Carbon monoxide oxidation— temperature effect

Oxidation. Carbon monoxide can be oxidized without a catalyst or at a controlled rate with a catalyst (eq. 4) (26). Carbon monoxide oxidation proceeds explosively if the gases are mixed stoichiometticaHy and then ignited. Surface burning will continue at temperatures above 1173 K, but the reaction is slow below 923 K without a catalyst. HopcaUte, a mixture of manganese and copper oxides, catalyzes carbon monoxide oxidation at room temperature it was used in gas masks during World War I to destroy low levels of carbon monoxide. Catalysts prepared from platinum and palladium are particularly effective for carbon monoxide oxidation at 323 K and at space velocities of 50 to 10, 000 h . Such catalysts are used in catalytic converters on automobiles (27) (see Exhaust CONTHOL, automotive). 

Whittle DM, et al. Co-precipitated copper zinc oxide catalysts for ambient temperature carbon monoxide oxidation effect of precipitate ageing on catalyst activity. Phys Chem Chem Phys. 2002 4(23) 5915-20. 

Ferric oxide is reduced to ferrous oxide or the metal, according to circumstances, by carbon monoxide. At temperatures below 1000° C. the dry gas is more effective than the moist, but at 1050° C. both moist and dry gases behave alike.2 At and below 850° C. the iron is converted into carbide.3 At 700° C. the reaction... 

Engel, T. Ertl, G. Advances in Catalysis, Academic Press, New York, (1979). Cant, N. W. Metal crystalhte size effects and low-temperature deactivation in carbon monoxide oxidation over platinum. Journal of Catalysis 62, 173-175 (1980). 

A. A. Mirzaei, H. R. Shaterian, R. W. Joyner, M. Stockenhuber, S. H. Taylor, and G. J. Hutchings, Ambient temperature carbon monoxide oxidation using copper manganese oxide catalysts effect of residual Na+ acting as catalyst poison, Catalysis Communications, vol. 4, no. 1, pp. 17-20, 2003. 

A sophisticated quantitative analysis of experimental data was performed by Voltz et al. (96). Their experiment was performed over commercially available platinum catalysts on pellets and monoliths, with temperatures and gaseous compositions simulating exhaust gases. They found that carbon monoxide, propylene, and nitric oxide all exhibit strong poisoning effects on all kinetic rates. Their data can be fitted by equations of the form ... 

The first scheme was ruled out by showing that, at room temperature, a surface formed by very brief exposure of the oxygen-saturated surface to carbon monoxide is stable after removal of the carbon monoxide from the reaction chamber. In other words, no further surface carbide formed by lateral reactions of adsorbed carbon monoxide with surface oxygen atoms. The second scheme was ruled out by showing that exposure of the surface formed in the latter experiment to oxygen had no effect. Consequently the third scheme is believed to represent the mechanism of oxidation of carbon monoxide at the step and kink sites of platinum. 

The vendor claims that CORPEX chemicals are more effective than other existing chelants in removing heavy metals and radioactive metal ions because of their unique molecular structures and enhanced solubility in water. They are effective over a wide range of temperatures (from freezing to boiling) and variable pH (from 1 to 14). The chemicals can be oxidized after the cleaning process and no undesirable residues are left—only water, carbon dioxide, carbon monoxide, and nitrogen. 

The CBC technology operates at relatively low temperatures [approximately 1600°F (870°C)], thus reducing operation costs. The high turbulence produces a uniform temperature and promotes the complete mixing of the waste material during combustion. The effective mixing and relatively low temperature also reduce emissions of carbon monoxide and nitrogen oxides. 

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