THE TMIDES OF THE AROMATIC SULPHOXIC ACIDS. Ô 



calculations were based not upon the quantity of the oxirae taken, 

 but upon the quantity of the imide actually found. This defi- 

 ciency of free sulphuric acid was probably, to a large extent, due 

 to the formation of ethylsulphuric acid, for, as already shown, 

 when water alone was used as the medium of the reaction, much 

 larger quantities of sulphuric acid were found to be formed. 

 Moreover, in the experiments, in which alcohol was used as the 

 medium, it was found that heating the liquid with hydrochloric 

 acid to löO°C. after the removal of dibenzenesulphimide as its 

 mercury derivative, produced a further quantity of free sulphuric 

 acid. The total sulphur precipitable by barium chloride was then 

 found to make up 91 per cent of the theoretical quantity required 

 by the equation already given (p. 2), the quantity of the sulphate 

 sulphur being calculated with reference to the quantity of diben- 

 zenesulphimide actually found, and not with reference to that of 

 the oxime taken. 



There is thus still a deficiency in the amount of the total 

 sulphates, and this fact shows that dibenzenesulphimide must be 

 partly formed in some other way, unaccompanied by the formation 

 of sulphuric acid. Examination of an alcoholic solution of di- 

 benzenesulphohydroxylamine has shown that hydrolysis of this 

 compound occurs in the solution and that this constitutes a 

 source of dibenzenesulphimide. 



Evidences of the Formation of Ethylsulphuric Acid : — As 

 was shown in the preceding section, the principal product of the 

 action of sulphur dioxide upon an alcoholic solution of dibenzene- 

 sulphohydroxylamine is dibenzenesulphimide. This is produced 

 almost quantitatively, when sulphur dioxide is used in great excess 

 and contact of the solution with the atmosphere is avoided (p. 4). 

 By special experiments made for the purposa (p. 12), it was also 



