Vanadous chloride

Vanadlum-chlorid, n. vanadium chloride, specif. vanadium(III) chloride, VCI3. -chloriir, n. vanadous chloride, vanadium (IT) chloride, VClj. -eisen, n. ferrovanadium. 

Aqueous solutions of vanadous chloride (vanadium dichloride) are prepared by reduction of vanadium pentoxide with amalgamated zinc in hydrochloric acid [213], Reductions are carried out in solution in tetrahydrofuran at room temperature or under reflux. Vanadiiun dichloride reduces a-halo ketones to ketones [214], a-diketones to acyloins [215], quinones to hydroquinones [215], sulfoxides to sulfides [216] and azides to amines [217] (Procedure 40, p. 215). 

Lithium aluminum hydride reduced )J-azidoethylbenzene to j8-aminoethyl-benzene in 89% yield [600], The azido group was also reduced with aluminum amalgam (yields 71-86%) [149], with titanium trichloride (yields 54-83%) [601], with vanadous chloride (yields 70-95%) [217] Procedure 40, p. 215), with hydrogen sulfide (yield 90%) [247], with sodium hydrosulfite (yield 90%) [259], with hydrogen bromide in acetic acid (yields 84-97%) [232], and with 1,3-propanedithiol (yields 84-100%) [602]. Unsaturated azides were reduced to unsaturated amines with aluminum amalgam [149] and with 1,3-propane-dithiol [602]. 

REDUCTION WITH VANADOUS CHLORIDE Preparation of Vanadous Chloride 213]... 

A I M aqueous solution of vanadous chloride (10 ml) is added to a stirred solution of I g of an aryl azide in 10 ml of tetrahydrofuran. After the evolution of nitrogen has subsided the mixture is poured into 30 ml of aqueous ammonia the resultant slurry is mixed with benzene, filtered with suction, and the filter cake is washed with benzene. The benzene layer of the filtrate is separated, the aqueous layer is extracted with benzene, the combined benzene solutions are dried, the solvent is evaporated and the residue is distilled to give 70-95% of the amine. 

Vanadous Chloride, vanadium trichloride, VC13.—This halide is obtained by the action of hydrogen chloride on finely divided vanadium at 300° to 400° C.,e or by heating vanadium tetrachloride to 140° C. in a current of carbon dioxide, which removes the chlorine formed at the same time. It can be conveniently made also by boiling vanadium oxy-trichloride, VOCl3, vanadium tetrachloride, VC14, or a mixture of both, with sulphur, under reflux. The reactions involved axe 7... 

Potassium Vanadicyanide, K3[V(CN)6], is prepared by the addition of excess of concentrated potassium cyanide solution to a concentrated solution of vanadous chloride, VC18 precipitation in the cold with alcohol gives rise to small rhombohedral plates. The solution is not very stable and rapidly becomes turbid, while addition of an acid produces the green colour which is characteristic of the V ion. The complex ion [V(CN)8]" appears, therefore, to be unstable, unlike the corresponding [Fe(CN)e] ", [Cr(CN)J ", and [Co(CN)e] " complex ions. The solution reacts with salts of heavy metals to yield variously coloured precipitates of double cyanides.7... 

Vanadium (III) tris (acetylacetonate) Vanadium, tris (2,4-pentanedionato) Vanadium, tris (2,4-pentanedionato-0,0 -). See Vanadium tris acetyl acetonate Vanadocene dichloride. See Bis (cyclopentadienyl) vanadium dichloride Vanadous chloride. See Vanadium chloride (ous)... 

---