Showing papers on "Selective catalytic reduction published in 1975"

Catalytic reduction of aromatic nitro compounds with hydrazine in the presence of iron(iii) chloride and active carbon

Abstract: A catalytic reduction of aromatic nitro compounds to aromatic amino compounds with hydrazine in the presence of Fe(III) chloride and active carbon was studied. The corresponding amino compounds were obtained with excellent purities and in good yields. The method was also applied to the partial reduction of dinitro compounds.

Method and apparatus for determining ammonia concentration of gas

Abstract: An ammonia gas to be determined, and an oxidative gas containing nitrogen oxides in moles more than those of the ammonia are brought into contact with an analytical catalyst capable of forming nitrogen and water from ammonia and nitrogen oxides. Concentrations of nitrogen oxides of the gas before and after the contact with the analytical catalyst are determined, and an ammonia concentration of the gas is determined by converting the difference between the concentrations of nitrogen oxides to the ammonia concentration by calculation.

Selective hydrogenation of soybean oil: VII. Poisons and inhibitors for copper catalysts

Abstract: Hydrogenation rates for the catalytic reduction of soybean oil with a copper-on-silica catalyst increased when the oil was re-refined and bleached in the laboratory Purification of the re-refined and bleached oil by passage through alumina further enhanced hydrogenation rates Since these observations suggested that poisons were present in the oil, the effect of minor components of soybean oil upon the activity of copper catalysts was investigated Free fatty acids, monoglycerides, β-carotene, phosphoric acid, sodium soaps, phosphatides, glycerine, choline, ethanolamine, water, pheophytin, and pyrrole all reduced hydrogenation rates when added to the oil Organic sulfur added to the oil was a more effective catalyst inhibitor than inorganic sulfur added to the gas Catalyst activity was affected adversely when iron was added to the oil as a soap or when deposited on the catalyst during its preparation Squalene, copper soaps, and carbon monoxide had no influence on the activity of the catalyst Aging of soybean oil also had no effect There was no significant change in either selectivity or formation oftrans or conjugated diene isomer when these additives were added to the oil

Catalytic reduction of nitric oxide with ammonia over transition metal ion-exchanged y zeolites

Abstract: Catalytic reduction of nitric oxide with ammonia was studied over transition metal ion-exchanged Y zeolite (Me-Y) catalysts. Among various catalysts used, Cu(II)–Y was found to be of particular interest, exhibiting low temperature activity and an unusual catalytic activity-temperature profile with a maximum at 120°C. It was also observed that the catalytic activity was enhanced considerably when a second cation, especially Co (II) or Fe(III), was co-exchanged together with Cu(II) in Y zeolite. Such phenomena were discussed briefly.

A Study of Catalysis by Uranium Oxide and Its Mixed Catalysts. IX. A Catalytic Reduction of Nitric Oxide with Carbon Monoxide

Abstract: The reduction of NO with CO over the uranium oxide catalyst and its mixed catalysts with alkali metal oxide or alkaline earth metal oxide has been investigated using conventional flow and pulse reactors at temperatures of 250 to 450 °C under atmospheric pressure. The activity of the uranium oxide catalyst without any additive was higher than that of the Fe2O3 catalyst, although it was inferior to that of the CuO–Cr2O3 catalyst. The addition of alkali metal oxide or alkaline earth metal oxide to uranium oxide, particularly in the case of Cs2O or K2O, was effective in enhancing the catalyst activity. The W/F-conversion curves revealed that the reduction of NO to N2 proceeds consecutively, passing through N2O as a gas-phase intermediate. The reaction rates were formulated as r=kPCO1.0PNO0.4. The kinetic study suggested a redox reaction sequence. The oxidation states of the catalysts were discussed on the basis of X-ray diffractograms.

Catalytic reduction of halonitroaromatic compounds

Abstract: Halonitroaromatic compounds are reduced in the liquid phase with hydrogen, a palladium or platinum catalyst and a dehalogenation-suppressing amount of a compound of the formula ##STR1## wherein X is H, OH, alkyl, phenyl or mono- or dialkylphenyl.

Reproduction process of catalyst for removing nitrogen oxides in waste gas

Abstract: PURPOSE: Reproduction process of the catalyst used in the catalytic reduction of nitrogen oxides in waste gas with ammonia. COPYRIGHT: (C)1977,JPO&Japio

Treatment of water vapor generated in concentrating an aqueous urea solution

Abstract: Water vapor generated in concentrating an aqueous urea solution and containing a small amount of aqueous urea solution mist, ammonia and carbon dioxide is treated to recover urea and ammonia values. The water vapor is introduced into a separator wherein all of the urea solution mist is separated together with a part of the ammonia and the carbon dioxide to form a first condensate. The water vapor is then fed into a surface cooler wherein the water vapor is indirectly cooled to form a second condensate. The first condensate is used for process water and the second condensate is subjected to rectification to separate ammonia and carbon dioxide contained therein in the form of a mixed gas, which is recovered, from the remaining waste water free of ammonia and carbon dioxide.

Solid supported catalysts for catalytic reduction of nitrogen oxides in waste gases

Abstract: Solid supported catalysts for catalytic reduction of nitrogen oxide in waste gases utilizing ammonia as the reducing agent, the catalyst comprising at least one metallic oxide, sulfate or phosphate of a first transition metal supported on an alumina or silica-alumina carrier; the carrier containing from 0.03 to 20% by weight sulfur, based on the weight of the carrier, calculated as a sulfate or sulfite radical.

Eliminating nitrogen oxides from ammonia combustion gases - by catalytically splitting ammonia and reducing nitrogen oxides in effluents

Abstract: Nitrogen oxides are eliminated from gaseous effluents from internal combustion engines, or other devices using ammonia as a fuel, by passing the ammonia before the burning through a zone heated with effluent gases over an ammonia splitting catalyst and, after the burning, adding some ammonia to the effluent gases to reduce the nitrogen oxides over a catalyst. High degree of ammonia utilisation is achieved (>40%). The effluent gases are adequately purified. The burning temp. should not exceed 1500 degrees C as otherwise excessive formation of nitrogen oxides takes place.

The Catalytic Reduction of Nitric Oxide by Carbon Monoxide over a Fe2O3 Catalyst

Abstract: When nitric oxide was admitted during the course of the reduction of N2O by CO, a discontinuous increase in the N2O pressure and a decrease in the NO pressure were observed. The reduction of N2O stopped completely, and only the reduction of NO to N2O proceeded.

The Catalytic Reduction of Nitric Oxide over Supported Rhodium and Copper Nickel Catalysts

Abstract: Catalytic reduction of nitric oxide with CO and H2 reductants over Cu and/or Ni-Al2O3 catalysts and a Rh-Al2O3 catalyst was investigated. The comparative reactivity of CO and H2 over the base metal catalysts and noble metal catalyst showed the same trends.

Method for exhaust gas desulfurization

Abstract: PURPOSE:A method for exhaust gas desulfurization for exhaust gases from boilers by an ammonia - ammonium sulfate method.

Method of removing nox in exhaust gas

Abstract: PURPOSE: To remove NOx in exhaust gas by catalytic reduction with ammonia in the presence of honeycomb type catalyst while preventing degradation of the catalyst in relatively low temperature range COPYRIGHT: (C)1977,JPO&Japio

Catalytic reduction of aromatic nitro compounds with hydrazine in the presence of iron(iii) chloride and active carbon

Abstract: A catalytic reduction of aromatic nitro compounds to aromatic amino compounds with hydrazine in the presence of Fe(III) chloride and active carbon was studied. The corresponding amino compounds were obtained with excellent purities and in good yields. The method was also applied to the partial reduction of dinitro compounds.

Method for removing nitrogen oxides in waste gas

Abstract: PURPOSE: Method for removing NOx in waste gases by catalytic reduction with a ammonia, which can remove nitrofen oxides efficiently in a comparatively low temperature range and uses catalysts having excellent durability. COPYRIGHT: (C)1977,JPO&Japio

Catalyst and process for reducing nitrogen oxides

Abstract: A catalyst comprising an iron-chromium-oxygen type catalyst base and 0.1 through 20% of aluminum sulfate based on the weight of the above-mentioned catalyst base, is useful for reducing nitrogen oxides with ammonia at a temperature of 150° C or higher, to convert it to nitrogen and water.

Catalytic Reductions of NO with H2, CO or NH3 over Supported Metal Oxide Catalysts

Abstract: The roles of reducing agents such as H2, CO and NH3 in catalytic reduction of NO over supported metal oxide catalysts were studied from the viewpoint of reaction mechanisms. The reaction of NO with H2 or CO was proved to proceed through the redox cycles of the catalyst, that is, catalyst was oxidized by NO and then was reduced, to complete the catalytic sequence by the reducing agents. On the other hand, it was confirmed that NH3 or fragments of NH3 directly reacted with the adsorbed NO.These differences of the roles of reducing agents in the reaction mechanism satisfactorily explain some features of catalytic removal of NO in the practical process containing oxygen.

Nox reduction catalyst composition

Abstract: PURPOSE: A catalyst composition useful for catalytic reduction of NOx in the presence of NH 3 etc., NOx reducing property and resisting property to SOx of which have been improved by using a specific composition comprising Ti, etc. COPYRIGHT: (C)1977,JPO&Japio

A process for catalytic reduction of nitrogen oxides

Abstract: PURPOSE: A process for catalytically reducing nitrogen oxides in combustion equipment exhaust gas containing oxygen. COPYRIGHT: (C)1976,JPO&Japio

The catalytic reduction of nitric oxide by carbon monoxide over a fe2o3 catalyst

Abstract: When nitric oxide was admitted during the course of the reduction of N2O by CO, a discontinuous increase in the N2O pressure and a decrease in the NO pressure were observed. The reduction of N2O stopped completely, and only the reduction of NO to N2O proceeded.