Cobalt perchlorate complexes

The cobalt complex is usually formed in a hot acetate-acetic acid medium. After the formation of the cobalt colour, hydrochloric acid or nitric acid is added to decompose the complexes of most of the other heavy metals present. Iron, copper, cerium(IV), chromium(III and VI), nickel, vanadyl vanadium, and copper interfere when present in appreciable quantities. Excess of the reagent minimises the interference of iron(II) iron(III) can be removed by diethyl ether extraction from a hydrochloric acid solution. Most of the interferences can be eliminated by treatment with potassium bromate, followed by the addition of an alkali fluoride. Cobalt may also be isolated by dithizone extraction from a basic medium after copper has been removed (if necessary) from acidic solution. An alumina column may also be used to adsorb the cobalt nitroso-R-chelate anion in the presence of perchloric acid, the other elements are eluted with warm 1M nitric acid, and finally the cobalt complex with 1M sulphuric acid, and the absorbance measured at 500 nm. 

The use of the perchlorate anion to precipitate the cobalt complex to determine the yield [1] is deprecated on the grounds of potential hazard [2], though it was not found possible to cause the salt to detonate by pounding, but it will bum if ignited. A spectroscopic assay method is suggested as an alternative to precipitation [3],... 

In addition, a few other publications also address this issue of ballistic modification of composite propellants. The cobalt, nickel and zinc hexammine perchlorates have been studied by Gurdip Singh and coworkers for this purpose. The generated data indicate that cobalt complex accelerates burn rate three-fold when used at 2% level in HTPB-AP-based composite propellant [277]. Another study on transition metals (copper, iron, cobalt and nickel) salts of NTO as BRMs for HTPB-AP-based... 

The two halves (266) and (267) were connected as shown in Scheme 20 by condensation of the sodium salt of (266) with the iminoether function in (267) to give the tetracyclic substance (280). Chelation with nickel(II) ions, followed by treatment with butoxide, gave the corrin perchlorate (265 M = Ni), and the cobalt complex was similarly prepared. 

Fig. 10.24. The methyl multiplet in the NMR spectrum of the cobalt complex. (B) The separation of the methyl signals after addition of excess europium perchlorate.

The interaction of the free ligand with cobalt(II) perchlorate in the presence of AgC104 as a precipitant in the nitromethane-methanol mixture made it possible to isolate the [Co(diME l,3pnsar-S6)](C104)3 clathrochelate. The reduction of this clathrochelate with sodium dithionate led to the formation of a cobalt (II) complex that readily produced a free sarcophagine [147],... 

Recent work by Sykes (33) deals with the kinetics of the reduction of the complex (p-2) by ferrous ion in aqueous solution, and gives some evidence for the protonation of the peroxo bridge in acid solution. Other kinetic work, dealing with the oxidation of Co (III) perchlorate by H2O2, has been interpreted in terms of a dimeric cobalt complex species bridged by oxygen (I). 

Tetraammine(carbonato)cobalt(III)] perchlorate (5.74 g, 0.020 mole) is dissolved in 30 mL of 3 M perchloric acid at room temperature with stirring. The carbonato complex dissolves rapidly evolving carbon dioxide. After 5 minutes the solution is filtered and cooled with ice. To the cold (approximately 5°)... 

O4C4H2, Acetylenedicarboxylic acid cobalt complexes, 23 115 04C H,6, 1,4,7,10-Tetraoxacyclododecane lanthanoid complexes, 23 149 04C1NC 6H , Ammonium, tetrabutyl-, perchlorate, 24 135... 

Recently, the complexation of cobalt with 2,2 -dipyridyl-2-pyridylhydrazon at pH 5-8 and its extraction from sea water and brines into iso-amyl alcohol has been recommended. The cobalt complex can be back-extracted into dilute perchloric acid 76). 

To a suspension of 1.17 g (0.001 mole) of [Bal KClO in 800 mL of methanol, in a 2-L round-bottomed flask fitted with a reflux condenser, is added 2.2 g (0.006 mole) of solid cobalt(U) perchlorate hexahydrate. The mixture is gently refluxed until the Ba(II) complex has completely dissolved, which may take two to three days. After the solution becomes clear, the reflux should be continued for an additional two hours. The orange solution is then concentrated to a volume of about SO mL by rotary evaporation and then set aside in a beaker to crystallize. The orange crystals which separate are filtered, washed with cold methanol, and dried in air. Yield 60%. Anal. Calcd. for C HmOuNgC Co C, 44.60 H, 3.74 N, 11.15. Found C, 44.26 H, 3.61 N, 11.00. 

---