104 PROCEEDINGS OP THE AMERICAN ACADEMY 



an energetic substance as methylene must be expected to be might 

 polymerize at 100°. 



Although methylene or its homologues have not as yet been iso- 

 lated, there are a number of known substances which possibly may 

 contain bivalent carbon, as, for instance, prussic acid, HN=0, its 

 salts, and the so called carbylamines, BrNO, or isonitriles, which 

 were discovered by Gautier * and Hofmann.f I have therefore 

 undertaken, in the first place, a very thorough study of these 

 substances, in order to prove by experiment, if possible, whether 

 bivalent carbon is present or absent; and in case bivalent carbon 

 is present, and its properties thus have become more exactly 

 known, to attempt further the isolation of methylene or of its 

 homologues ; the latter substances naturally may be expected to be 

 still more reactive than prussic acid or the carbylamines. 



From the experiments which I have the honor to present to the 

 Academy in this first paper, it will be seen that the presence of 

 bivalent carbon in the carbylamines, KN=C = , has been proved with 

 great precision, and, further, it has become very probable that 

 prussic acid has the formula H-N=C-. The carbylamines are far 

 more reactive than the ordinary define and acet} r lene derivatives, 

 but they do not yet equal sodic acetacetic ether in energy of re- 

 action. Prussic acid, on the other hand, shows, as far as can be 

 judged now, a reactivity which is not much different from that 

 shown by the ordinary unsaturated compounds, — facts which are 

 entirely in accord with the ideas developed above. 



The experiments on the isonitriles have been carried out prin- 

 cipally with phenyl and o-tolylisocyanide. The following addition 

 products have been obtained thus far, and their constitution proved. 

 The reactions are given using the general expression BrNO, 

 where R denotes either 



C 6 H 5 or C 6 H 4 ( CH3 g. 



1. Halogens (X 2 ) react at — 15°, with great evolution of heat, 



as follows : 



R-N=C= + X 2 = RN=OX 2 . 



2. Hydrochloric acid reacts with explosive violence at — 15°, 

 which is avoided, as in case 1, by suitable dilution, and there are 

 formed addition products of the general formula: 



* Annates de Chim. et de Phys., [4.], XVII. 205. 

 t Ann. Chem. (Liebig), CXLIV. 114, CXLVI. 107. 



