CONTRIBUTIONS FROM THE CHEMICAL LABORATORY 

 OF HARVARD COLLEGE. 



JsOTE ON THE CONSTITUTION OF DIPARABROMBEN- 



ZYLCYANAMIDE. 



By C. Lorixg Jackson and R. W. Fuller. 



Received Norember 24, 1899. Presented December 13, 1899. 



The work described in this paper consists of the conversion of the 

 silver salt of cyanamide into a dialkylcyanamide, and the determination 

 of the coustitutiou of this body. Last summer (after this work was 

 finished) a paper a|ipeared in the " Berichte der deutschen chemischen 

 Gesellschaft," in which Wallach * described a number of substituted 

 cyanamides obtained by the action of bromide of cyanogen on secondary 

 amines. For fear of approaching too near the field thus reserved by 

 Wallach we shall abandon the further study of dialkylcyanamides, but 

 the study of alkyl compounds of dicyandiamide and dicyanimide will be 

 taken up in this Laboratory ; in fact work on this latter substance is 

 already in progress. 



Theoretically a dialkylcyanamide derived from the silver salt of 

 cyanamide might have either of the following formulas R-N=C=N-R or 

 R.rN-CN, and it is easy to determine by experiment which of these two 

 formulas is correct. So far as we can find, but a single experiment of 

 this sort has been tried ; this was published some years ago by Fileti and 

 Robert Schiff,t who prepai'ed diethylcyanaraide by the action of ethyl- 

 iodide on argentic cyanamide at 100° for some hours. The product was 

 extracted with ether, and divided into two portions ; one was distilled, 

 and gave a boiling point of 186°, whereas Cloez and Cannizzaro, J who 

 prepared it by the decomposition of ethyl cyanamide, found a boiling 

 j)oint of 190°. Fileti and R. Schiff analyzed their distillate, and ob- 

 tained carbon 60.66 instead of 61.22 and hydrogen 10.11 instead of 10.30. 



* Ber. d. chem. Ges., XXXIL 1872. 

 t Id., X. 425 (1877). 

 t Ann. Chem., XC. 95. 



