Vanadium oxide nitrate

Discussion. Molybdates [Mo(VI)] are quantitatively reduced in 2M hydrochloric acid solution at 60-80 °C by the silver reductor to Mo(V). The reduced molybdenum solution is sufficiently stable over short periods of time in air to be titrated with standard cerium(IV) sulphate solution using ferroin or /V-phenylanthranilic acid as indicator. Nitric acid must be completely absent the presence of a little phosphoric(V) acid during the reduction of the molybdenum(VI) is not harmful and, indeed, appears to increase the rapidity of the subsequent oxidation with cerium(IV) sulphate. Elements such as iron, copper, and vanadium interfere nitrate interferes, since its reduction is catalysed by the presence of molybdates. 

VANADIUM (V) OXIDE NITRATE AND CHROMIUM (VI) OXIDE NITRATE... 

Chromium(VI) oxide nitrate and vanadium(V) oxide nitrate were first prepared by Schmeisser and Lutzow by the reaction of chromium(VI) oxide and vanadium(V) oxide with nitrogen(V) oxide. The nitrogen(V) oxide was prepared in the solid state by dehydration of fuming nitric acid with phosphorus(V) oxide. The method described below simplifies the preparation of anhydrous nitrogen(V) oxide and shortens significantly the time required. The products obtained can be protected from hydrolysis by totally excluding water from the all-glass system. 

The same procedure is used for the preparation of chro-mium(VI) oxide nitrate except that the nitrogen(V) oxide is distilled into the reaction vessel under an atmosphere of dry oxygen (not ozone) to prevent the formation of any perchromic acid derivatives. The initial weight of anhydrous chromium(VI) oxide is 30 g. (0.30 mol). The reaction proceeds much faster than in the case of the vanadium compound, so that the reaction time need be only 24 hours. 

Vanadium (V) oxide nitrate is a pale yellow, viscous liquid which boils at 64 to 65° at 0.7 mm. Hg pressure. It is soluble in carbon tetrachloride. It reacts immediately with water to form nitric acid and a dark red-brown precipitate of impure vanadium(V) oxide. It is a powerful oxidizing agent and ignites most hydrocarbons with which it comes in contact. It attacks paper, wood, and rubber in the same manner as fuming nitric acid does. It can be stored for considerable lengths of time in a sealed ampul in the absence of light and moisture, and it can be purified by vacuum distillation. 

Vanadium(V) oxide nitrate and chromium(VI) oxide nitrate, synthesis 22. 

The selective oxidation of NH3 to NO is catalyzed by Pt/Rh. Called Ostwald reaction, it runs at high temperatures and is an important step in the conversion of nitrogen to nitrates via ammonia. Another catalytic oxidation process in inorganic chemistry is the oxidation of SO2 to SO3 to produce sulfuric acid. Platinum or vanadium oxide are the preferred catalysts. The catalyst has to be able to dissociate oxygen, and bulk sulfate formation, deactivating the catalyst, has to be suppressed. 

Dining outgassing of scrap uranium-aluminium cermet reactor cores, powerful exotherms led to melting of 9 cores. It was found that the incident was initiated by reactions at 350°C between aluminium powder and sodium diuranate, which released enough heat to initiate subsequent exothermic reduction of ammonium uranyl hexafluoride, sodium nitrate, uranium oxide and vanadium trioxide by aluminium, leading to core melting. 

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 spray method was used to produce alumina pigments doped with Cr, Mn, and Co. In these experiments, Al(.vec-OBu)3 was mixed with solutions of the corresponding metal nitrates in. veobutoxide, the resulting liquids were nebulized, and then the droplets were hydrolyzed (76). The major purpose of these studies was to obtain inorganic pigments and to evaluate their color properties by altering the amount of dopants in the aluminum oxide matrix. For the same reason, the vanadium... 

The purification of the alkali hydroxides.—Numerous impurities have been reported in commercial sodium and potassium hydroxides. Several have commented on the presence of peroxide, particularly in caustic potash.19 Various salts—carbonate, sulphate, nitrate, nitrite, chloride, and phosphate—as well as alumina, silica, organic matters, and metal oxides—e.g. arsenic, vanadium, iron, etc., have been reported. More or less of the other alkalies may also be present. 

Preparation of Anhydrous Dioxovanadium Nitrate (VO2NO3). Prepare 7-10 ml of liquid nitrogen(IV) oxide (see p. 141). Mix the nitrogen(IV) oxide with 5-7 cm of dry acetonitrile in a test tube (see Fig. 92a). Add 0.3-0.5 g of metallic vanadium preliminarily crushed in a porcelain mortar to this mixture. Close the test tube with a stopper provided with a calcium chloride tube containing phosphoric anhydride. 

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