Preparation from Vanadium V Oxide

Submitted by Burl E. Bryantt and W. Conard FERNELiusf Checked by Daryle H. Busch,t R. Carl Stoufer,J and Wilmer 

Five grams of technical vanadium(Y) oxide (ca. 0.03 mol) is placed in a 200-ml. round-bottomed flask which is attached to a reflux condenser through a ground-glass joint. One hundred milliliters of commercial acetylacetone (ca. 0.98 mol)jj is added, and the mixture is refluxed gently for 24 hours. The suspension is filtered while hot,1f and the filtrate is cooled. About 5 g. of product separates as tiny blue crystals. The remaining acetylacetone is removed by evaporation in a stream of air. The solid product is washed with acetone and ethyl ether and dried at 110°. The yield is 10 g. (68%). Anal. Calcd. for V0(C6H702)2 C, 45.28 H, 5.28 V, 19.25. Found C, 45.09 H, 5.33  

U Resinous material may form and clog the filter. The addition of a Bmall quantity of acetone before filtration alleviates this difficulty. The nature of the organic oxidation product is indefinite and is represented in an idealized fashion in the equation as (CHiCO) jCO. 

Material of analytical-reagent purity is obtained by recrystallization from acetone or acetylacetone, with a recovery of 50 to 80%. 

Vanadium(IV) oxy(acetylacetonate) is a blue to blue-green compound, crystallizing in the monoclinic system with refractive indexes of a, 1.520 0, 1.676 y, 1.739.7 The compound was originally believed to be a 1-hydrate but is now known to be anhydrous. It forms addition compounds with pyridine, methylamine, and other amines.8 Vanadium(IV) oxy(acetylacetonate) decomposes at elevated temperatures and has no definite melting point. The compound is soluble in ethanol, benzene, chloroform, and acetylacetone but is only moderately soluble in acetone or ethyl ether. 

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Preparation from Vanadium (V) Oxide through Prior Reduction to Oxovanadium(IV) Ion... 

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