226 EDWARD DIVERS AND TAMEMASA HAGA ; 



closely, about one-tenth of the hydroxy lamine always becomes am- 

 monia, the solution being cold (not much exceeding 25° by the 

 heat of the reaction) and of moderate concentration. When the 

 solution, a day after preparing it, is distilled with potassium hydroxide, 

 it gives a tenth of the nitrogen as ammonia, whether sulphate or 

 hydrochloride has been used, or whether or not, along with either of 

 these salts, just enough sodium carbonate has been added to combine 

 with its acid, leaving the hydroxylamine free, or whether more sodium 

 carbonate has been added and converted into metasulphite. If, instead 

 of at once distilling off the ammonia, the solution, deprived of its 

 excess of sulphur dioxide, is heated for some hours at 150-00°, so as to 

 hydrolyse all amidosulphonic acid, and only then distilled with potas- 

 sium hydroxide, the ammonia, obtained is closely equivalent to the 

 hydroxylamine taken. Therefore, no nitrogen has been lost as gas. 

 The stability of amidosulphonic acid is such that, under the stated 

 circumstances, it is certain that only quite insignificant decomposition 

 of the acid can occur, and, therefore, that nearly all the ammonium 

 hydrogen sulphate comes directly from hydroxylamine, sulphur 

 dioxide, and water. 



Although the action of sulphur dioxide upon hydroxylamine is 

 not affected by the acid present, there are several circumstances which 

 make the sulphate more advantageous to use in preparing amido- 

 sulphonic acid than the hydrochloride, and therefore to be preferred to 

 it. In the first place, the sulphate is easy to get in large crystals, on 

 the small scale, and these are practically non-deliquescent, and it is a 

 much eben per salt than the other, when its preparation from sodium 

 nitrite is effectively carried out ; in the second place, sulphuric acid 

 (hydrochloric acid hardly) very greatly reduces the solubility of 

 amidosulphonic acid in water. 



To prepare amidosulphonic acid from hydroxylamine sulphate, 



