JACKSON AND CALVERT. — METAPHENYLENE DIAMINE, 151 



time the solid was completely dissolved, and the liquid had taken on a 

 dark brownish red color. After it was cool, the solution was treated 

 at first with sodic carbonate, and finally with sodic hydrate in excess, 

 which precipitated a brown solid. This was filtered out, washed until 

 free from alkali, and purified by crystallization from boiling water con- 

 taining a little alcohol until it showed the constant melting point 135°. 

 In this recrystallization long heating of the solution should be avoided, 

 as this seems to decompose the substance with precipitation of a black 

 compound. The pure substance was dried at 100° and analysed with 

 the following result : — 



0.3872 gram of the substance gave by the method of Carius 0.5473 

 gram of argentic bromide. 



Calculated for Found. 



CcHoBr, (NH2)2 



Bromine 60.15 60.16 



Properties. — The dibromphenylene diamine crystallizes in fine 

 needles which are white, if the substance is perfectly pure, but usually 

 show a brownish color, which is due to an impurity so slight that it 

 has no effect upon the analysis. It melts at 135°, and is easily solu- 

 ble in alcohol whether hot or cold. It is very soluble in acetone ; 

 easily soluble in ether, somewhat less soluble in benzol, or chloro- 

 form, if cold, easily soluble, if hot; slightly soluble in cold carbonic 

 disulphide, soluble when hot ; very slightly soluble in cold ligroine, 

 more soluble when it is hot ; nearly insoluble in cold water, slightly 

 soluble in hot, but it is decomposed, if boiled for some time with 

 water. The best solvent for it is dilute alcohol. It shows a much 

 stronger tendency to form salts than the tribromdiamine, as it dis- 

 solves in either hydrochloric acid or hydrobromic acid, and the solu- 

 tion leaves the salt on spontaneous evaporation ; cold strong sulphuric 

 acid turns it purple, and then dissolves it, but upon standing the sul- 

 phate separates from this solution in glistening white or pinkish plates, 

 which seem to belong to the monoclinic system ; when hot, sulphuric 

 acid decomposes it ; strong nitric acid dissolves it, and then decom- 

 poses it even in the cold forming a brown solution. A cold solution 

 of potassic hydrate has no effect upon it, but, if the mixture is heated, 

 decomposition sets in as shown by the appearance of a black color. 

 We selected for further sturly the chloride and the bromide of the 

 base with the results described below. 



We have also studied the action of tin and hydrochloric acid on the 

 dibromphenylene diamine. For this purpose 3.75 gram of the dibrom- 

 phenylene diamine were warmed with tin, hydrochloric acid, and pla- 



