1 14 Scientific Proceedings, Royal Dublin Society. 



At low temperatures and concentrations, in acetic acid solution, apparently no 

 reaction occurred between the acid and the urethane, even on prolonged standing. In 

 carbon tetrachloride solution, however, the acid and the urethane reacted with 

 difficulty. When the amount of the acid was equivalent to three molecular pro- 

 portions and the mixture was allowed to remain at the room temperature for six 

 weeks, 4-nitro-diphenylurethane was formed, while with four and with six molecular 

 amounts of the acid the main products were 4"10- and 2 10-dinitro-diplienylui'- 

 ethanes. On the other hand, nitrogen peroxide, in carbon tetrachloride solution, 

 converted it more readily into an oily mixture, from which, by decomposition with 

 alcoholic potash, 4 10- and 2-10-dinitro-diphenylamines were obtained. 



Experimental. 

 K.— ACTION OF NITRIC ACID ON DIPHENYLURETHANE. 



I. — Action of Cold Concentrated Nitric Acid. 



Five grams of diphenylurethane were added slowly to seven and a half cubic 

 centimetres of nitric acid (sp. g. 1'42), which was kept well cooled during the 

 addition of the urethane. The mixture was allowed to remain for five days in a 

 stoppered bottle at the temperature of ,the laboratory. During this time a dark- 

 coloured oil separated. The contents of the flask were poured into a considerable 

 excess of water, and the aqueous layer was decanted from the underlying heavy 

 brown oil. The latter was dissolved in warm alcohol, from which a yellowish-white 

 solid separated on cooling. The solid was removed by filtration. It crystallised 

 from alcohol in clusters of colourless prismatic crystals, which melted at 68" C. 

 A mixture of this solid with the original urethane, which melted at "72" C, melted 

 at about 35' C. 



It gave on analysis the following results : — 



0'2051 g. of the substance gave 17"8 c.c. of moist nitrogen at 17"8° C. and 768 mm., 



corresponding to N lO'U. 

 CigHiP^N, requires N 9-8. 



A small quantity of the solid was heated with alcoholic potash for a few hours 

 on a water- bath ; the solution was diluted with water, and the solid which separated 

 was filtered off. Wheu the solid was crystallised from a mixture of chloroform 

 and alcohol, yellow leafy crystals melting at 133"-134°<J. were obtained. These 

 crystals gave a violet coloration with a mixture of concentrated sulphuric acid 

 and a trace of sodium nitrite, and their melting point was not att'eeted by 

 addition to them of 4-nitro-diphenylamine, with whicli the substance was identical. 

 It follows, therefore, that the mononitro compound, melting at 68° C, must be 

 4-nitro-diphenylurethane. 



4:-ISIitro-diphenylurethane consists of colourless prisms which are sparingly soluble 

 in petroleum ether, and very soluble in ether, alcohol, chloroform, benzene, or 

 acetone. 



\1.— Action of Cold Fuming Nitric Acid. 



Five grams of diphenylurethane were added slowly, with frequent shaking of 

 the mixture, to ten cubic centimetres of fuming nitric acid. The dark-coloured 

 solution was allowed to remain at the laboratory temperature for two days, and 

 was then diluted with several times its volume of cold water. The flocculent 

 precipitate wliich separated was washed with water, and dissolved in hot alcohol, 

 from which a yellow solid and a brown oil separated on cooling. 



