Manganese metavanadate

Manganese Metavanadate, Mn(V03)2.4H20, is a sparingly soluble, dark red powder, obtained by interaction between manganese sulphate and ammonium metavanadate in solution. When the powder is boiled in the precipitating solution, reddish-brown six-sided plates of the anhydrous metavanadate, Mn(V03)2, are produced.8... 

Basic Lead Metavanadate, 8Pb0.2V206.2H20 or Pb0.2Pb(V03)a. 2H20, is obtained as a yellow powder by the action of lead nitrate on an acid manganese vanadate.9... 

The gravimetric estimation of vanadium in alkaline vanadate solutions has also been effected by precipitating as ammonium metavanadate in the presence of ammonium chloride.6 Precipitation is incomplete, however, unless the solution is quite saturated with ammonium chloride 7 the addition of alcohol is recommended.8 Other gravimetric processes which have been investigated include the precipitation of barium pyrovanadate,9 precipitation of silver metavanadate,10 precipitation of manganese pyrovanadate,11 and the use of cupferron.12... 

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. 

At a pH near 6, manganese(II) metavanadate precipitates and does not react further, whereas at a pH near 2, other heteropoly species are formed. Inasmuch as commercial potassium metavanadate is not suitable for the syntheses of the 13-vanadomanganate(IV) and nickelate(IV), directions for the preparation of this compound are included in the syntheses below, which are modified from the method of Flynn and Pope.5 The preparation of the yellow-tinged green reduced form of potassium 13-vanadomanganate(IV) is also included.5... 

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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