Hydrogenation cobalt catalysis

The addition of increasing amounts of iodine promoters accelerates the hydrocarbonylation of methanol, but at the same time detioriates the hydrogenation ability of the cobalt catalysis. To obtain a high ethanol selectivity under these conditions, catalysts active for hydrogenation in the presence of iodine have to be added. Ruthenium compounds have been proved to be most suitable, as was mentioned earlier. Althou no detailed studies on the ruthenium intermediates involved are available, it is well known that aliphatic aldehydes... 

Oxo reaction. A U.S. patent filed in 1938 by the German Otto Roelen and issued in 1943 disclosed the addition to an olefin of carbon monoxide and hydrogen under catalysis by cobalt, thorium oxide, or kieselguhr. The reaction was at first described as an oxo synthesis, but after Adkins and Krsek had examined the... 

According to the various reaction conditions, especially those of temperature and pressure, aldehydes or alcohols were produced with cobalt catalysis by reaction of olefins with carbon monoxide and hydrogen, as shown by Equation 1 of Table 1. Acetic acid is formed by a specific reaction according to Equation 2. 

Takahashi [31]. To get good yields, nitrobenzene was added as a hydrogen acceptor (Scheme 1.11a). But on running the carbonylation of azobenzene via cobalt catalysis, quinazoUne was obtained as the terminal product Furthermore, Chatani and coworkers described a rhodium-catalyzed synthesis of maleimides starting from a combination of alkynes and pyridine-2-yhnethylamine in the presence of CO (Scheme 1.11b) [53]. 

The properties of polyurethanes derived from the hydroformylation of fatty acid derivatives, subsequent hydrogenation, and reaction with isocyanates such as toluene diisocyanate (TDl), methylene diphenyl-4,4-diisocyanate (MDI), and 1,6-hexamethylenediisocyanate (HDI) may be strongly dependent on the metal used for the hydroformylation [12a, 62]. At high conversion rates with a rhodium catalyst, a rigid polyurethane A is formed, whereas under the conditions of cobalt catalysis and low conversion a hard rubber or rigid plastic (polyurethane B) with lower mechanical strength results (Scheme 6.100). 

During World War II German scientists developed a method of hydrogenating soHd fuels to remove the sulfur by using a cobalt catalyst (see Coal CONVERSION processes). Subsequently, various American oil refining companies used the process in the hydrocracking of cmde fuels (see CATALYSIS SuLFUR REMOVAL AND RECOVERY). Cobalt catalysts are also used in the Fisher-Tropsch method of synthesizing Hquid fuels (21—23) (see Fuels, synthetic). 

Cobalt(II) oxalate [814-89-1], C0C2O4, is a pink to white crystalline material that absorbs moisture to form the dihydrate. It precipitates as the tetrahydrate on reaction of cobalt salt solutions and oxaUc acid or alkaline oxalates. The material is insoluble in water, but dissolves in acid, ammonium salt solutions, and ammonia solution. It is used in the production of cobalt powders for metallurgy and catalysis, and is a stabilizer for hydrogen cyanide. 

Cobalt porphyrin complexes are involved in the chain transfer catalysis of the free-radical polymerization of acrylates. Chain transfer catalysis occurs by abstraction of a hydrogen atom from a grow ing polymer radical, in this case by Co(Por) to form Co(Por)H. The hydrogen atom is then transferred to a new monomer, which then initiates a new propagating polymer chain. The reaction steps are shown in Eqs. 12 (where R is the polymer chain. X is CN), (13), and (14)." ... 

Liu HY, Abdalmuhdi I, Chang CK, Anson FC. 1985. Catalysis of the electroreduction of dioxygen and hydrogen peroxide by an anthracene-linked dimeric cobalt porphyrin. J Phys Chem 89 665. 

Catalysis. Beitel et al. (1997) have employed RAIRS to study in situ the co-adsorption behaviour of CO and hydrogen on single-crystal cobalt (0001) catalysts at pressures up to 300mbar and temperatures between 298 and 490 K. The behaviour of these adsorbates is of considerable importance in relation to their commercial importance as catalysts for the Fischer-Tropsch reaction in the... 

Guczi, L., Stefler, G., Geszti, O., Koppany, Zs., Molnar, E., Urban, M., and Kiricsi, I. 2006. CO hydrogenation over cobalt and iron catalysts supported over multiwall carbon nanotubes Effect of preparation. Journal of Catalysis 244 24—32. 

In another procedure [522] the sample of seawater (0.5-3 litres) is filtered through a membrane-filter (pore size 0.7 xm) which is then wet-ashed. The nickel is separated from the resulting solution by extraction as the dimethylglyoxime complex and is then determined by its catalysis of the reaction of Tiron and diphenylcarbazone with hydrogen peroxide, with spectrophotometric measurement at 413 nm. Cobalt is first separated as the 2-nitroso-1-naphthol complex, and is determined by its catalysis of the oxidation of alizarin by hydrogen peroxide at pH 12.4. Sensitivities are 0.8 xg/l (nickel) and 0.04 xg/l (cobalt). 

With cobalt catalysts, hydroformylation of ethyl cinnamate gave 91% of the hydrogenation product ethyl hydrocinnamate (15) and only 8% of the expected lactone, 16 (72). However, rhodium catalysis was effective in directing the reaction in favor of hydroformylation (70). The comparative results obtained with cobalt and rhodium are outlined in Table XXV. 

IT -cyclopentad ienyldicar bony 1 cobalt, CpCo(C0)2 This material is active in the hydrogenation of CO to saturated linear hydrocarbons and appears to retain its "homogeneous", mononuclear character during the course of its catalysis. 

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