230 PROCEEDINGS OF THE AMERICAN ACADEMY. 



the corresponding hydrocarbons, so the bromine can be replaced by 

 other radicals, including the nitro group, much more easily in tribrom- 

 resorcine than in tribrombenzol ; while on the other hand the phenol 

 ethers hold their hydrogen or bromine as firmly as the corresponding 

 hydrocarbons. The one exception we have met with to this statement 

 is the action of nitric acid upon dibromresorcine diethylether, in which 

 the bromine is replaced by nitro groups, so that in this case the ether 

 behaves like the free tribromresorcine rather than like the correspond- 

 ing tribrom ether. This exception is the more remarkable, because 

 we have found that toward other reagents, such as sodic ethylate, this 

 dibrom ether shows the same great stability which characterizes the 

 tribromresorcine diethylether. 



As we could not remove the bromine from the tribromresorcine 

 diethylether with sufficient ease, and the free tribromresorcine, although 

 it gave up its bromine easily, gave unmanageable products since the 

 hydroxyl groups took part in the reaction, we undertook the study of 

 the tribromresorcine diacetate, which we hoped might give products 

 that could be purified and analyzed ; but these experiments did not 

 lead to the desired result, as the acetate was converted into tribrom- 

 resorcine by the reagents used, even boiling with water producing this 

 effect to a slight extent, and consequently the products were those 

 already mentioned as obtained from this substance. When treated 

 with fuming nitric acid, the diacetate gives tribromnitroresorcine di- 

 acetate which melts at 161°. 



The sodium salt of tribromresorcine was also studied. This was 

 obtained in white crystals by precipitating an ethereal solution with 

 alcoholic sodic ethylate, and seemed to contain two molecules of alcohol 

 of crystallization. It was remarkable on account of its slight stability, 

 as even in vacuo or in an atmosphere of hydrogen after standing for 

 a short time it suddenly turned black, when there was a considerable 

 evolution of heat and alcohol vapor was given off. The black residue 

 gave up sodic bromide to water, and also a black soluble salt, while a 

 red product was left behind. The black salt on the addition of acid 

 gave a red precipitate similar to the product insoluble in water, but 

 we were unable to bring either of these red amorphous substances into 

 a condition undoubtedly fit for analysis ; and although some analyses 

 led to a very probable formula and reaction for the decomposition we 

 can give no weight to these results, as we have no proof that the 

 samples analyzed were homogeneous. There is no question that these 

 substances are very similar to the products obtained from tribrom- 

 resorcine and sodic ethylate or carbonate. 



