Cobalt nitrate decomposition

FIGURE 1.4 Decomposition of (a) cobalt nitrate solution and (b) cobalt nitrate-mannitol solution, measured by TGA and DTA. 

Recently, it has been reported that a novel calcination procedure relying on nitric oxide gas in lieu of air also results in smaller cobalt crystallites over silica supports.15 17 The idea is to use a less oxidative gas to prevent rapid decomposition of the nitrate precursor during thermal nitrate decomposition, which has been observed when 02 is present.17 As a result, the mobility of the precursor on the oxide carrier surface is hindered, resulting in a smaller average Co oxide cluster... 

E. P. Alvarez 2 found that the pemitrates react with soln. of lead acetate (white precipitate), silver nitrate (white precipitate), mercurous nitrate (white precipitate with rapid decomposition), mercuric chloride (red precipitate), copper sulphate (blue precipitate), zinc and cadmium sulphates (white precipitate), bismuth nitrate (white precipitate), gold chloride (slight effervescence and escape of oxygen), manganous chloride (pink precipitate), nickelous chloride or sulphate (greenish-white precipitate), cobaltous nitrate and chloride (pink precipitate), ferrous sulphate (green or bluish-green precipitate), ferric chloride (red ferric hydroxide), and alkaline earth chlorides (white precipitates). The precipitates are all per-salts of the bases in question. 

The temperature required for the reduction of cobalt oxides to the metal appears to be somewhat higher than for the reduction of nickel oxide. The catalyst with a higher catalytic activity is obtained by reduction of cobalt hydroxide (or basic carbonate) than by reduction of the cobalt oxide obtained by calcination of cobalt nitrate, as compared in the decomposition of formic acid.91 Winans obtained good results by using a technical cobalt oxide activated by freshly calcined powdered calcium oxide in the hydrogenation of aniline at 280°C and an initial hydrogen pressure of 10 MPa (Section... 

Calcination of two samples at 500°C on air is accompanied by both decomposition of cobalt nitrate and water removal. Figure 2 demonstrates the Cu " ESR spectra of Samples 1 and 3 calcined at 500°C for 2 h. The signals are identical to those... 

Thermal decomposition is the process wherein the structure of the catalyst is formed by the heat treatment of the precursor after volatile components are decomposed or chemical water associated with the lattice structure of the solid is removed. Examples of such a phenomenon are the decomposition of metal nitrate, hydroxide, carbonate, chloride, sulfate, phosphate, hydroxy salts, or oxy salts to corresponding oxides. The following equation shows the decomposition of cobalt nitrate coupling with partial oxidation of Co ... 

The sample of C03O4 investigated (5) was prepared by the thermal decomposition of cobalt nitrate followed by careful washing with water. 

Bimetallic Co(Ni)-Mo carbides can also be synthesized due to the decomposition of precursors (metal-hexamethylenetetramine complexes) in an inert atmosphere [9, 10], This is a simple one-stage method of the formation of double C03M03C and CogMogC carbides [11], In [12], the Co Moi j oxides prepared from aqueous solutions of cobalt nitrate and ammonium heptamolybdate were carbonized in a flow of pure methane and hydrogen (20% CH4/H2 mixture) to form double carbides. 

To a stirred solution of 5.70g (21.1 mmol) of 4,4.5,5-tetramethyl-2[(5)-(A)-3-(trimethylsilyloxy)-l-bulenyl]-l, 3,2-dioxaborolane in 130 mL of petroleum ether (bp 40-60 C) are added ca. 20 mg of cobalt(II) nitrate hexahydrale followed immediately by 2.75 g (23.1 mmol) of freshly distilled thionyl chloride. Slow evolution of sulfur dioxide ceases after 4h. The mixture is then filtered and concentrated in vacuo at r.t. to give crude 15, which is taken up in 50 mL of petroleum ether and washed with 30-mL portions of buffer (pH 5) until the pH is constant. 100 mL of brine are added to the organic phase and the pH is adjusted to 7 by addition of sat. aq NaHCO,. The pH should not exceed 7, otherwise decomposition ensues. The phases are separated and the organic phase is dried with MgS04 and concentrated at r.t. to give 15 yield 4.39 g (96%) Contact of 15 with metal surfaces should be avoided. 

Alone, or Metals, or Metal compounds Mellor, 1940, Vol. 8, 327 1967, Vol. 8, Suppl. 2.2, 84, 96 It is an explosive of positive oxygen balance, less stable than ammonium nitrate, and has been studied in detail. Stable on slow heating to 300°C, it decomposes explosively on rapid heating or under confinement. Presence of zinc, copper, most other metals and their acetylides, nitrides, oxides or sulfides cause flaming decomposition above the m.p. (70°C). Commercial cobalt (cubes) causes an explosion also. 

Catalysts were prepared by impregnation using cobalt (ii) nitrate. Co/A1203 was the most the active and selective catalyst. Suppresses the ethanol decomposition and CO methanation reactions... 

In a one-pot process for the preparation of the complexes from cobalt(II) nitrate, which is converted into the tetracarbonyl anion by the standard procedure [9], higher yields of (2) are claimed (R = Cl, 42% R = Br, 36% R = H, 30%) using cetyltrimethylammonium bromide as the catalyst. It is known that the cluster compounds are unstable under basic conditions and it was noted that, for example, in the preparation of the chloro compound, extended reaction times (4.5 hours) resulted in the total decomposition of the product [10]. 

The chloride may be prepared in similar manner to the nitrate from cobaltous chloride, and the other salts from the nitrate by double decomposition with soluble salts of the respective acids. All the salts of the series are soluble in water, neutral in reaction, and have a yellowish-brown colour. 

The increase in the rate of decomposition under the influence of added Cr203 and K2Cr207 is shown on Figs. 171 and 172 respectively.lt has been found that an increase of the rate occurred only at temperatures near to the melting point of the samples. Guiochon [17] also found that cobalt salts increase the rate of thermolysis of ammonium nitrate. Other mineral salts (of manganese, nickel and copper) have a similar but much weaker action. A large number of salts of other metals are without any noticeable action. 

---