JACKSON AND CALVERT. — METAPHEXYLENE DIAMINE. 139 



was furnished bj experiments on the reduction of tribromaniline which 

 was converted into dibromaniline by the action of tin and hydrochloric 

 acid for a few hours. From the facts at present known we are unable 

 to deduce any rule in regard to the position which these other radicals 

 must occupy in order to cause the replacement of bromine by hydrogen, 

 when the compound is treated with tin and hydrochloric acid. 



After we had found, as just described, that the bromine was i"e- 

 nioved by the action of tin and hydrochloric acid upon tribromdinitro- 

 benzol, we turned our attention to the study of the bromine derivatives 

 of metaphenylene diamine, as only one of these had been described, — 

 a dibromphenylene diamine, which Hollemann * stated he had obtained 

 by the action of bromine water on the chloride of phenylene diamine. 

 He gives, however, neither melting point nor analysis of his substance. 

 Upon trying to repeat his preparation we found that bromine water 

 converted the chloride of phenylene diamine (or the free base sus- 

 pended in water) into a tribiomphenylene diamine melting at 158°. 

 As the product is the same, when an insufficient quantity of bromine 

 is used, a portion of the phenylene diamine remaining unaltered in this 

 case, the statement of Hollemann must have rested on an error of 

 observation. A paper by Vaubehf which appeared after our work on 

 this subject was finished, confirms our result, as he found by a volu- 

 metric method that three atoms of bromine are substituted for hydro- 

 gen in the molecule of phenylene diamine, when it is treated with a 

 mixture of potassic bromide, sulphuric acid, and potassic bromate. 

 We have made the same tribromphenylene diamine by the action of 

 zinc dust and acetic acid on the tribromdinitrobenzol ; this method of 

 prepai-ation proves that its constitution is Br. NHg. Br. NHo. Br. H. 



A dibromphenylene diamine can be obtained by the action of bro- 

 mine in excess upon phenylene diacetamide. The dibromphenylene 

 diacetamide melts at 259° to 260° ; the free base at 135°. We have 

 not succeeded in determining the constitution of this dibromphenylene 

 diamine. Nor have we obtained the corresponding monobromphenylene 

 diamine. A monobromphenylene diamine belonging to another series 

 was obtained, however, by reducing tetrabromdinitrobenzol melting 

 point 227° with tin and hydrochloric acid ; it melts at 93°- 94°, and 

 from our experiments on the reduction of tribromdinitrobenzol there 

 can be little doubt that it has the symmetrical constitution Br. H. 

 NH,. H. NH,. H. When treated with bromine three atoms are sub- 



* Zeitschr. f. Chem. 1865, p. 555. 



t Journ. Prakt. Chem. [2] XL VIII. 75. 



