( 300 ) 
dinitroderivative m. p. 95° starts immediately, evidently owing to the 
catalytic action of the nitrous acid, and on addition of sodium carbon¬ 
ate to the filtrate the red product m. p. 76° is obtained *). p. Nitro- 
diethylaniline is also readily converted into the 1.2.4-dinitroderivative. 
We may, therefore, conclude that even when we use pure sulphuric 
acid and colourless nitric acid, traces of nitrous acid are formed in 
the nitration of diethylaniline, which accelerate the further nitration 
in the aqueous solution, (after pouring into iced water) particularly 
if the liquid has not become too diluted. 
A judicious choice of the acid-concentration in the liquid obtained, 
after pouring the nitration mixture into water, might render it 
possible not to obtain the compound of 1.2.4- and 1.3.4-dinitrodi- 
ethylaniline (m. p. 59°), but these components separately, because, 
as we have noticed, the 1.2.4-compound, m. p. 80°, has somewhat 
stronger basic properties than the 1.3.4-compound. 
A series of experiments now demonstrated that both conditions 
may be fulfilled, while it was shown also that within definite limits, 
a quantity of nitric acid larger than that calculated for 2 mols. has 
a favourable influence. 
The following modus operandi can now be recommended when 
large quantities of those new dinitroderivatives have to be procured 
100 grams of diethylaniline are dissolved in sulphuric acid (D. j .84) 
up to 1200 c.c. Of this solution are taken portions of 120 c.c., and 
after cooling to 0° a solution of 14 grams of nitric acid, (D. 1.49), 
in 42 grams of sulphuric acid is added, care being taken that the 
rise of temperature during the nitration does not exceed 5°. After 
the mixture has been standing for a few hours it is poured with 
thorough stirring into a mixture of 250 grams of water and 250 
grams of ice. The final temperature is then about 30°. 
The solution often clear at first soon becomes turbid and deposits the 
product in. p. 95°. After about an hour the liquid is filtered, and 
if the filtrate no longer gets turbid to any extent an equal volume 
of water is added whilst stirring. A yellow product is precipitated 
which is also collected; this is the 1.2^4-dinitrodiethylaniline melting 
at 80°, which is sometimes contaminated with a little red 1.3.6- 
dinitrodiethylaniline, particularly if more water has been used. 
l ) If we dissolve m. nitrodiethylaniline in dilute nitric acid (D 1.22) we obtain, 
®J? er a lon S time > besides the products melting at 95° and 76°, also a dinitromono- 
ethylamline 1.3.6, which is also formed in the oxidation of the product m. p- 76 
with chromic acid in acetic acid solution. 
