168 Proceedings of the Royal Irish Academy. 



by mixing the substance witli an equal quantity of Ji^-nitro-phenylurethane. 

 The carbon tetrachloride was neutralised with barium carbonate, filtered, and 

 distilled. The residue which solidified on standing consisted of slightly 

 impure ^-nitro-phenylurdhane, which was recovered in a pure condition by 

 recrystallising it from carbon tetrachloride. 



4. Even in carbon tetrachloride solution, the nitration of the urethane by 

 the nitrous acid proceeded slowly, the mixture after fourteen days containing 

 unchanged phenyhcrethane in addition to some ^-nitro-plmrylureihane from 

 which it was separated by means of petroleum ether. 



(6) Nitrous fuvies. — 1. Nitrous fumes, obtained by the action of nitric 

 acid on arsenious oxide, and dried by means of calcium chloride, were passed 

 into a solution of 2 grams of phenylurethane in 20 grams of glacial acetic acid 

 for about forty minutes. The dark green solution was poured into water, and 

 the green oil which separated was dissolved in ether, its colour changing to 

 deep red. The ether was evaporated in a vacuum, and the reddish oily 

 crystals which remained were boiled with alcohol and animal charcoal. From 

 the hot liquid pinkish acicular crystals, melting at 126°-I30^ C, sepai-ated on 

 cooling. These, after recrystallisation, melted at 130°-131° C, and were 

 found to be 4--nit'ro-pJienyh(,rethane. 



In another experiment in which the nitrons fumes were passed through 

 the solution for only twenty minutes, the mixture, which had a deep red 

 colour, gave, when poured into water, a yellow oil, which solidified, forming 

 pale yellow crystals. The latter after recrystallisation from i^etroleum ether 

 were identified as phenylurethane. 



2. A five per cent, solution of phenylurethane in glacial acetic acid vs'as 

 cooled in a freezing mixture (the acetic acid solidifyingl, and then treated with 

 nitrous fumes for fifteen minutes. The mixture when poured into water agaiu 

 gave a readily solidifying oil, which proved to be phenylurethane. 



o. A solution of 1 gram of phenylurethane in 10 grams of carbon tetra- 

 chloride was cooled in ice and salt," and a current of nitrous fumes was passed 

 through it for twenty minutes. The solution became green in colour, and a 

 yellow oil separated from it. The oil solidified on standing, and after recrys- 

 tallisation from carbon tetrachloride was found to be U-n%tro-]>henylurethane. 



In similar experiments in which ether, at the ordinary temperature and 

 below 0° C, was employed as the solvent 4-nitro-phenylurethane was also got. 

 The same product was found when dry nitrous fumes were passed into an ice- 

 cold solution of 5 grams of phenyhu-ethane in 250 c.cs. of petroleum ether. 



II. Ethyl-phenylurethane. 



Five per cent, solutions of ethyl-phenylurethane in glacial acetic acid, 



