Frémy's salt

Fremys salt

Fixed

Risk

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Potassium nitrosodisulfonate (also Fremys salt, K2 [ON (SO3 ) 2] ) is the potassium salt of nitrosodisulfonic acid is not known in the free state. It was discovered in 1845 by Edmond Frémy ( 1814-1894 ).

Properties

The orange- yellow colored crystals of Kaliumnitrosodisulfonats dissolve in water with a violet color. In the crystal, the anion is present dimer in aqueous solution, it dissociates into two radical anions (specifically Aminoxyl ). Potassium nitrosodisulfonate is a strong oxidizing agent, which may for example be used in organic chemistry to convert phenols to quinones.

Representation

Nitrosodisulfonate are oxidation products of the prior art also is not in the free state, hydroxylamine -N, N -disulfonic acid. Potassium nitrosodisulfonate obtained on the synthesis of this acid and its oxidation. These added to an ice-cooled aqueous solution of sodium nitrite and sodium with acetic acid to give the corresponding hydroxylamine -N, N- disulfonate forms:

This is oxidized with potassium permanganate to Nitrosodisulfonat in ammoniacal environment:

After filtering off the precipitated manganese dioxide, offsetting the violet solution with potassium chloride and cooling is obtained Fremys salt as an orange- yellow crystals.