RvAN & O'ToOLE — Action of Oxides, ^-c.^ on the Phenytureas. 149 



as-Diphenylurea reacted readily with nitrous fumes and nitrogen peroxide in 

 acetic acid solution with evolution of a gas. It yielded in each case a yellow 

 compound, which melted with decomposition about 146° C. Boiled with acetic 

 acid it yielded a red substance, from which 4'4'-dinitro-diphenylamine was 

 separated. The original substance was probably, therefore, 4-4'-dinitro-diphenyl- 

 nitrosamine, mixed with some of its isomers. 



4'4'-Dinitro-diphenyl-nitrosamine has been described by P. Juillard [Bull. Soc. 

 Chim. Paris (3), xxxii (190r)), pp. 1172-1190], He obtained it as orange yellow 

 needles, melting with decomposition at 150° C. 



J. L. F. Eeudler (loc. cit.) nitrated as-diphenylurea with ten molecular parts of 

 99"7 per cent, nitric acid, and obtained a reaction product from which no pure 

 substance was isolated. It gave no nitramine reactions, neither did it yield a gas 

 when boiled with water. It contained, therefore, no nitramine group. By using 

 a smaller excess of nitric acid he obtained 4-4'-dinitro-as-diphenylurea. At a some- 

 what elevated temperature and with much nitric acid in the presence of sulphuric 

 acid he obtained 2-4'-2'-4'-tetranitro-as-diphenylurea, and probably 2-4-6'2'-4'-6'- 

 hexanitro-diphenylamine. 



By the action of nitric acid (sp. gr. 1'51) on this urea in the cold we obtained 

 2"4"2'"4'-tetranitro-diphenylamine. 



as-Diphenyhu'ea in acetic acid at low concentrations was not nitrated by one, 

 two, four, or six molecular parts of nitric acid in the cold. Yellow colourations were, 

 however, developed in all cases. It did not nitrate in carbon tetrachloride 

 suspension with one or two molecular parts of nitric acid, but with four and six 

 parts of acid it gave a yellow substance, from which no pure compound was separated. 



In the cold, nitrous acid (up to six molecular parts) was without action on as- 

 diphenylurea in glacial acetic acid solution. 



A.— PREPARATION OF AS-DIPHENYLUREA. 



(a) 5 g. of diphenylurea chloride were shaken with 100 c.c. of methylated 

 spirit containing 1-4 g. of ammonia (four molecular parts to one of the chloride). 

 The mixture was allowed to remain at the temperature of the room for twenty- 

 four hours. The undissolved diphenylurea chloride had then gone into solution, 

 and its place was taken by large prismatic needles, which, on washing with water, 

 melted at 189° C. The substance was as-diphenylurea. 



(&) It was more expeditious, however, to obtain the urea by allowing the 

 reaction to take place at the temperature of boiling spirit. 



25 g. of diphenylurea chloride were heated to boiling with 100 c.c. of 

 methylated spirit, and a stream of ammonia was passed into the mixture for a 

 quarter of an hour. The undissolved diphenylurea chloride went into solution, 

 and long colourless needles of as-diphenylurea separated. On allowing the 

 mixture to cool a further quantity of the urea separated. The solution was 

 filtered from the separated solid. This, when well washed with water to remove 

 ammonium chloride, melted at 189° 0. Eecrystallisation from alcohol did not 

 raise the melting point. The as-diphenylurea obtained was therefore pure. By 

 evaporating the spirit solution down to small bulk a further quantity of substance 

 was obtained, which, when washed with water, left the as-diphenylurea. 



The yield was theoretical. 



V,.— ACTION OF NITROUS FUMES ON AS-DIPHENYLUREA. 



as-Diphenylurea (5g.) was dissolved in 100 g. of glacial acetic acid, and nitrous 

 fumes were passed in at room temperature. The solution became red, then green, 

 with the evolution of a gas throughout the liquid. On allowing to remain at room 



