Mr. Buckton and Dr, Hofmann on the Conjugate Sulpho-acids. 379 



Phenyle-Series. 



Action of Sulphtiric Acid upon Benzonitrile. 



From the results obtained in the study of the methjle-, ethyle-, and 

 propyle-series, we may fairly infer that all the homologues of other 

 groups will exhibit a similar deportment. 



It appeared, however, desirable to extend our researches to a class 

 of bodies which are analogous (not homologous) to the preceding 

 series. 



Sulphuric acid appears to act with much less energy upon benzo- 

 nitrile or cyanide of phenyle than upon the foregoing nitriles. No evo- 

 lution of gas is observed until the mixture of the two substances is 

 strongly heated, and then so much sulphurous acid is formed from 

 charring of the cyanide that its presence is almost entirely masked. 



The digestion was continued for two hours, after which the dark 

 residue was treated in the usual manner for the soluble barium-salts. 

 That first obtained consisted of sulphobenzoate of barium. For 

 identification, both the neutral and acid compounds were prepared, 

 the respective formulae of which, 



Ci4 (H4 Baa) ^2 Oio> 

 and 



CiJH5Ba)S2 0io, 

 were corroborated by analysis. 



An examination of the mother-liquor proved, as we had antici- 

 pated, the presence of a more soluble salt. By rapid evaporation it 

 appears as an amorphous mass, but a drop allowed to dry sponta- 

 neously on the stage plate of the microscope exhibits it in the form 

 of minute shuttle-shaped crystals. 



The formula of this body, deduced from a sulphur- and barium- 

 determination, is 



Ci2(H4Ba2)S4 0i2, 



which characterizes it as disulphobenzolate of barium. 



The question naturally suggested itself, whether the same acid 

 could not be prepared directly from the hydrocarbon benzole. 



Mitscherlich has already described an acid (the sulphobenzolic) 

 in which one equivalent of that hydrocarbon is associated with one 

 equivalent of bibasic sulphuric acid. We have proved by experiment 

 that sulphobenzolic acid takes up the elements of an additional equi- 

 valent when it is submitted to the prolonged action of Nordhausen 

 sulphuric acid, and that, in fact, the union of these two bodies pre- 

 sents the most ready method of procuring disulphobenzolic acid in a 

 state of purity. 



The preceding researches establish in two different groups of 

 bodies the existence of a series of bibasic acids containing four equi- 

 valents of sulphur, and which, irrespectively of any special view re- 

 garding their molecular arrangement, may be represented as formed 

 by the association of the hydrocarbon (corresponding to marsh-gas) 

 of the various groups with four equivalents of anhydrous sulphuric 

 acid, — 



