150 Scientific Proceedings, Royal Dublin Society. 



temperature overnight a light yellow solid separated as needles. After two days 

 the solution was filtered from the solid. The latter, after washing with alcohol, 

 melted with decomposition at 145°-146'' C. An attempt to recrystallise this 

 substance from acetone seemed to decompose it, yielding a red substance melting 

 with decomposition between 145°-162'C. 'J"he original substance gave a violet 

 colouration with alcoholic potash. 



Some of this substance was boiled for an hour with glacial acetic acid, in order 

 to complete the decomposition effected by the acetone, during which time brown 

 fumes were observed in the neck of the flask. This process yielded a red solution, 

 from which, by precipitation with water, a red substance was obtained melting 

 between 138°-155° C. By fractional crystallisation of this substance from acetic 

 acid, a compound was obtained as prisms melting at 213" C. It was 4'4'- 

 dinitro-diphenylaraine, as the addition of the latter substance to it did not affect 

 its melting point. 



The original compound was therefore probably 4'4'-dinitro-diplienyl-nitrosamine 

 (M.P. 150^ C), which is very difficult to obtain pure. This would account for the low 

 melting point of it as obtained above. Further, 4'4'-dinitro-diphenyl-nitrosamine 

 gives, like this compound, a violet colouration with alcoholic jDotash, and yields, on 

 elimination of the nitroso radical by boilings with acetic acid, 4"4'-dinitro-diphenyl- 

 amine. 



No pure substance was obtained from the original acetic acid solution. 



C— ACTION OF NITROGEN PEROXIDE ON AS-DIPHENYLUREA. 



as-Diphenylurea (5 g.) was dissolved in 100 g. of glacial acetic acid and 

 saturated with nitrogen peroxide in the cold. A gas was evolved throughout the 

 solution. After allowing to remain at room temperature for two days a yellow 

 substance separated out. This was identical with the substance obtained by the 

 action of nitrous fumes on the urea, and was therefore 4'4'-dinitro-diphenyl- 

 nitrosamine, mixed probably with some of its isomers. 



No pure substance was obtained from the red glacial acetic acid fibrate. 



D.— ACTION OF NITRIC ACID ON AS-DIPHENYLUREA. 



I. — In the Presence of Solvents. 



(a) Glacial acetic acid. — as-Diphenylurea (5 g.) was dissolved in 100 g. of 

 glacial aceiic acid and treated with one, two, four, and six molecular parts of nitric 

 acid in the cold. On allowing to remain at the temperature of the room for two 

 months, yellow colourations were developed in every case. This colouration persisted 

 in the solids obtained by precipitation with water. Tlie solid so obtained 

 consisted, however, in every case of the unchanged as-diphenylurea. 



(a) Carbon tetrachloride. — One, two, four, and six molecular parts of nitric 

 acid were added to .5 g. of as-diphenylurea suspended in carbon tetrachloride. 

 The mixtures were allowed to remain at room temperature for two months. A 

 yellow solution and a black oil were obtained in every case. In the bottles to 

 which four and six molecular parts of nitric acid had been added a red substance 

 appeared towards the end of the two. months. 



On addition of ether to the bottles with one and two parts of nitric acid the oil 

 was dissolved, with the separation of a white crystalline substance. This was the 

 unchanged urea. By neutralizing with barium carbonate, filtering, and evaporating 

 to dryness the ether-carbon-tetrachloride solution yielded a small quantity of 

 black oil, from which, however, no pure solid was obtained. 



