M. Berthclot on Polymers of Acetylene. 453 



thus carbon and hydrogen unite directly to form acetylene, which 

 forms oxalic acid with free oxygen. 



Ethylene is also oxidized to oxalic acid by permanganate, with 

 elimination of hydrogen, 



G 2 H 4 + 5 =G 2 H 2 9 4 + H 2 G. 



Allylene, C 6 H 4 , in like manner, when treated with permanga- 

 nate, takes up oxygen and forms malonic acid, 



G 3 H 4 + 4 =G 3 H 4 4 , 



while at the same time some acetic and carbonic acids are formed 

 from a secondary decomposition of the malonic acid. 



Propylene is oxidized by permanganate with elimination of 

 hydrogen, forming the same products as allylene in even greater 

 quantity. 



Berthelot has published some investigations in which he shows 

 that several compounds of the aromatic series are polymers of 

 acetylene*. He had formerly shown that chloroform is decom- 

 posed by red-hot copper with the formation of acetylene, 



2GHCl 3 + 3Gu=G 2 H 2 + 3GuCl 2 ; 



and that by the same treatment of bromoform a certain quantity 

 of benzole is obtained, thus — 



6G H Br 3 + 9Gu=G 6 H 6 + 9€u Br 2 . 

 Bromoform. Benzole. 



He has now shown that when acetylene is heated alone to a tem- 

 perature near that of the melting-point of glass it is readily 

 changed into polymers. The yellow liquid obtained in this man- 

 ner was subjected to fractional distillation, and an entire series 

 of hydrocarbons obtained, all of which are polymers of acetylene. 

 Almost half the liquid consisted of benzole. It was found to 

 boil at 80° C, formed with chlorine in the sunlight G 6 H 6 "C1 6 ", 

 and treated with fuming nitric acid yielded nitrobenzole, from 

 which aniline was obtained. This formation of nitrobenzole and 

 aniline renders it possible to prove the change of acetylene into 

 benzole, even when so small a quantity of material as 10 cubic 

 centims. of acetylene was used. 



This reaction explains the occurrence of benzole in preparing 

 acetylene by heating organic matters to redness. The author 

 compares the formation of benzole with the change of acetylene 

 into hydride of ethyle, 



Hydride of ethyle . = G 2 H 2 (H 2 ) (H 2 ), 



Benzole .... = G 2 H 2 (G 2 H 2 ) (G 2 H 2 ), 



* Comptes Uendus, vol. lxiii. pp. 4/9 & 515. 



