565 
whieh did not differ double the refractive effect calculated by 
Brünr for the CH, group viz. 9.2, but only 7.8. 
In order to indicate the difference between those pseudo-homolo- 
gues Hanrzsca avails himself of subsidiary valencies. 
As Hantzscn stated he had obtained the 3.4. dinitro-dimethyl- 
aniline by the action of nitric acid (D. 1,3) on dimethylauiline, 
v. RompurGH') supposed that for his experiments he did not use this 
substance, but 2.4. dinitro-mono-methyl-aniline. This supposition 
proved to be true, as indeed in the above mentioned reaction this 
substance was formed. 
In connection with this mistake it appeared to me of some 
interest to test the theory of Hanrzscn, built by him on the investi- 
gation of these two and five more substances, to a far more 
extensive material. At the same time I wish to combine with 
this research an investigation concerning the nitration of dimethyl- 
and diethyl-p-toluidine, because in doing this 1 expected to obtain 
different substances, which with a great number of comformable 
nitroanilines, kindly put to my disposition by Prof. v. RoMBUrGH, 
I might subject to a comparative refractometric research. 
Nitro-deriwatives of -dimethyl-p-toludine. 
I prepared dimethyl-p-toluidine according to the method of SrApEL ’*). 
After having converted this, by nitration in cone. sulfuric acid, 
into 2. nitro-dimethyl-p-toluidine, I tried to nitrate this last substance | 
further with diluted nitric acid. 
To this end, I dissolved 3 grams of this product in 40 c.c. of 
nitric ‘acid (D. 1,20) and added some sodium nitrite. Soon a pale 
yellow substance precipitated, showing the composition of a dinitro- 
tolyl-methyl-nitrosamine, which however proved to be a mixture of 
2.3- and 2.5-dinitro-tolyl-methyl-nitrosamine. To prevent the forma- 
tion of nitrosamines | decided to add urea. 
7.5 Grams of 2 nitro-dimethyl-p-toluidine were added in little 
portions to 150 ¢.c. of nitric acid (D. 1,20) in which 0.5 gram of 
urea had been dissolved. Next day, the brownish-red liquid, which 
did not deposit a precipitate, is cautiously mixed with water. When 
about 150 ¢.c. had been added, an orange-brown substance began 
to separate slowly. This having been deposited, water was slowly 
1) Proc. Roy. Akad. Amst. Jan. 28, 1911. 
2) B. 16, 29 (1883). If HBr-p-toluidine is heated with a surplus of methyl 
alcohol, then is produced as a bye-product the trimethyl-p-tolylammoniumbromide, 
beautiful colourless crystals, which decompose at about 225°, . 
