IMIDES OF liENZENEDISULrHONIC ACIDS. 15 



IV. Oximes and Imides of o-Benzenedisulphonic Acid. 



The difficulty of procuring the materials was strongly felt 

 in the investigation of the oxime and the imide of o-benzenedi- 

 sulphonic acid. The starting point was p-bromauiline-o-sulphonic 

 acid, and this was transformed into p-brom-o-benzenedisulphonic 

 acid according to the method of Armstrong and Nappée, (Chem. 

 News, 82, 46 ; 1900). Only two grammes of p-brom-o-benzene- 

 disulphochloride was at my disposal, from which I had to prepare 

 the oxime and also the imide. 



A small quantity of potassium p-brom-o-benzenedisulphouate 

 was debrominated with zinc dust and caustic potash, and from 

 the product o-benzenedisulphochloride was prepared. But the 

 quantity under manipulation was less than one gramme. 



From these sulj^hochlorides the corresponding oximes and 

 imides were prej)ared according to the methods already described 

 but owing to the small quantity of the materials it was difficult 

 to make many analyses. 



The oxime of p-hrom-o-benzencdisulphonic acid is tolerably 

 soluble in acetone and alcohol, and crystallises from the former 

 solvent in well defined prisms. Sulphur was estimated in the 

 sample dried at 100°-150°, w^ith the following result : 



0.1374 gr. gave 0.2076 gr. of barium sulphate. 



Sulphur found 20.75 1^^ 



Calculated for HON : (SO,), CgH, Br 20.38 „ 



In order to see whether this ortho-compound has the cyclic 

 monomolecular constitution or not, its molecular weight was deter- 

 mined by observing the elevation of the boiling point of acetone. 

 The result agreed exactly with the monomolecular formula. 



