Chemical elements
    Nitrogen Cycle
    Physical Properties
    Chemical Properties
      Hydrazine Salts
      Sulphonic Derivatives
    Nitric Acid

Sulphonic Derivatives of Hydrazine

The reaction between sulphuryl chloride, SO2Cl2, and dry ammonia gives under various conditions sulphamides and sulphimides. Some of these products were early prepared in an impure state.

In ligroin solution, trisulphimide (see table), sulphomelide (videinfra), and sulphamide are present. After removal of chloride with PbO, the silver salts of these compounds are precipitated in the order given, the last being that of sulphamide, which is then decomposed with the theoretical amount of HCl. The free sulphamide is recrystallised from hot alcohol. Or, the compound may be prepared in chloroform solution, the solvent then distilled, and the residue, dried at 100° C., is mixed with sand and extracted with ethyl acetate.

An entirely different method of making sulphamide by the decomposition of ammonium amido-sulphite has also been described.

The compound crystallises in colourless rhombic tables, melting at 91.5° to 93° C., easily soluble in cold water, hot methyl, or ethyl alcohols.

The molar weight in water corresponds to the formula SO2.N2H4. At 100° C. it is decomposed with evolution of ammonia. In solution it is hydrolysed by acids to ammonium sulphate, by alkalies less completely, to salts of amido-sulphonic acid. The aqueous. solution does not react acid or conduct the electric current, but the hydrogen, while not ionised in solution, can be displaced with formation of salts. Thus the insoluble silver salt is precipitated by double decomposition. Mono- and di-potassium salts, SO2N2H3K and SO2N2H2K2, are obtained by the reaction between the compound and potassium amide in liquid ammonia. Trisulphimide, (SO2NH)3, as a silver salt is the first fraction of the precipitate mentioned above. Esters are also known, but the free compound has only been prepared in solution. It is considered to have the formula

analogous to that of cyanuric acid, (OCNH)3.

The ammonium salt of an isomeric compound, (SO2NH)3, is present in the residues after the distillation of ligroin from the products of the reaction which occurs between SO2 and NH3. The structure is said to be cyclic,

and analogous to that of cyamelide.

Imido-sulphamide (see table) is formed when the silver salt of tri- sulphimide is treated with H2S. It appears as colourless crystals, melting at 160° C., which are soluble in ether, and in water, giving an acid solution from which ammonium, alkali, and silver salts can be obtained by displacement of the imino-hydrogen. It is also made from ammonium carbamate and pyrosulphuryl chloride.

Nitrilo-sulphonic acid or amino-trisulphonate, N(SO3H)3, has long been known in the form of its potassium salt, which is precipitated as crystals when a mixture of 1 mol. of KNO2 and 3 mols. of K2SO3 is allowed to stand:

KNO2 + 3K2SO3 + 2H2O = N(SO3K)3 + 4KOH.

The sodium salt is formed when SO2 is passed into a fairly concentrated solution containing 2 mols. of NaNO2 and 3 mols. of Na2CO3.

It differs from the potassium salt in being more soluble and in crystallising with 5 mols. of water instead of with 2. These salts are hydrolysed quickly into the imido-, more slowly into the amido-, salts, especially in acid solution. Disodium imido-disulphonate is prepared by expelling the SO2 from the above-mentioned sodium nitrilo-sulphonate by a current of air. The solution is then made slightly alkaline with Na2CO3 and evaporated. Sodium sulphate crystallises first, and then NH(SO3Na)2.

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