Q2 DIVERS AND HAGA. 



Potassium imidosulp horiates. 



THpotasskim imidosîilpho7iate. — This yjilt was obtained by Fremy 

 by tlie hydrolysis of potassium nitri]osul})honate, and this by the 

 action of sulphite upon nitrite. Claus and Raschig have both ])ub- 

 lished accounts of the preparation of the salt in this way. it has 

 also been obtained by double decomposition between diammonium 

 imidosulphonate and a potassium salt (Fremy, Bergiund): also from 

 the dia,mmomum s;ilt by Woronin, by converting this first into 

 Jacquelain's barium salt and then decomposing that with potassium 

 sulphate. 



Imidosulphonates are derived fr<^m nitrilosul])honates by hy- 

 drolysis readily enough, but as the two potassimn salts are but 

 sparingly soluble in water, and the imide salt almost as i-en.dily passes 

 into the amide salt l)y further hydrolysis, the pre))aration of dipotas- 

 siiun imidosulphonate as hitherto carried out has ] »roved of uncertain 

 productiveness. On the other hand, the conversion of sodium nitrilo- 

 sulphonate into disodium imidosulphonate can he very easily ;ind 

 exactly effected, and, since the disodium imidosulphonate is very 

 soluble, the insoluble ])otassium salt can be prepared from it by double 

 decomposition and ])recipitation withc^ut any trouble. Tlius ])re]>ared 

 it is also verv pure ;ind, consequently, sttible. It can also be i-ecovered 

 from mercuric dipotassium imidosulphonate by the action of nitric 

 acid (p. 96) 



Dipotassium imidosulphonate results also from the action of heat 

 upon ])otassium amidosulph<mate. The first knc^wledge of this in- 

 teresting chîinge— :^H.,NS()Jv=H3N + HN(S0,K),— is due to IJerg- 

 lund. We ourselves find that at oi- just beloAv 350° this change 

 proceeds readily and productively, the gas evolved being nmmonin 

 unmixed with any nitrogen. At this temperature the salt, in our 



