Copper metavanadate

Copper Metavanadate.—Addition of copper sulphate solution to sodium metavanadate throws down a precipitate which consists mainly of copper metavanadate, which is light yellow. The precipitate may, however, be green or blue, because its composition varies considerably. Copper metavanadate can also be produced eleetrolytically. On being fused at a high temperature in a graphite crucible it forms copper and vanadium carbide.10... 

Usually the nitric acid/amine interaction is more dangerous when impurities that can play a catalytic role are present. This goes for metal oxides such as copper oxides, iron (III) oxide and divanadium pentoxide. Salts such as sodium or ammonium metavanadates, iron trichloride, alkaline chromates and dichromates, cyanoferrates and alkaline or nitrosopentacyanoferrates can also act as catalysts. 

The effect of inorganic additives upon ignition delay in anilinium nitrate-red finning nitric acid systems was examined. The insoluble compounds copper(I) chloride, potassium permanganate, sodium pentacyanonitrosylferrate and vanadium(V) oxide were moderately effective promoters, while the soluble ammonium or sodium metavanadates were very effective, producing vigorous ignition. 

The effects of various metal oxides and salts which promote ignition of amine-red fuming nitric acid systems were examined. Among soluble catalysts, copperQ oxide, ammonium metavanadate, sodium metavanadate, iron(III) chloride (and potassium hexacyanoferrate(II) with o-toluidine) are most effective. Of the insoluble materials, copper(II) oxide, iron(III) oxide, vanadium(V) oxide, potassium chromate, potassium dichromate, potassium hexacyanoferrate(III) and sodium pentacyanonitrosylferrate(II) were effective. 

Turpentine and fuming nitric acid do not ignite on contact in absence of added catalysts (fuming sulfuric acid, iron(III) chloride, ammonium metavanadate or copper(II) chloride). 

Copper sulphate solution green precipitate with metavanadates. Pyro-vanadates give a yellow precipitate. 

The crystalline hydrates are generally speaking vitriols of the composition M(II)S04 7 H2O. Like the stable manganese vitriol, copper vitriol crystallises with 5 molecules of water of crystallisation per metal ion. Mixed colors can appear if ammonium metavanadate is used as the starting material in test tube 1 because of the presence of several oxidation states of vanadium. 

Commercially, cyclohexane is oxidized to a mixture of cyclohexyl hydroperoxide, cyclohexanol, and cyclohexanone at 3.5-19 X 10 kP and 400-450 K using a cobalt(II) naphthanate catalyst. The hydroperoxide in this mixture is then decomposed to cyclohexanol and cyclohexanone with a second cobalt catalyst. Adipic acid, the desired end-product of cyclohexane oxidation, is produced by oxidation of the mixture of cyclohexanol and cyclohexanone with 40% HNO3 containing 0.2% of a catalyst consisting of ammonium metavanadate and copper turnings. 

The mixture obtained after initial oxidation is treated with an excess of 60 per cent weight nitric add (nitric add to Ol/One mixture ratio 5/1) in the presence of 0J2 per cent weight of a catalyst consisting of ammonium metavanadate and copper scraps. The reaction is highly exothermic. It is conducted in two reactors in series, in which the reaction medium is maintained at between 60 and 80°C in the fust and 100°C in the second, by external circulation and cooling. Residence time in these two units is approximately 5 and 7 min respectively. If a very pure Ol/One mixture or cydobexanol is employed, the molar yield of adipic acid reaches 92 to 96 per cent. The gases must be separated to remove the nitrogen and N20 and to recycle the NO + N02. 

Vanadium (V) oxide as one of the starting materials is prepared as follows. Ammonium metavanadate is recrystallized at least twice from its hot aqueous solution by adding ammonium chloride. The purified ammonium metavanadate is converted to vanadium(V) oxide by heating it at 350°C. in a porcelain dish. The lower oxides of vanadium which are produced at the same time as that of vanadium(V) are oxidized by heating them with a small amount of nitric acid. The resulting vana-dium(V) oxide is melted in a platijium crucible and crystallized by pouring the melt on a copper plate. 

Sodium metavanadate dyeing mordant, textiles Copper nitrate (ic) dyeing seawater, spotting purposes Fluorescein... 

The mixed cerium oxide samples were prepared by homogenous co-precipitation from aqueous solutions, using IM ammonia solution as base. The metal precursors used were cerium (IV) ammonium nitrate, ammonium metavanadate (V) and copper (II) nitrate or iron (II) nitrate. The concentrations of all the solutions used were O.OIM throughout. The appropriate solutions were mixed in the appropriate ratios, to achieve the desired results. The precipitate was left to stand in the mother liquor for 24h, centrifuged and dried at 373K for 24h. 

Both potassium nitrate (0.5%) and potassium chromate (0.2%) are very effective in carbon dioxide systems, but not with hydrogen sulfide. Use of metavanadate in hot carbonate systems can passivate steel in a carbonate solution only when the bicarbonate content is low. The addition of oxygen to the system increases passivation of mUd steel, but increases corrosion of copper-nickel alloys. 

The ketone/alcohol oil was then oxidized further to adipic acid in a 60% nitric acid solution with an ammonium metavanadate/copper nitrate catalyst at 50°-80°C. Selectivity to adipic acid was more than 95%. A second air oxidation process at 80°-85°C and 6 bar has since been developed. By using a copper ace-tate/manganese acetate catalyst in acetic acid solution, the process has the advantage of avoiding the use of the strongly corrosive nitric acid ... 

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