Vanadylation

Vanadium oxide trichloride, VOCI3, vanadyl chloride. Readily prepared yellow liquid, b.p. 127 C, formed CK plus heated V2OS plus C. Readily hydrolysed by water. 

Vanadium IV) forms blue VOSO4, (0, 3 and 5H2O), vanadyl sulphate, which forms ranges of double salts, Prepared by SO, reduction of V2O5 in H2SO4. 

As the scheme indicates, the blue vanadyl oxovanadium cation can be (quantitatively) oxidised to vanadium(V) and the latter is reduced... 

Divalent copper, cobalt, nickel, and vanadyl ions promote chemiluminescence from the luminol—hydrogen peroxide reaction, which can be used to determine these metals to concentrations of 1—10 ppb (272,273). The light intensity is generally linear with metal concentration of 10 to 10 M range (272). Manganese(II) can also be determined when an amine is added to increase its reduction potential by stabili2ing Mn (ITT) (272). Since all of these ions are active, ion exchange must be used for deterrnination of a particular metal in mixtures (274). 

The catalyst used in the production of maleic anhydride from butane is vanadium—phosphoms—oxide (VPO). Several routes may be used to prepare the catalyst (123), but the route favored by industry involves the reaction of vanadium(V) oxide [1314-62-1] and phosphoric acid [7664-38-2] to form vanadyl hydrogen phosphate, VOHPO O.5H2O. This material is then heated to eliminate water from the stmcture and irreversibly form vanadyl pyrophosphate, (V(123,124). Vanadyl pyrophosphate is befleved to be the catalyticaHy active phase required for the conversion of butane to maleic anhydride (125,126). 

The use of an organic medium yields an increase in the surface area of the VOHPO O.5H2O (70,126). This increase in surface area is carried over to the resulting vanadyl pyrophosphate phase (123) and is desirable because a concurrent increase in activity toward butane oxidation is observed (70). 

Metal-free, chloroaluminum phthalocyanine [14154-42-8] vanadyl phthalocyanine [13930-88-6], or magnesium phthalocyanines are sufficiently soluble in organic solvents and show enough bleachable absorption at 694.3 nm to serve as repeated Q-switching elements for mby lasers (qv) (180). Phthalocyanines have been used in other lasers as weU (181). 

Vanadium(IV) Oxysulfate. Vanadium(IV) oxysulfate pentahydrate (vanadyl sulfate), VOSO4 -5H20) is an ethereal blue sohd and is readily soluble in water. It forms from the reduction of V20 by SO2 in sulfuric acid solution. Vanadium(III) sulfate [13701 -70-7] ) is a powerful... 

Minor uses of vanadium chemicals are preparation of vanadium metal from refined pentoxide or vanadium tetrachloride Hquid-phase organic oxidation reactions, eg, production of aniline black dyes for textile use and printing inks color modifiers in mercury-vapor lamps vanadyl fatty acids as driers in paints and varnish and ammonium or sodium vanadates as corrosion inhibitors in flue-gas scmbbers. 

Similar complexes are formed between poly(viayl alcohol) and titanium lactate (96,101), titanyl sulfate (102), or vanadyl compounds (103). 

Vanadyl trichloride (VOCI3) [7727-18-6] M 173.3, m-79.5°, b 124.5-125.5°/744mm, 127.16°/760mm, d 1.854, d 1.811. Should be lemon yellow in colour. If red it may contain VCI4 and CI2. Fractionally distil and then redistil over metallic Na but be careful to leave some residue because the residue can become EXPLOSIVE in the presence of the metal USE A SAFETY SHIELD and avoid contact with moisture. It readily hydrolyses to vanadic acid and HCl. Store in a tightly closed container or in sealed ampoules under N2. [Inorg Synth 1 106 1939, 4 80 1953.]... 

Chromyl azide chloride Molybdenum azide pentachloride Molybdenum azide tetrachloride Silver azide chloride Tin azide trichloride Titanium azide trichloride Tungsten azide pentabromide Uranium azide pentachloride Vanadium azide dichloride Vanadyl azide tetrachloride... 

Chemical Designations - Synonyms Trichloroxo vanadium Vanadyl chloride Vanadyl trichloride Chemical Formula VOCI3. 

Chemical Designations - Synonyms Vanadium oxysuliate. Vanadyl sulfate dihydrate Chemical Formula V0S04 2Hi0. 

The yellow colored vanadyl(V) ion is transformed to the blue vanadyl(IV) ion by reaction with redudng agents. 

The 4-4 oxidation state, which for Nb and Ta is best represented by their halides, is most notable for the uniquely stable VO + (vanadyl) ion which retains its identity throughout a wide variety of reactions and forms many complexes. Indeed it is probably the most stable diatomic ion known. The M ions have only slightly smaller radii... 

In the higher oxidation states partially hydrolysed species dominate the aqueous chemistry, the most important being the oxovanadium(IV), or vanadyl, ion This gives the sul-... 

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