152 Scientific Proceedings, Royal Dublin Society. 



more nitrous fumes having been passed in once during the week. The solution 

 was at first green, and became brown on standing. A yellow solid also separated. 



The yellow solid was separated from the liquid, and when crystallised from 

 acetic acid or acetone it gave slightly yellow-coloured leaves, melting at 205"-206^C. 



An analysis of this compound gave the following result : — 



0'1045 g. of the substance gave 15 c.c. of moist nitrogen at 18-5" C. and 762 mm., 

 corresponding to "N" 16'67. 

 CoHioOiNj required N 16-55. 



The compound was therefore a trinitro-triphenylurea. 



It is a slightly coloured substance, fairly soluble in alcohol, acetone, and acetic 

 acid ; slightly soluble in ether, chloroform, and carbon tetrachloride. 



A further quantity of this substance was obtained from the acetic acid solution. 



B.— ACTION OF NITROGEN PEROXIDE ON TRIPHENYLVREA. 



5 g. of triphenylurea were dissolved in 100 g. of glacial acetic acid, and nitrogen 

 peroxide passed into saturation at room temperature. The mixture was allowed to 

 stand for a week at room temperature, more nitrogen peroxide having been passed in 

 during the week. The solution, which was at first yellow, became deep brown, and 

 a yellow solid separated. 



The solution was filtered from the solid, which was found to be identical with 

 the trinitro-triphenylurea described above. Prom the solution, by precipitation 

 with water, a further quantity of this substance was obtained. 



G.— ACTION OF NITRIC ACID ON TRIPHENYLUREA. 



I. — In the Presence of Solvents. 



(a) Glacial acetic acid. — Triphenylurea (5 gr.) was dissolved in 100 g. of glacial 

 acetic acid, and treated in the cold with one, three, six, and nine molecular amounts 

 of acetic acid. The mixtures were allowed to remain at room temperature for two 

 months. 



(1) The solutions in the bottles with one and three molecular amounts of 

 nitric acid developed a purple colouration, but all the triphenylurea was recovered 

 unchanged. 



(2) In the bottle to which six molecular amounts of nitric acid had been added 

 a purple colouration was also developed in the solution. This after some time 

 changed to deep brown. Towards the end of the two months a yellow substance 

 began to separate. 



The solution was filtered from the small amount of solid. The latter was 

 found to consist of two substances, one easily soluble and the other difficultly 

 soluble in acetic acid. The difficultly soluble substance crystallised from glacial 

 acetic acid in leaves melting at 205°-206" C. It was identical with the trinitro- 

 triphenylurea obtained previously, as the addition of the latter substance to it 

 did not affect the melting point. The more easily soluble substance was soluble 

 in alcohol, acetone, and glacial acetic acid, from which it crystallised as yellow 

 prisms, melting at 190°-191° C. (uncorr.). This substance, as was afterwards 

 found, was a dinitro-triplienylurea. 



From the original acetic acid filtrate some of the unchanged urea was obtained, 

 together with further quantities of the dinitro-triphenylurea. 



