176 ABIOGENIC ORGANIC-CHEMICAL EVOLUTION 



methane could serve as the basis for the formation of the 

 most varied organic substances. As we have already seen, 

 the direct thermal dehydrogenation of methane requires very 

 high temperatures, at which it cannot polymerise. Under 

 the influence of electrical discharges, on the other hand, 

 methane polymerises easily with the formation of various 

 gaseous, liquid and solid products, as had already been 

 demonstrated by the end of the nineteenth century.^' 



Acetylene, ethylene, diacetylene, benzene, naphthalene, 

 acetonaphthene, dipropargyl and many other hydrocarbons, 

 some of very high molecular weights, have been identified 

 during the study of the composition of these products. Most 

 of the substances listed arise as the result of the secondary 

 transformation of acetylene, which is to be regarded as one 

 of the fundamental products of the dehydrogenation and 

 polymerisation of methane under the influence of electric 

 discharges.'* 



R. V. de St.-Aunay®^ submitted methane to the action of 

 silent discharges in a circulating system and this allowed him 

 to form an opinion as to the earliest stages of the process. On 

 the basis of this work he wrote as follows : 



At the very beginning of the activity of the discharge the 

 methane was split to hydrogen and a free radical which led to 

 a slight decrease in the volume of the gas on condensing. Ethane 

 was formed from methane without any change in volume, 



and as it accumulated it was dehydrogenated, which gave an 

 increase in the volume, CaHg-^CaH^ +H2. The ethylene thus 

 formed was dehydrogenated in its turn. When enough ethylene 

 and acetylene had accumulated a further decrease in volume 

 took place, due to their polymerisation. 



The polymerisation in the electric discharge of ethane, '*® 

 ethylene^'^ and, especially, of acetylene,'^ leads to the forma- 

 tion of a countless variety of compounds both aliphatic and 

 cyclic. This variety of products is greatly increased ^vhen the 

 electric discharges act on mixtures of hydrocarbons, e.g. 

 CoHo-fCH^; CoH^ + CH^;^^ C2H2-fC2H4 ;^'"' C6H6 + CH4/" etc. 

 Unfortunately these reactions have not yet been studied in 

 anything like full detail. 



