Ryan & O'Toole — Action of Oxides, 6fc., on the Phenylureas. 153 



(3) In the bottle to which nine molecular amounts of nitric acid were added 

 a purple colouration was developed in the solution. Later on this changed to a 

 deep brown, with the separation of a yellow substance. At the end of two months 

 a fairly large quantity of this substance had separated. 



As in the previous case, the solid was found to consist of a mixture of two 

 compounds, one easily soluble and the other difficultly soluble in glacial acetic 

 acid. The former was the yellow dinitro-triphenylurea previously obtained, as 

 the addition of this substance to it did not affect its melting point. An analysis 

 of it gave the following result : — 

 0-1308 g. of the substance gave 16'8 c.c. of nitrogen (moist) at 16° C. and 766 mm., 

 corresponding to N 15'02. 

 0,gH,AN4 required N 14'8I. 



The substance was therefore a dinitro-triphenylurea. 



The difficultly soluble substance was identical with the above-mentioned 

 trinitro-triphenylurea. 



From the acetic acid solution a further quantity of these compounds was 

 obtained, as well as some of the unchanged urea. 



(b) Carhon tetrachloride. — Five g. of triphenylurea were suspended in 100 g. of 

 carbon tetrachloride and treated in the cold with one, three, six, and nine molecular 

 parts of nitric acid. The mixtures were allowed to remain at the temperature of 

 the room for six weeks. 



(1) The bottle containing one molecular part of nitric acid gave a yellow solu- 

 tion, with a black oil floating on the surface. The latter was separated from the 

 solution and boiled with ether. A small quantity of a yellow substance remained 

 undissolved. This was soluble in acetone, from which it crystallised as yellow 

 prisms, melting at 190°-191°C. It was dinitro-triphenylurea, as a mixture of it 

 with this substance melted at the same temperature. 'The ethereal extract gave 

 on evaporation a black oil, from which no pure substance was obtained. 



By neutralizing with barium carbonate, filtering, and evaporating the carbon 

 tetrachloride solution yielded a black oil, from which a further small quantity of 

 dinitro-triphenylurea was obtained by boiling with ether. 



(2) The bottle to which three molecular parts of nitric acid had been added 

 contained a yellow solid and a red solution. The solution was filtered from the 

 solid, which, after washing with ether and crystallising from acetic acid, gave 

 yellow leaves melting at 20o°-206° C. It was identical with trinitro-triphenylurea, 

 as a mixture of the two substances melted at the same temperature as the 

 individual substances. 



From the carbon tetrachloride solution, on neutralization, filtration, and 

 evaporation, a black oil was obtained. This, when boiled with ether, left dinitro- 

 triphenylurea. 



The black oil obtained by evaporating the ethereal extract yielded no cry.stalline 

 substance. 



(3) The bottle containing six molecular parts of nitric acid gave a yellow solid 

 and a red solution. By methods similar to those employed in (2) the yellow solid 

 was found to consist luainly of trinitro-triphenylurea, whilst the solution was 

 made to yield dinitro-triphenylurea and a black oil which did not crystallise. 



(4) In the case of the bottle to which nine parts of the acid were added, the 

 temperature rose somewhat during the addition of the acid. It yielded a yellow 

 solution, with a black tarry mass in suspension. By boiling the latter with glacial 

 acetic acid a yellow crystalline substance remained undissolved. This was well 

 washed with glacial acetic acid. When heated it began to decompose about 180° C. 



