4-NITRO-5-METHYL-2-SULPHOBENZOIC ACID 195 
once came down and was filtered off and washed free from acid. 
It was then redissolved and reprecipitated for further purifi- 
cation. Finally, it was washed, dried, and recrystallized from 
75 per cent alcohol. * It formed a fine cottony mass of soft 
needles with a melting point of 195°. The yield of the anilide 
was .98 gram. The substance was identified in this case not by 
analysis hut by its exact correspondence with the dianilide 
formed under like conditions as a derivative of the unsymmetri- 
cal acid chloride. Mixtures of the two preparations showed the 
same melting point as that of either of the pure specimens. 
List and Stein^® state that there are three*' products formed by 
the action of aniline on the symmetrical chloride, but there was 
no indication of a third body here, and a consideration of the 
yields obtained will show that no very large amount of the 
material is unaccounted for. 
.27 grams of anil is equivalent to .25 grams of acid chloride. 
.98 grams dianilide is equivalent to .71 grams of acid chloride. 
.96 
Amount of acid chloride taken 1,00 
B. From the Unsymmetrical Chloride . — The process of mak- 
ing the derivatives of the unsymmetrical chloride was the same 
as that used in the action upon the symmetrical chloride. The 
unsymnietrical chloride was dissolved in carbon tetrachloride 
and to the hot solution was added aniline in carbon tetrachloride 
so long as the white precipitate^ — which in contradistinction to 
the action of the symmetrical chloride, came down on the first 
addition of aniline — continued to form. Hydrochloric acid vapor 
was evolved copiously, and the aniline hydrochloride apparently 
did not form to any great extent. There was required for the 
completion of the reaction a moderate excess above the two mole- 
cules of aniline to each molecule of the acid chloride. The pre- 
cipitate which was thus formed, on being stirred gathered into 
a gummy mass which hardened as the solution cooled. Only a 
small amount of material was left in the carbon tetrachloride, 
but in order that all the products might be recovered, it was 
evaporated to dryness as before and the whole solid residue 
ground with hydrochloric acid in a mortar and then allowed to 
stand to remove soluble products. After some hours it was 
filtered and washed with a considerable amount of water. The 
washings were saved with the original filtrates. The precipi- 
i«Loc. cit. 
