SULPHAMIDE FROM AMMONIUM AMIDOSULPHITE. O 



of the apparatus, the gases, and the ether are all to be dried 

 before use. 



When as much amidosulphite has been formed as may be 

 wanted or be convenient to prepare, the cooling mixture in the 

 bath is replaced by water, and a slow stream of dry hydrogen 

 passed through the flask, whilst the temperature of the water is 

 slowly raised to about 70° and then kept at that point for five 

 or six hours, or so long as ammonia continues to come off in 

 any quantity. During this operation, the ether, if used, also 

 evaporates. The sulphamide is all formed at temperatures not 

 higher than 30°-35°, and a higher temperature is here employed 

 only for the purpose of destroying as much as possible of the 

 thionic compounds which are formed along with the sulphamide 

 and would, at a later stage, consume much silver nitrate and 

 undesirably produce much ammonium nitrate, if present. The 

 employment of a higher temperature than 70°, to destroy all the 

 thionic compounds, is not possible, because then the sulphamide 

 itself would be decomposed. 



When the flask has cooled down, enough ice-cold water is 

 poured in to dissolve all its contents other than a considerable 

 quantity of sulphur, left by the destroyed compounds. To the 

 yellow, unfiltered solution, which has been poured into an open 

 vessel, barium hydroxide is added in quantity a little more than 

 sufficient for the salts it precipitates, among which are sulphate, 

 imidosulphite, and thiosulphate. In order to lessen the dilution 

 of the solution of sulphamide, the barium hydroxide is used in 

 mixed solution and crystals, as obtained by rapidly cooling a hot, 

 concentrated solution. The precipitate is to be filtered off, though 

 it is not very easy to get a bright filtrate, and, even when this 

 is accomplished, the filtrate soon becomes turbid again, owing to 



