134 PROCEEDINGS OF THE AMERICAN ACADEMY. 



trated, when it deposited crystals which melted at 174°-175°, aud 

 were therefore the unaltered tetrabrombenzol. The mother liquor 

 was evaporated to dryness, and cautiously sublimed at as low a tem- 

 perature as possible ; the crude sublimate melted at 42°-43°, and 

 upon resubliming it with the same care its meltinj; point rose to 44°, 

 the melting point of unsymmetrical tribrombenzol (1, 2,4), which 

 must be formed if one of the atoms of bromine is removed from this 

 tetrabrombenzol. Only a small portion of the substance, however, 

 reacts with the sodic ethylate, by far the greater part remaining 

 unaltered. 



Experiment with Symmetrical Tribrombenzol. 



Blau* states that tribrombenzol is converted by sodic methylate into 

 symmetrical dibromphenol, when the substances are heated together in 

 methyl alcohol solution for two to three days at I20°-130°. We 

 accordingly tried an experiment to see whether sodic ethjdate would 

 liave a similar action in open vessels, as we had used this reagent in 

 the preceding work. Ten grams of tribrombenzol were boiled with a 

 solution of the necessary amount of sodic ethylate in about 200 c.c. of 

 alcohol for somewhat more than seventy hours ; the aqueous wash 

 waters from the product gave a good test for sodic bromide, and in 

 addition to a large amount of unaltered tribrombenzol we obtained a 

 very little of an oil, probably the dibromphenol ethylether, which is a 

 liquid. As this result, which it will be observed confirms Blau, had 

 given us all the information about the reaction which we wished, we 

 did not pursue the work further. 



Hexabrombenzol gave when boiled with sodic ethylate a good test 

 for sodic bromide. The organic product was an oil, and a great deal 

 of unaltered hexabrombenzol was recovered. Hexachlorbenzol gave 

 a similar result. 



Action of Sodic Ethylate on Tetrabromdinitrobenzol. 



In the experiments described in this paper the fourth atom of bro- 

 mine was removed from tetrabrombenzol by sodic ethylate, while in 

 the work by W. D. Bancroft and one of us f upon the tetrabi-om- 

 dinitrobenzol, this fourth atom of bromine was not removed by 

 aniline or sodium malonic ester. It seemed of interest therefore to 

 try the tetrabromdinitrobenzol with sodic ethylate, and see whether it 

 behaved like the tetrabrombenzol with this reagent or in the same way 



* Monatsh. f. Chem., VII. 630. t These Proceedings, XXIV. 288. 



