JACKSON AND FULLER. — DIPARABROMBEXZYLCYANAMIDE, 235 



A number of experiments were tried in the hope of obtaining polymeres 

 of the diparubrombenzylcyanamide. A dilute solution of sodic or potas- 

 sic hydrate produced no effect on the substance, either by long standing 

 in the cold or by boiling the mixture. The substance was boiled for two 

 weeks with a solution of ammoiiic hydrate, care being taken to replace the 

 ammonia which escaped, but the only change observed was that the color 

 turned from white to pale brown, evidently due to a slight decomposition, 

 since the melting point of the substituted cyanamide was essentially unal- 

 tered. Water alone was also tried at the boiling point, but produced no 

 chano-e. Upon heating the substance above its melting point it remained 

 unaltered to 160° ; above this point it turned first yellow, and at higher 

 temperatures red, and on cooling gave an oily product, which we could 

 not bring into a fit state for analysis. A similar viscous product was ob- 

 tained when the substance was heated with sodic acetate. In both these 

 cases it seemed evident that a decomposition had taken place rather than 

 a polymerization, and our experiments, therefore, confirm the statement of 

 Wallach that these dialkylcyanamides show no tendency to polymerize. 



DECOMPOSITIOlSr OF DiPARABROMBENZYLCYANAMIDE. 



As some preliminary experiments showed that the substituted cyan- 

 amide was decomposed with difficulty by hydrochloric acid in open vessels, 

 we adopted a dilute sulphuric acid having a specific gravity of 1.44, 

 which has frequently given good results in this Laboratory. Several 

 grams of the diparabrombenzylcyanamide were boiled with a large excess 

 of this acid in a flask with a return-condenser. Soon after the substance 

 melted in the hot acid an effervescence was observed, and upon testing 

 the gas given off with baryta water, it proved to be carbonic dioxide. 

 As the oily drops did not disappear, the heating was continued for ten 

 hours, which reduced the amount of oil, but did not entirely remove it. 

 On cooling, the whole liquid became filled with a voluminous white crys- 

 talline precipitate ; we determined, therefore, to stop the process at this 

 point and isolate this crystalline sul)Stance, which could be easily separated 

 from the portion undissolved in the hot sulphuric acid. This latter sub- 

 stance which solidified on cooling, seemed to consist of undecomposed 

 diparabrombenzylcyanamide, as it gave a fresh quantity of tlie crystalline 

 product on boiling again with sulphuric acid ; its amount was insignifi- 

 cant. To obtain the crystalline pro<luct it was filtered from the acid 

 liquid, washed with a little cold water to free it from adhering acid, and 

 then dissolved in hot water, which left behind the few black lumps of 

 undecomposed cyanamide. The solution was then filtered, and the sul- 



