282 PROCEEDINGS OF THE AMERICAN ACADEMY 



consisted only in tlie formation of the ketone. This result is the more 

 remarkable because Ileckmann * obtained from the orthoparadinitro- 

 phenylacetacetic ester by treatment with sulphuric acid of about 10 

 2)er cent exclusively the dinitrophenylacetic acid without a trace of the 

 corresponding ketone. As the presence of bromine in our compound 

 could hai'dly have caused such a great difference in the action of the 

 sulphuric acid, we infer that it must have been caused by the difference 

 iu strength of the sulphuric acid, Heckmann's containing about 10 per 

 cent of HaSO^, while ours contained 54 per cent. This inference will 

 be tested by experiment in the coming year. 



Properties. — The bromdinitrobeuzylmethylketone crystallizes from 

 hot alcohol by cooling in white rectangular plates, often with a right- 

 angled notch in one corner, sometimes also in plates with parallel sides 

 and a deep notch in each end, which makes them look like reels. If 

 crystallized by the evaporation of its alcoholic solution, it forms cylin- 

 drical tufts of needles looking like spires of moss, or much branched 

 forms resembling certain seaweeds. Both the plates and the branch- 

 ing needles commonly occur together. It melts at 112°-113° and is 

 essentially insoluble in ligroine ; nearly insoluble in cold water, more 

 soluble in hot, but still very sparingly ; slightly soluble in ether, car- 

 bonic disulphide, benzol, or methyl alcohol, its solubility in the last two 

 solvents is increased by heat ; tolerably soluble in ethyl alcohol in the 

 cold, freely when hot ; ethyl alcohol dissolves it more freely than methyl 

 alcohol ; tolerably soluble in glacial acetic acid ; soluble in chloroform ; 

 and freely soluble in acetone. Hot alcohol is the best solvent for it. 

 Strong sulphuric acid has no action on it in the cold, but when warmed 

 dissolves it, forming a colorless solution from which water precipitates 

 the ketone essentially unaltered, although it appears at first in spheri- 

 cal groups of thickly set radiating needles, a form in which it is also 

 obtained sometimes when prepared by the action of sulphuric acid on 

 bromdinitrophenylacetacetic ester, but these crystals are converted by 

 crystallization from alcohol into the rectangular plates described above. 

 Strong nitric acid acts like strong sulphuric acid. 



The bromdinitrobenzylmethylketone has well marked acid proper- 

 ties, and in this respect fiir surpasses the desoxybenzoine from which 

 according to Victor Meyer f no sodium compound could be isolated. 

 In alcoholic solution the ketone gives a dark purplish red color with 

 sodic hydrate or ethylate. Aqueous ammonic hydrate gives only a 

 slight red color with it, which is increased by warming for a short 



* Ann. Chem., ccxx 134. t Ber. d. ch. G. 1888, p. 1291. 



