122 Scientific Proceedings, Royal Dublin Society. 



II. — Fuming Nitric Acid. 



Ten grams of fuming nitric acid (sp. g. 1-5) were added slowly, with shaking, 

 to half its weight of ethyl-o-tolylurethane, the mixture being kept cold, as the 

 reaction was inclined to become violent. After allowing it to stand for a short 

 time, the reaction subsided, and the liquid was then heated for some hours on the 

 water-bath. Brown fumes were evolved, and the action was allowed to proceed 

 gently, a few c.c. of acid being added from time to time, as the evolution of 

 fumes decreased. In addition to a small amount of oxalic acid, a solid cake was 

 deposited. 



The cake was washed with water, and recrystallised a few times from alcohol. 

 The pure compoi;nd consisted of fine white needles, which melted at 159°-160^C. 

 On analysis the following results were obtained : — 



0'1215 g. of the substance gave 16-7 c.c. of moist nitrogen at 20° 0. and 744 mm., 

 corresponding to N 15-8. 

 CioHi.OelSrs requires N 15-6. 



4.Q-I)inifro-2-vieth'j/l-phenylurefhane is easily soluble in chloroform, hot alcohol, 

 or benzene, somewhat soluble in cold alcohol and ether, and slightly soluble in 

 petroleum ether. 



C— ACTION OF NITRIC ACID ON ETHYL-0-TOLYLUBETHANE IN TEE 



PRESENCE OF SOLVENTS. 



I. — Til Cold Solvents. 



Cardan tetracJiloride. — One, two, three, four, and six molecular proportions of 

 fuming nitric acid (sp. g. 1'5) were added to five solutions, each containing five 

 grams of ethyl-o-tolylurethane in 50 c.c. of carbon tetrachloride. As two layers 

 were formed in each case, the liquids were shaken continuously for a month, at the 

 end of which time they were yellow in colour, the intensity varying with the 

 concentration of the acid. The solution to which six molecular proportions of 

 nitric acid had been added contained a few crystals of oxalic acid. There was no 

 formation of solid in the other bottles, but on allowing the two layers to evaporate 

 separately in each case, crystals melting at 159°-160°C. identical with the 

 substance described in B — II were obtained from the contents of the flasks, to which 

 one, two, three, four, and six molecular proportions of nitric acid had been 

 added respectively. 



In similar experiments in which glacial acetic acid was the solvent the urethane 

 was recovered unchanged. 



II. — In Hot Solvents. 



(a) Glacial acetic acid. — About 10 c.c. of fuming nitric acid (sp. g. 1-5) were 

 added gradually to a solution of ten grams of ethyl-o-tolylurethane in 50 c.c. of 

 glacial acetic acid. An immediate reaction ensued, with evolution of brown fumes, 

 the liquid becoming orange-red in colour. After prolonged heating on the water- 

 bath, with addition of small quantities of the acid from time to time, the liquid 

 was poured into water. The oil obtained was waslied free from acid, and dissolved 

 in alcohol, from which it crystallised in a few days. The crystals melted at 

 X59°-160° C, and were identical with the compound described in B — II. 



