130 Scientific Proceedings, Royal Dublin Society. 



The benzene solution was washed with water and the benzene distilled ; the 

 residue was washed with water and recrystallised from alcohol, from which 

 it separated in the form of sulphur-yellow prisms, which melted at 56°-58° C. 

 A mixture of it with the nitro compound, melting at 55"-56" C, formed by the 

 action of nitrogen peroxide or nitric acid on ethyl-phenylurethane, melted about 

 35°-38° C. 



2A-Dinitro-phenyluretlia')u. — Following the method of Hager [Ber. d. Dtsch, 

 Chem. Ges., xxvi (1893), p. 29], 2-nitro-phenylurethane was converted, by dis- 

 solving it in fuming nitric acid and keeping the mixture cool, into 2.4:-dinitro- 

 phenylurethane, which melted at 109°-111° C. 



A mixture of the latter comjiound with the dinitro substance formed by the 

 action of "mixed acid" on 4-nitro-ethyl-phenylurethane melted at 108°-110°O. 

 It is evident, therefore, that, although the mononitro compound was nitrated by 

 nitrogen peroxide or nitric acid in the cold to 2.4-dinitro-ethyl-phenylurethane 

 without the separation of the ethyl radical, the latter radical was separated 

 during the further nitration of the mononitro body by means of " mixed acid." 

 Tills view was further substantiated by the conversion of the two dinitro com- 

 pounds, which were obviously identical, into the same trinitro derivative, which 

 melted at 144°-146" C. 



Hager's statement {loc. cit.) that the dinitro-phenylurethane can be obtained 

 by nitrating either o. or p. nitro-phenylurethane, and must therefore be 2.4-dinitro- 

 phenylurethane, was confirmed. 



4-Nitro-phenyhirethane, which was obtained by heating a benzene solution of 

 p.-nitraniline and chloroformic ester under a reflux condenser for three hours, 

 after recrystallisation from alcohol melted at 132° 0. It was converted by treat- 

 men t with fuming nitric acid into the same dinitro-phenylurethane as was obtained 

 by the action of nitric acid on 2-nitro-phenylurethane. 



Summary. 



1. Like other urethanes, ethyl-phenylurethane nitrated with difficulty. Unlike 

 ethyl-o-tolylurethane, it nitrated to derivatives of the tertiary urethane as well as 

 to derivatives of the parent secondary urethane. Tlie former reaction prepon- 

 derated at low, the latter reaction at moderately high, temperatures. 



2. Nitrogen peroxide in carbon tetrachloride solution converted the urethane 

 into its 4-nitro derivative and into another crystalline substance, which was 

 probably 2.4-dinitro-phenyl-ethylurethane. 



3. The same two nitro derivatives were obtained by the action of fuming nitric 

 acid on ethjd-phenylurethane at a low temperature, but. when the temperature 

 was allowed to rise spontaneously during the reaction, the chief products were 

 4-nitro- and 2.4-dinitrophenylurethane. 



4. A mixture of concentrated nitric and sulphuric acids converted ethyl- 

 phenylurethane into 2.4-dinitro- and 2.4.6-trinitro-phenylurethanes. 



5. At low concentrations in acetic acid solution and at the ordinary tempera- 

 ture the urethane was converted very slowly and incompletely by nitric acid into 

 its mononitro and dinitro derivatives. 



In carbon tetrachloride solution tlie substances reacted more easily with 

 formation of 4-nitro-phenyl-ethyI-urethane. 



The above research was undertaken at the request of the Eesearch Section of 

 Nobel's Explosives Company, to whom we are indebted for a grant in aid of the 

 investigation. 



