduce NOx in flue gasses from stationary sources. SCR systems are designed to clean the nitrogen dioxide (NO 2 and nitrogen oxide (NO) out of flue gasses. The present invention relates to a process for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of a) a formed porous superacidic support b) a metal oxide catalytic component deposited on said support selected from the group consisting of Cu, V, Fe, Cr, Mn, Mo and mixtures thereof. The support can e.g. be obtained by the adsorbing of sulfate ions onto amorphous or crystalline inorganic oxide of Zr, Ti, Fe, Sn, Si, Al, and Hf, followed by calcination in air.
摘要:
Cu/mordenite catalysts were found to be highly active for the SCR of NO with NH 3 and exhibited high resistance to alkali poisoning. Redox and acidic properties of Cu/mordenite were well preserved after poisoning with potassium unlike that of vanadium catalysts. Fe-mordenite catalysts also revealed much higher alkali resistivity than that of commercial V 2 O 5 /WO 3 -TiO 2 (VWT) SCR catalyst which is currently used for NO x abatement in stationary installations. Unique support properties like high surface area and surface acidity, which are not available in the commercial VWT catalyst, seem to be essential requirements for the high alkali resistance. Mordenite-type zeolite based catalysts could therefore be attractive alternatives to conventional SCR catalysts for biomass fired power plant flue gas treatment.
摘要:
The present invention concerns a catalyst system in particular a catalyst system comprising Palladium (Pd), a zwitterion and/or an acid-functionalized ionic liquid, and one or more phosphine ligands, wherein the Pd catalyst can be provided by a complex precursor, such as Pd(CH3COO)2, PdCI2, Pd(CH3COCHCOCH3), Pd (CF3COO)2, Pd(PPh3)4 or Pd2(dibenzylideneacetone)3. Such catalyst systems can be used for e.g. alkoxycarbonylation reactions, carboxylation reactions, and/or in a co-polymerization reaction, e.g. in the production of methyl propionate and/or propanoic acid, optionally in processes forming methyl methacrylate and/or methacrylic acid. Catalyst systems according to the invention are suitable for reactions forming separable product and catalyst phases and supported ionic liquid phase SILP applications.