48 P. T. Austen—Dinitroparadib b l 
fs 
fusing at 159°, snc the gamma, an oil, which I hope will prove 
easy of separat 
It also bine an réxeatfent test of the purity of the alpha-com- 
pound, since the color of the potassium beta-phenylate is so 
vivid, that if the alpha contains the slightest trace of the beta, 
it is shown by the formation of a red tint on boiling it with di- 
lute alcohol and potassium nitrite. By treating the beta-com- 
pound in the same manner, evaporating to dryness and extract- 
ing with hot carbon disulphide, an admixture of the alpha and 
gamma modifications is easily revealed. In this manner, I have 
succeeded in proving that several specimens of what I thought 
to be pure alpha and beta, were not absolutely free from isomers, 
although the fusing points had long since ceased to show any 
appreciable variation. 
inally this method promises a means of obtaining phenols 
by substitution of the halide in those nitro-halides ‘Which on 
treatment with an alkali suffer substitution of the nitro-group.* 
For if a reaction takes place it is only the halide which can be 
affected. 
Preparation.—150 grams of the raw product, obtained by nitri- 
tion of the paradibrombenzol, were treated in a flask with — 
absolute alcohol until all was in solution. The boiling liqui 
was diluted with hot water until the substance began to per- 
manently separate. Alcohol was then added until solution had 
taken place, on which water was again added} the liquid being 
kept boiling all the time. In this manner, by successively 
adding water and alcohol, the volume of the liquid was brought 
up to ; about 11 liters. The object of this excessive dilution 
was to prevent the separation of the liquid into two layers from 
the removal of the water by t ri KNO,. The flask was taken 
off the sand bath, and 100 grms. of KNO, carefully added. It 
was then replaced, and the fiqued allowed to boil violently. 
The formation of the phenol salt took place quickly. In 
about half an hour, during which water was occasionally added 
to replace the loss by PH heat the reaction was comple 
The contents of the flask were poured into a tall beaker holding 
about 11 liters of cold eaten stirred, allowed to settle, and 
washed several times by decantation to remove the potassium 
bromide and unchanged potassium nitrite. The mass was 
Sine ona see and a owed to drain, after which it was 
ny ¢ 
iiikasty red in boilng, water’ an grees fecolbrined with 4 
* As for instance the dinitro-chlorbenzol of Laubenheimer, Ber. d. d. chem. 
Ges., viii, 1929; ix, 768. 
