Ryan and Ryan — Action of Acids on Diphcwjlamine. 199 



The colour of the solution changed relatively rapidly through greenish- 

 yellow and green to dark brownish- red, acquiring the latter tint about the 

 seventeenth day and retaining it until the end of the fourteenth week, when 

 the solution was filtered from the brown resinous solid, which had begun to 

 separate on the fifth day, and which finally weighed about 1 gram. 



The yellow solid, which was precipitated from the acetic acid solution by 

 addition of water, was filtered, washed with alcohol, dried, and boiled a couple 

 of times with carbon tetrachloride. The light brownish-yellow, undissolved 

 solid weighed 2 grams, and when recrystallized from acetone and alcohol 

 melted at 198-200° C, and proved to be 2 , -i-S , 10-tetranitro-di/>Jienylamine. 



The solid which separated in small quantity from the carbon tetrachloride 

 on cooling was impure, melting at 180-190° C, while that got from the filtrate 

 on evaporation was also very small in quantity, and when washed with alcohol 

 and ether melted with decomposition at 1 56-1 59° C, apparently being dinitro* 

 d ijihcnylnitrosa mine . 



5 In this experiment the amount of nitric acid employed was 4 - 2 c.cs 

 (6 viols.). The solution became dark green on the second day and rapidly' 

 changed to a dark brownish-red colour, which it retained until the end of the 

 seventh week, when the solution was filtered from the brown resinous solid 

 which had begun to separate on the second day. The solid, which separated 

 from the acetic acid solution on the addition of excess of water, was filtered, 

 washed with alcohol and chloroform, and recrystallized from xylene. It 

 melted about 1 92° C, and proved to be slightly impure 2'i'S-lO-tetranitro- 

 dijJienylamine. From the alcohol -chloroform washings further fractions were 

 obtained, melting at lower temperatures, and which we were unable to resolve 

 into their pure components. 



6. In another experiment 12 - o grams of diphenylamine were dissolved in 

 a mixture of 26 - li c.cs (6 mols.) of nitric acid, and 250 c.cs of glacial acetic 

 acid. 



The solution rapidly acquired a dark-green colour, and later became dark 

 reddish-brown— a copious separation of a brown solid simultaneously taking 

 place. 



After seven days the mixture was filtered, and the filtrate was diluted 

 with a litre of water. The yellow solid, which separated, was filtered, dried, 

 and washed with chloroform. The portion which remained undissolved was 

 recrystallized from boiling xylene, and proved to be 2'4 8-\0-tetraMitro- 

 diphenylamine. 



On evaporating the chloroform extract, a somewhat oily orange solid was 

 obtained. It was purified a few times by solution in boiling alcohol and 

 washing with ether. The semi-crystalline residue melted at 130-140° C, and 



['2. f>2J 



