Interaction of Carbon Monoxide

The evaluation of the observed features in the electfonic stfucture within this chapter is performed manually, without the help of the automated treatment tool (Sect. 2.2.3) as the spectral features were simply too weak to do so. This is due to the fact that the channeltron of the HAC was replaced before the measurements reported in this section and consequently EE spectra were not obtained with an optimized setup at full sensitivity. 

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The most important route for the production of formaldehyde is from methanol, this normally being prepared by interaction of carbon monoxide and hydrogen. 

The product of interaction of carbon monoxide with sodium (not sodium carbonyl as previously thought [2], but the hexamer), sodium benzenehexoxide, is shock sensitive, explodes at 90°C and contact with water causes explosion or ignition to occur [4], Later work [5] makes it likely that this compound is, in fact, the dimer disodium ethynediolate. 

Thermochemical Cycles Testing the Formation of Gaseous (Cycle 1) or Adsorbed (Cycle 2) Carbon Dioxide by the Interaction of Carbon Monoxide with Oxygen Preadsorbed on Gallium-Doped Nickel Oxide ... 

Fig. 26. Differential heats of interaction of carbon monoxide at 30°C with a sample of gallium-doped nickel oxide, containing a limited amount (0.4 cm3 02 gm l) of preadsorbed oxygen.

Fig. 29. Differential heats of interaction of carbon monoxide, at 200°C, with samples of nickel oxide containing excess oxygen, preadsorbed rapidly (A) or slowly (B).

Bagley, K. A., Van Garderen, C. J., Chen, M., Duin, E. C., Albracht, S. P. and Woodruff, W. H. (1994) Infrared studies on the interaction of carbon monoxide with divalent nickel in hydrogenase from Chromatium vinosum. Biochemistry, 33, 9229-36. 

Van der Zwaan JW, Albracht SPJ, Fontijn RD, Roelofs YBM. 1986. EPR evidence for direct interaction of carbon monoxide with nickel in hydrogenase from Chromatium vinosum. Biochim Biophys Acta 872 208-15. 

Finally, LEED, TDS and UPS studies on the interaction of carbon monoxide with the hexagonally closest packed faces of the group VIII metals show numerous similarities. This is not... 

Gautier3 has studied the interaction of carbon monoxide and hydrogen at 300° to 1250° C. A mixture of 3 volumes of hydrogen and 1 volume of the monoxide passed through a porcelain tube begins to react at 400° C., water, carbon dioxide, and a small proportion of methane being formed. The action attains its maximum at 1000° C. 

In both homogeneous and heterogeneous catalysis, carbon monoxide activation involves first the coordinaiive interaction of carbon monoxide with a metal acceptor center. Carbon monoxide, being a weak donor base, does not react with a proton and produces only a vety weak interaction with a hard acid center such as BH3, With less hard Lewis centers, such as CuX, AgX, AuXj etc. (X - halogen), more or less stable carbon monoxide adducts can be isolated. A variety of modes of CO coordination in well characterized organometallic complexes is known. Scheme 1 contains some selected examples. 

The interaction of carbon monoxide with palladium salts produces under rela tively mild (but rigorously anhydrous) conditions such species as [Pd(CO)Cl2 ] 2, [Pdj CU(CO)j and probably, under higlier carbon monoxide pressure, species such as Pd(CO)2 CI3. Only under severe conditions are reduced species such as [Pd(CO)Xlrt X = Br. Cl formed, but since the catalytic reaction is carried out under a relatively mild carbon monoxide pressure, it is rather improbable that such reduced species are present in considerable amounts. For a general discus sion of the mechanism, however, the characteri .ation of the exact nature of the palladium(Il) carbonyl complexes formed m sint is irrelevant, ( nerally speaking, carbon monoxide coordination to a Pd(U) ion will produce a facile nucleophilic attack on CO by the alcohol. The question of whether such an attack is produced by free alcohol or by a palladium bonded alkoxy group, is worth examination. 

During the last five years a number of researches in other laboratories have added substantially to our knowledge of the interaction of carbon monoxide and carbon dioxide with oxygen at oxide surfaces, especially nickel oxide. There is support for the idea presented in the foregoing sections that these gases can produce on the surface of the oxide a species with formula CO3, but opinions differ as to its precise description and in particular the extent to which lattice oxide ions, as opposed to adsorbed oxygen ions, are involved. The more important of these researches are summarized and critically examined in this Section. 

A. Interaction of Carbon Monoxide with Preadsorbed Oxygen... 197... 

From these experiments, it was concluded that a fraction of the oxygen ions adsorbed at 250° presents, at room temperatme, the same reactivity toward carbon monoxide as oxygen species chemisorbed at room temperature, since in both cases carbon dioxide is formed. From the differential heats of interaction of carbon monoxide at room temperature (hrst adsorption) with this fraction of the oxygen species adsorbed at 250°, it has been possible to show that the heat of adsorption of these adsorbed ions (62 kcal/mole) is very similar to initial heat of adsorption of oxygen at 30° (60 kcal/mole) (Fig. 4). Since the formation of O2 ions is not probable at 250° on a divided reactive oxide, we assume that at both temperatures (30 and 250°) oxygen is adsorbed as O ions. 

The calorimetric study of interactions on the surface of gallium-doped nickel oxide therefore yields results which are similar to those obtained on pure Ni0(250°), although the incorporation of trivalent ions changes somewhat the surface affinity toward oxygen. In both cases, two reaction mechanisms for the production of gaseous carbon dioxide are probable. In mechanism II, a reaction intermediate, C03-(ads) is formed whereas, in mechanism I, gaseous carbon dioxide is produced directly by the interaction of carbon monoxide with adsorbed... 

On the other hand, the mechanism of the interaction of carbon monoxide with preadsorbed oxygen appears to be closely related to the strength of the bond between the oxygen ion and the surface site. When... 

Fia. 33. Differential heats of interaction of carbon monoxide with NiO(200°) at 200°. 

Fio. 36. Differential heata of interaction of carbon monoxide at 200° with NiO(200°) containing preadsorbed oxygen. 

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