(397 ) 
From the erystals were obtained 31 grams, from the motherliquor 10.2 grams, 
total 41.2 grams, 42.8 grams having been started with. 
Solidifying point of the acetocompound from the crystals 109.°15. Therefore pure. 
= a a 5 „ motherliquor 107. 15, corresponding 
with 3.6%, of p-toluidine or 0.37 gram. The sample therefore contained 
0.37 X 100 
HQ = 0.9 0%, impurity. 
Il. 42.8 grams of toluidine converted as before into oxalate. From the crystals 
are taken 30.5 grams, from the motherliquor 11.2 grams, total 417 grams. 
Solidifying point of the acetocompound from the crystals 108.°45 so this still 
contained 1. °/, or 0.34 gram of byproduct. After having been converted once 
more into oxalate, the newly prepared acetocompound now solidified at 109.°15. 
Solidifying point of the acetocompound from the motherliquor 101.°9 corresponding 
with 12.1%) or 1.36 gram. Total impurity present, therefore, 1.36 + 0.34 = 1.70 
corresponding with 4.1 9/,. 
Assuming the impurity to be either aniline or p-toluidine the 
following plan was followed to ascertain which of these two was 
present. Of a mixture of acetanilide (6 grams.) and acetoorthoto- 
luidide (4 grams) the eutectic point was determined. For this was 
found 64.°6 and 65.°1, mean 64.°8,. On adding to this mixture 0.1 
gram of p-acetotoluidide, the said point was found to be 63.°1 and 
63.°6, mean 63.°3,; the latter, therefore, seemed rather sensitive to 
small additions of para. 
5.64 grams of acetanilide were now mixed with 4.36 grams 
of the acetocompound prepared from the motherliquor (1) which, 
according the above examination, contain 4.20 gram of acetoorthoto- 
luidide and 0.16 gram of an impurity, which might be p-acetotoluidide. 
The point of initial solidification of this mixture was found to be 
72.0 and 71°9, the point of complete solidification 62.°6 and 62.°8. 
A mixtute prepared from 5.64 gram of acetanilide, 4.20 grams of 
acetoorthotoluidide exhibited these same points at 72.°1 and 62.8, so 
that the impurity seems to be indeed p-acetotoluide; acetanilide is 
out of the question as then the point of complete solidification ought 
to have coincided with the eutectic point of the pure mixture of 
acetanilide and aceto-o-toluidide. 
The above method will no doubt be found applicable in a number 
of other cases as it is based on a general principle. By its means, 
it is possible to ascertain the purity of organic preparations with a 
greater degree of quantitative precision than has been the case up 
to the present, particularly when dealing with liquid substances. 
Mr. F. H. van per Jaan has ably assisted me in the experimental 
part of this research. 
Groningen, Chem. Lab. Univers. November 1904. 
