Benzeneseleninic acid

white to beige crystalline powder or needles

Benzeneseleninic acid was used as catalyst during the oxidation of sulfides to sulfoxides via ligand coupling on the iodine atom. It was also used in the preparation of 3-methoxy-17a-oxa-D-homoestra-l,3,5(10)-trien-17-one.

Benzeneseleninic acid oxidizes hydrazine or 1,2-disubstituted derivatives to corresponding diazenes.

Reacts violently with hydrazinederivatives (e.g., benzohydrazide). When heated todecomposition it emits toxic fumes of Se.

Add 10% excess of 15M NH3 to the solid acid and stir until the solid dissolves, filter, decolorise with charcoal (2x, Norite) and acidify by slow addition of 6M HCl, filter the solid off and wash it with H2O. Dissolve the acid in the minimum volume of MeOH, and this solution is added dropwise to boiling H2O until cloudiness appears. At this point add 25% more boiling H2O, filter hot (decolorise if necessary) and cool rapidly, with scratching, to 0o. After 30minutes the solid is filtered off and recrystallised as before but with very slow cooling. The colourless needles are filtered off and dried in a vacuum desiccator (CaCl2) before the melting point is measured [McCullough & Gould J Am Chem Soc 71 674 1949]. The HNO3 complex has m 112o. [Beilstein 11 H 422, 11 I 110, 11 III 716.]