Iron vanadate

Anthraquinone is the primary product of the oxidation of anthracene over V2Os-based catalysts. The reaction is very selective and high yields of anthraquinone are possible due to its relatively high stability. An iron vanadate catalyst is used in the industrial process and yields of 80—90 mol. % are reported at 320—370°C. Phthalic anhydride, maleic anhydride and carbon oxides are the by-products. 

I. The preparation of a complex mixture of vanadates or of crude vanadium pentoxide or of crude iron vanadate. 

I. The Preparation of a Complex Mixture of Vanadates or of Crude Vanadium Pentoxide or of Crude Iron Vanadate. 

For the treatment of camotite several methods are available. The method recommended by the United States Bureau of Mines2 is as follows The ore is leached with concentrated nitric acid at 100° C., neutralised with caustic soda, and barium chloride and sulphuric acid added to the solution to precipitate the radium as barium-radium sulphate. The precipitate settles in three or four days, after which time the clear liquid is decanted into tanks and is treated with excess of boiling sodium carbonate solution in order to precipitate any iron, aluminium and chromium present. The solution now contains sodium uranyl carbonate and sodium vanadate. It is nearly neutralised with nitric acid, and caustic soda is added in sufficient quantity to precipitate the uranium as sodium uranate. After filtering, the remaining solution is neutralised with nitric acid and ferrous sulphate added, whereupon iron vanadate is thrown down. By this method it is claimed that 90 per cent, of the radium, all the uranium, and 50 per cent, of the vanadium in the camotite are recovered. 

Iron Vanadate is, metallurgically, the most important vanadate. Precipitation of a solution of a vanadate with ferrous sulphate gives rise to a precipitate of indefinite composition, ortlio-, pyro-, meta-, and perhaps a poly-vanadate being present, as well as ferric or ferrous oxide. Reduction of the vanadate to a vanadyl salt may also ensue. The precipitate is usually colloidal and carries down with it some sodium vanadate. The dried powder may be either green, yellow, brown, or red the more nearly the precipitate approximates to a red colour the lower is its vanadium content. An iron vanadate has also been prepared by electrolysis of a solution of sodium vanadate between iron poles.1... 

Iron vanadate, FeV04, is a prospective material for lithium rechargeable batteries and in catalysis. In [90] mechanical coactivation of iron and vanadium oxides was used to prepare intimate nanoscale mixture, similar to those prepared by soft chemistry. Reduction of this mixture at the same temperature and oxygen partial pressure conditions as of soft chemistry products (500°C and 10 Pa) leads to formation of a nanometric vanadium ferrite with the only spinel phase. The characterization of the powders thus prepared was perfomed by X-ray diffraction, SEM, IR spectrometry, thermogravimetry and colourimetry. It was shown that the homogeneity of grain size and chemical composition is achieved if the initial oxides have similar grain size. 

A catalyst formed from iron vanadate and iron oxide supported on asbestos fibers has been proposed for the oxidation of toluene in vapor phase.104... 

Although little experimental data is available, numerous patents have been issued for the vapor phase catalytic oxidation of various other derivatives containing the benzene nucleus, as well as heterocyclic compounds Thus, fluorene (diphenyl methane) is oxidized to fluorenone with air in the presence of a catalyst containing iron vanadate or other suitable metal salt of the fifth or sixth group of the periodic system at a temperature of 360° to 400°.1,2 Maleic acid and anhydride are formed by the catalytic oxidation of compounds of the furan series, such as furan, furfural alcohol, furfural, methyl furfural, hydroxymethylfurfural, pyromucic acid or mixtures, with air over catalysts of molybdenum, vanadium, or other metals.133 Dimethyl benzaldehyde is formed by oxidizing pseudocumene with air at 550° C. in the presence of a tungsten oxide catalyst. Molybdenum, vanadium, or tantalum oxide catalysts may also be used to form aromatic aldehydes from o-, m-, or p-xylenes, mesitylene, p-cymene, or o-chlorotoluene by air oxidation. Times of contact of 0.3 to 0.4 seconds... 

---