Carbon monoxide hydrogenation catalyst

Frequency Response Chemisorption Studies of Carbon Monoxide Hydrogenation Catalysts... 

These two curves are similar for all types of carbon monoxide hydrogenation catalysts. They are important for explaining the different views concerning the optimum operation conditions for the synthesis. If the price of the synthesis gas determines the suitability of the process, working at comparatively low space velocities will be inevitable. If, however, the capital costs of reactor and catalyst are the more important items, it will be more favorable to work at high space velocities, if the problem of the removal of the exothermic reaction heat can be solved,... 

Carbon monoxide hydrogenation catalysts have been obtained by thermal decomposition of intrazeolite iron bis(toluene) complexes [258],... 

The direct, one-step production of DMF from carbon monoxide, hydrogen, and ammonia has also been reported. A mthenium carbonyl catalyst is used, either ia a polar organic solvent (20) or ia a phosphonium molten salt medium (21). 

Garbonylation of Olefins. The carbonylation of olefins is a process of immense industrial importance. The process includes hydroformylation and hydrosdylation of an olefin. The hydroformylation reaction, or oxo process (qv), leads to the formation of aldehydes (qv) from olefins, carbon monoxide, hydrogen, and a transition-metal carbonyl. The hydro sdylation reaction involves addition of a sdane to an olefin (126,127). One of the most important processes in the carbonylation of olefins uses Co2(CO)g or its derivatives with phosphoms ligands as a catalyst. Propionaldehyde (128) and butyraldehyde (qv) (129) are synthesized industrially according to the following equation ... 

As a chemical compound, methane is not very reactive. It does not react with acids or bases under normal conditions. It reacts, however, with a limited number of reagents such as oxygen and chlorine under specific conditions. For example, it is partially oxidized with a limited amount of oxygen to a carbon monoxide-hydrogen mixture at high temperatures in presence of a catalyst. The mixture (synthesis gas) is an important building block for many chemicals. (Chapter 5). 

Catalysts in an oxidized state showed high activity in the oxidation of carbon monoxide [nickel catalysts (146) ] and hydrogen [molybdenum catalysts (146a)]. 

Most low-valence metal complexes are generally deactivated by air and sometimes also by water. Carbon monoxide, hydrogen cyanide, and PH3 frequently act as poisons for these catalysts. Poisoning by strongly co-ordinating molecules occurs by formation of catalytically inert complexes. An example is the poisoning of Wilkinson s catalyst for alkene hydrogenation ... 

Carbon monoxide, hydrogen cyanide, and nitriles also react with aromatic compounds in the presence of strong acids or Friedel-Crafts catalysts to introduce formyl or acyl substituents. The active electrophiles are believed to be dications resulting from diprotonation of CO, HCN, or the nitrile.64 The general outlines of the mechanisms of these reactions are given below. 

Lee, D.-K., Lee, J.-H., and Ihm, S.-K. 1988. Effect of carbon deposits on carbon monoxide hydrogenation over alumina-supported cobalt catalysts. Appl. Catal. 36 199-207. 

Lahtinen, J., Anraku, T., and Somotjai, G. A. 1993. Carbon monoxide hydrogenation on cobalt foil and on thin cobalt film model catalysts. J. Catal. 142 206-25. 

Machocki, A. 1991. Formation of carbonaceous deposit and its effect on carbon monoxide hydrogenation on iron-based catalysts. Appl. Catal. 70 237-52. 

Campbell, C. T., and Goodman, D. W. 1982. A surface science investigation of the role of potassium promoters in nickel catalysts for carbon monoxide hydrogenation. Surf. Sci. 123 413-26. 

Lanthanum rhodate catalysts, carbon monoxide hydrogenation, 36 296-297 Fischer-Tropsch reaction, temperature effect, 36 297-298... 

Photolysis of an aqueous solution containing chloroform (314 pmol) and the catalyst [Pt(cohoid)/Ru(bpy) /MV/EDTA] yielded the following products after 15 h (mol detected) chloride ions (852), methane (265), ethylene (0.05), ethane (0.52), and unreacted chloroform (10.5) (Tan and Wang, 1987). In the troposphere, photolysis of chloroform via OH radicals may yield formyl chloride, carbon monoxide, hydrogen chloride, and phosgene as the principal products (Spence et al., 1976). Phosgene is hydrolyzed readily to hydrogen chloride and carbon dioxide (Morrison and Boyd, 1971). 

Aryl halides may be carbonylated using several different palladium complexes and several different hydrogen donors839,840,842,843. In most synthetically useful reactions the conditions are reasonably low pressure (up to 6 bar) and reasonably low temperatures (below 100 °C). Halobenzenes have also been successfully carbonylated at 30 bar using a carbon monoxide/hydrogen mixture in the presence of a palladium catalyst and triethy-lamine. In this case the halobenzene must first be complexed with chromium tricarbonyl844. 

A small modification of the above design, in which the catalyst in the form of granules or pellets is placed in an annular basket made of wire mesh fitted close to the reactor wall, has also been examined. The use of such an annular basket-type reactor has been reported by Tajbl et al. (1967), Relyea and Perlmutter (1968), and Lakshmanan and Rouleau (1970). The basic features of this reactor are the same as the ones described above. The reactor has been used to carry out high-pressure, high-temperature catalytic methanation of mixtures of carbon monoxide/hydrogen and carbon dioxide/hydrogen. 

Promoters are often needed in addition to the actual catalyst itself. In general promoters increase the rate of a desired reaction this can occur because of a general increase in reaction rates or because of an increase in selectivity towards one product by comparison to others. Most promoters tend to be specific to a particular reaction and catalyst but some promoters can accelerate different reactions. For example potassium (usually added as K2O) promotes the silver catalyzed ethylene oxidation to ethylene oxide (Section 2.4), and also promotes carbon monoxide hydrogenation over Fe catalysts (Section 4.8). 

Bhore, N. A. Modifiers in Rhodium Catalysts for Carbon Monoxide Hydrogenation Structure - Activity Relationships. RlD. Thesis, University of Delaware, 1989. Hall, W. K.., Proceedings of the Climax Fourth International Conference on the Chemistry and Uses of Molybdenum, Barry and Mitchell, Eds., Climax Molybdenum Co., Ann Aibor, MI, p. 224 - 233 (1982). 

A mixture of carbon monoxide, hydrogen, and carbon dioxide is produced by steam reforming, a process in which natural gas and steam are mixed and reacted in a reformer operated at 1.6 MPa. Natural gas may be assumed to consist entirely of methane (CH4), although other compounds may be present in small concentrations. In the present process, steam and natural gas are fed to the reformer in a ratio of 3.0 moles of steam per mole of methane. The reformer consists of an arrangement of vertical tubes filled with nickel-impregnated ceramic catalyst. Rows of these tubes are located inside an insulated firebox, where they are heated by the combustion of natural gas. 

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