Cobalt carbonate, solubility-product

Cobalt(II) complexes of three water-soluble porphyrins are catalysts for the controlled potential electrolytic reduction of H O to Hi in aqueous acid solution. The porphyrin complexes were either directly adsorbed on glassy carbon, or were deposited as films using a variety of methods. Reduction to [Co(Por) was followed by a nucleophilic reaction with water to give the hydride intermediate. Hydrogen production then occurs either by attack of H on Co(Por)H, or by a disproportionation reaction requiring two Co(Por)H units. Although the overall I easibility of this process was demonstrated, practical problems including the rate of electron transfer still need to be overcome. " " ... 

Tris (ethylenediamine) cobalt (III) chloride was first prepared by Werner.1 Resolution was effected through the chloride d-tartrate which was obtained by allowing the chloride (1 mol) to react with silver d-tartrate (1 mol). The correct ratio of chloride ion to tartrate ion is important and this has meant that it was necessary to isolate the pure solid chloride, the synthesis of which has been described by Work.2 In the present method the less soluble diastereo-isomer is isolated directly and the expensive and unstable silver d-tartrate is replaced by barium d-tartrate. The addition of activated carbon ensures rapid oxidation of the initial cobalt (II) complex and eliminates small amounts of by-products of the reaction. 

Liquid propylene, gaseous carbon monoxide and hydrogen, and a soluble cobalt catalyst are fed to a high-pressure catalytic reactor. The reactor effluent goes to a flash tank, where all of the solution constituents are vaporized except the catalyst, which is recycled to the reactor. The reaction products are separated from unconsumed reactants in a multiple-unit process, and the product stream, which contains both butyraldehyde and /i-butanol, is subjected to additional hydrogenation with excess hydrogen, converting all of the butyraldehyde to butanol. 

A solution of 14 g (0.05 mole) of the potassium salt of c/s-diammine-di(carbonato)cobaltate(III) in 150 mL of cold water is charged on a column containing Dowex 50W-X8 resin in the Li+ form (100-200 mesh, 7 cm x 15 cm). With the addition of cold water, a blue solution effuses from the column. To the effluent is added 3 g of ammonium carbonate and the solution is concentrated to 50 mL under reduced pressure at 35°. The concentrated solution is filtered and kept in a refrigerator until blue crystals of lithium m-diammi-nedi(carbonato)cobaltate(IQ) deposit. This crude product is recrystallized from water, collected on a filter, washed with cold water, ethanol, and diethyl ether, and finally dried under vacuum. The yield is 3 g. Anal. Calcd. for Li[Co(C03)2(NH3)2] C, 10.92 H, 2.75 N, 12.73. Found C, 10.92 H, 3.04 N, 12.66. The solubility of this salt in water is considerably lower than that of the potassium salt. 

S-Leucinato-JV, 0) bis [2,2,6,6-tetramethyl-3,5-heptanedionato -0,0 ) -cobalt(III).—An analogous reaction between the corresponding 2,2,6,6-tetramethylheptanedionate (or dipivaloylmethanate, dpm), but at much lower concentrations due to limited solubility in water, provided a 15% yield of the intermediate product and a 25% yield of the final Co(leu)(dpm)2 product. FT-NMR carbon-13 results are in agreement with the formulation given. 

Cyclopentadienyl)bis(trimethyl phosphite)cobalt(I) is a red-brown crystalline low-melting product that is air sensitive and should be stored under an inert atmosphere at 10-20°. It is soluble in hydrocarbon solvents, but decomposes in chloroform and carbon tetrachlori. The HNMR spectrum... 

All these complexes are dark colored, more or less soluble in hydrocarbons, air sensitive, especially in solution. Their thermal decomposition, beginning usually at 100-140 yields carbon monoxide, hydrocarbons and a cobalt sulfide containing a solid residue, when sulfur is lost in form of volatile products, when the S Co ratio in the complex exceeds one. The cobalt-sulfur bond seems therefore to be rather strong, irrespective the character of the bond as is seen from comparing Co (CO] S and Co (COysxSCH2C Hg). 

Post et al. (1989) prepared a series of iron and cobalt-base catalysts. The studies were performed in a fixed-bed micro reactor system at temperatures in the range 473—523 K. Variation of catalyst particle size in the range 0.2-2.6 mm showed that the conversion of synthesis gas decreases considerably when the average particle size was increased. Under reaction conditions, the major part of the hydrocarbon product would be the liquid. The liquid would fill the pores of the catalyst so that transport of hydrogen and carbon monoxide to the reactive sites occurred by diffusion of these reactants through this Hquid medium inside the pores. The apparent effective diffusivity D, can be related to the molecular diffusivity, (H2) and solubility, H (H2) of hydrogen in the paraffinic liquid by Eq. (49) ... 

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