Sodium hydroxylamine monosulfonate

D. Dimethylglyoxime.—The crude biacetyl monoxime, remaining after distilling to 90° and containing about 5 moles of biacetyl monoxime, is added to the sodium hydroxylamine monosulfonate solution (which has been filtered to remove any sediment) and which is contained in a 15-I. flask. It is heated to 70° and allowed to remain warm (with occasional stirring) for several hours (Note 9). The dimethylglyoxime separates in crystals which can be filtered from the solution as soon as it has become cold (Note 10). The crystals are washed with cold water until free of sulfate. The yield of compound melting at 238-240° is 540-575 g-... 

C. Sodium Hydroxylamine Monosulfonate.—In a 12-I. crock are mixed 5 kg. of shaved ice (Note 6) and 569 g. of sodium nitrite (594 g. of the technical 95 per cent quality). Into this is stirred a suspension of sodium bisulfite containing noo g. of available sulfur dioxide (about 1775 g. of technical bisulfite) in 750 cc. of water. Then, beneath the surface of the solution is added, with constant stirring, 150 cc. of glacial acetic acid... 

A classical method of preparing a standard solution of sodium hydroxylamine disulfonate is given here. Some disagreement exists in the literature as to the exact nature of this reagent. Sometimes it is referred to as sodium hydroxylamine monosulfonate [3,4]. 

Note 7) followed by a mixture of 550 cc. of concentrated hydrochloric add (sp. gr. 1.19) with 400 g. of shaved ice (Note 8). The entire solution should always remain below o°, further ice being added if there is a tendency for the temperature to rise. The solution should now become acid to Congo Red paper and contain 6 or more moles of the sodium hydroxylamine disulfonate, which rapidly hydrolyzes to an acid solution of the monosulfonate. 

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