IMIDES OF BEXZEXEDISULPHOXIC ACIDS. 13 



b) Nitrogen. 



0.1373gr. of the crystals gave G.Oc.c. moist nitrogen at 1.3° and 7."')4ra.m. 



Nitrogen found 5.0Aoo 



„ calculated 5.04 „ 



c) Sulphur. 



0.1245 gr. of the crystals gave 0.2075 gr. of barium sulphate. 



Sulphur found 22.90^^ 



calculated 23.01 „ 



p-Benzenedisulphimide. 



This imide was obtained by reducing the oxime by means 

 of sulphur dioxide. The powdered oxime was suspended in 

 aqueous alcohol contained in a flask, sulphur dioxide passed to 

 saturation, and the whole kept at a temperature of about 50°. 

 Complete dissolution did not take place even when the reduction 

 was complete, owing to the slight solubility of the imide in 

 alcohol and consequent precipitation of it as the oxime was dis- 

 solved and reduced. Three or four hours w^ere necessary before 

 complete reduction took ]^lace, which could be ascertained by 

 adding a drop of the reacting mixture into water, when complete 

 disappearance of the turbidity was observed. The small solubility 

 of the imide in water and especially in alcohol made tlie purifica- 

 tion of this substance very easy. The contents of the flask w^ere 

 transfered into a dish and evaporated over a water-bath to a 

 small bulk. The mother liquor was pressed out of the crude 

 crystals of the imide which separated out on cooling, and the 

 latter washed with a small quantity of alcohol.^ Recrystallisation 

 from water yielded the pure product. 



1. From 2.3 gr. of the oxime 1.6 gr. of the crude imide were obtained. 



