Carbon monoxide, viii

In the various laboratory studies when the outlet gas composition was not at equilibrium, it was observed that the steam-to-gas ratio (S/G) significantly affected the hydrogen leakage while the carbon monoxide still remained low. On the assumption that various reactions will proceed at different rates, a study was made to determine the effect of S/G on the reaction rate. The conditions for this test are presented in Table VII the findings are tabulated in Table VIII. 

POLYCARBOXYLIC ACIDS The gamma radiolysis of the homopolymers of acrylic, methacrylic and itaconic acids have been investigated in the solid state at 303 K, and in each case the yields of carbon monoxide, carbon dioxide and of radical intermediates have been measured. These are reported in Tables VII and VIII respectively. 

VIII. MAGNESIUM COMPLEXES WITH CARBON MONOXIDE... 

Most Group VIII metals adsorb carbon monoxide dissociatively, and, consequently, they are good Fischer-Tropsch catalysts.240 In contrast, Pd, Pt, Ir, and Cu do not dissociate carbon monoxide. Of these metals, copper and more recently palladium were found to be excellent methanol-forming catalysts. 

Throughout these studies, no product other than propane was observed. However, subsequent studies by Sinfelt et al. [249—251] using silica-supported Group VIII metals (Co, Ni, Cu, Ru, Os, Rh, Ir, Pd and Pt) have shown that, in addition to hydrogenation, hydrocracking to ethane and methane occurs with cobalt, nickel, ruthenium and osmium, but not with the other metals studied. From the metal surface areas determined by hydrogen and carbon monoxide chemisorption, the specific activities of... 

As illustrated in Scheme 47, various group-VIII metals catalyze the hy-droformylation of olefins by using hydrogen and carbon monoxide to form aldehyde products. Although industrial oxo processes use Co catalysts, the asymmetric reactions use mainly Rh(I)- or Pt(II)-based catalysts. 

The hydrocarboxylation reaction of alkenes and alkynes is one which utilizes carbon monoxide to produce carboxylic acid derivatives. The source of hydrogen is a protic solvent (equation 35) dihydrogen is not usually added to the reaction. There are a number of variations to this reaction, since the solvent can be water, alcohols, amines, acids, etc. The catalysts can be Group VIII-X transition metals, but cobalt, rhodium, nickel, palladium and platinum have found the most use. 

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... 

We further investigated the formation of Ni(CO)4 and cobalt carbonyls by the action of carbon monoxide on a suspension of the appropriate metal hydroxide [Blanchard and Gilmont (82)] by using potassium cyanide (83) (see Section VIII). 

A 3 x 3 x 3 unit cell was used to represent the interactions of CH O with a flat Cu(lll) surface (Fig. 14). The binding energies and site preferences of methoxy species (CH3O), adsorbed formaldehyde (CH20), formyl species (CHO), carbon monoxide, and hydrogen atoms were determined for the Cu(lll) surfaces. The calculations were performed with one-ninth ML coverage of the adsorbate. Table VIII is a summary of the changes in electronic... 

Carbon monoxide has been found to be surprisingly reactive toward the metals in Group VIII, in both their oxidized and unoxidized states. A sizable number of compounds exist in which one or more CO molecules are attached to a metal atom through the carbon typical of these are nickel tetracarbonyl, Ni(CO)4, iron pentacarbonyl, Fe(CO) cobalt carbonyl hydride, Co(CO)4H platinum carbonyl chloride, Pt(CO)2Cl2 and more complicated molecules such as Co4(CO)i2. 

Hexafluorobutyne reacts with [WBr2(CO)4]2 to form an unusual five-coordinate complex, W(CF3C=CCF3)2(CO)Br2, with vco at 2172 cm-1, above the frequency of free carbon monoxide (2143 cm-1) or that of H3BCO (2165 cm-1) (86). Further data characterizing this material will be informative it is known to react with P(OMe)3, but it does not form an r>2-vinyl product (see Section VIII,A). 

All the binary Cu/ZnO catalysts were found highly selective toward methanol without DME, methane, or higher alcohols and hydrocarbons detected in the product by sensitive gas chromatographic methods (59). Several of the composites were also found to be very active when subjected to a standard test with synthesis gas C0/C02/H2 = 24/6/70 at gas hourly space velocity of 5000 hr- pressure 75 atm, and temperature 250°C. The activities, expressed as carbon conversions and yields, are summarized in Table VIII. The end members of the series, pure copper and pure zinc oxide, were inactive under these testing conditions, and maximum activity was obtained for the composition Cu/ZnO = 30/70. The yields per unit weight, per unit area of the catalyst or the individual components, turnover rates per site titratable by irreversible oxygen and by irreversible carbon monoxide, are graphically... 

Dodeeacarbonyltriosmium was first obtained from the reaction of osmium (VIII) tetraoxide with carbon monoxide in the gas phase.6 Yields by this method are low. More recently, Bradford and Nyholm10 have obtained this carbonyl in high yields from the reaction of osmium tetraoxide with carbon monoxide in xylene under conditions of moderate pressure (128 atmospheres) and temperature (175°). The method... 

Carbon monoxide has been shown (8) to reversibly add across the MeM bond of Mo2(0But)6 to give Mo2(OBut)64i -CO) (M=M). See VIII before. We have previously speculated (46) that this carbene-like addition to a MeM bond could be one of general class of reactions that are common to dinuclear compounds. Similar additions of CO across Pd-Pd and Pt-Pt bonds have been reported (47). 

Insertions of Carbon Monoxide in Complexes of Group VIII Metals. 

Carbon monoxide insertion reactions in hydrocarbyl complexes of group VIII are particularly relevant because several industrial processes involving carbonylation of an organic substrate are catalyzed by metals belonging to this group. In the subsections that follow, reference to catalytic processes is made on each specific occasion. 

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