DISODIUM NITROSODISULFONATE

OXIDATION WITH THE NITROSODISULFONATE RADICAL. 1. PREPARATION AND USE OF DISODIUM NITROSODISULFONATE TRI-METHYL-p-BENZOQUINONE, 52,... 

B. Trimethyl-p-benzoquinone. The aqueous solution containing approximately 0.17 mole of disodium nitrosodisulfonate is placed in a 1-1. round-bottomed flask fitted with a mechanical stirrer, a thermometer, and an ice bath. A solution of 10.Og. (0.0734 mole) of 2,3,6-trimethylphenol (Note 7) in 100 ml. of heptane is added to the reaction flask and the resulting mixture... 

A. Disodium Nitrosodisulfonate. In a 1-1. resin kettle, equipped with a mechanical stirrer, a thermometer, a gas-inlet tube suspended about 0.5 cm. above the bottom of the vessel, and an ice-cooling bath, are placed 15.0 g. (0.217 mole) of sodium nitrite (Note 1), 16.8 g. (0.200 mole) of sodium bicarbonate (Note 1), and 400 g. of ice. Sulfur dioxide (25.6 g. or 0.40 mole, Note 2) is passed into the cold, initially hetero-gcmcous mixture with stirring over a period of 40 minutes. Near the end of the sulfur dioxide addition, the light brown color of the reaction mixture fades almost completely. The resulting colorless to pale yellow solution of disodium hydroxyl-aminedisulfonato (Note 3), which has an approximate pH of 4,... 

The nitrosodisulfonate salts, particularly the dipotassium salt called Fremy s salt, are useful reagents for the selective oxidation of phenols and aromatic amines to quinones (the Teuber reaction). - Dipotassium nitrosodisulfonate has been prepared by the oxidation of a hydroxylaminedisulfonate salt with potassium permanganate, " with lead dioxide, or by electrolysis. This salt is also available commercially. The present procedure illustrates the electrolytic oxidation to form an alkaline aqueous solution of the relatively soluble disodium nitrosodisulfonate. This procedure avoids a preliminary filtration which is required to remove manganese dioxide formed when potassium permanganate is used as the oxidant. " ... 

Solutions of the nitrosodisulfonate salts are most stable in weakly alkaline solutions (pH 10) and decompose rapidly when the solution is acidic or strongly alkaline. The solid- dipotassium nitrosodisulfonate (Fremy s salt) has been reported to procedures involving the use of substantial quantities of the dry solid salt may be hazardous. In the present procedure, separation and use of the solid salt is avoided since the disodium nitrosodisulfonate is formed and used in aqueous solution. In this procedure, 2 moles of the preformed nitrosodisulfonate salt are consumed in the oxidation of one mole of the phenol to the benzoquinone huivative. The submitters report that only one molar equivalent of the nitrosodisulfonate salt is required if the electrochemical oxidation is carried out in the presence of a heptane solution of the phenol. 

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