Tungstic oxide

Method 1 siHca—alumina, siHca, alumina, titania, tungstic oxides, phosphates, 2eoHtes, and clays. 

The kinetics of the ethylene hydration reaction have been investigated for a tungstic oxide—siHca gel catalyst, and the energy of activation for the reaction deterrnined to be 125 kJ/mol (- 30 kcal/mol) (106,120). The kinetics over a phosphoric acid-siHca gel catalyst have been examined (121). By making some simplifying assumptions to Taft s mechanism, a rate equation was derived ... 

Tungstic oxide —- Hydrogen reduction — Tungsten metal powder Figure 5.39 Processing of tungsten resources. 

The separation of the tungstic oxide and silica in the anhydride is effected by the method of Perillon8 wherein the tungstic oxide is volatilized in a current of gaseous hydrogen chloride. The silica is then volatilized by means of hydrofluoric and sulfuric acids. Since W03 cannot be collected readily, its weight is determined by difference. 

Fig. 6.15. Resuspension of submicrometre particles of tungstic oxide up to 100 h - wind tunnel operated at 12 m s-1 after 100 h - periods of natural weathering (hatched) in intervals between further operation of wind tunnel.

Tungstic oxide at 350° is reduced to a blue oxide which has a dehydrating effect and ethylene results as well as aldehyde and acetic acid. 

Procedure Digest the tungstic oxide with 40 cc. of 15 N NH4OH for 10 minutes at 50°. Pour off the clear solution, and if a solid residue is left digest it repeatedly with 5-cc. portions of the NH4OH, adding the extract to the main solution. Filter, if necessary, directly into the evaporating dish. Let stand at about 80° until dry. Save the needle shaped crystals in a 2-ounce, cork-stoppered bottle. 

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