CHAPTER V 



ABIOGENIC ORGANIC-CHEMICAL 

 EVOLUTION OF CARBON COMPOUNDS 



Thermodynamics and kinetics of the transformation 

 of the simplest hydrocarbons in the lithosphere, 

 atmosphere and hydrosphere of the Earth. 



As was pointed out at the end of Chapter IV, the Earth, 

 during a considerable period of its existence, was devoid of 

 Hfe. During a substantial part of this time, those many 

 millions of years which separate the time of the formation 

 of the Earth from the appearance of life on it, there took 

 place the abiogenic, organic-chemical evolution of carbon 

 compounds. Hydrocarbons and their simplest nitrogen- and 

 oxygen-containing derivatives began to be found on the 

 surface of the Earth, as has been shown above, at the very 

 earliest stage of its existence. However, these compounds 

 were only the starting point, the first link in a long chain of 

 diverse organic-chemical reactions which now began and 

 Avhich led to the formation in the atmosphere and the hydro- 

 sphere of the Earth of a large number of varied compounds, 

 some of which were of complicated structure and high mole- 

 cular weight, similar to the substances entering into the 

 composition of present-day animals and plants. 



The basic requirements for this second stage of the 

 development of matter from the simplest hydrocarbons to 

 the most complicated organic compounds were inherent in 

 the original hydrocarbons themselves. Hydrocarbons possess 

 enormous chemical potentialities. It is with good reason 

 that the whole of organic chemistry is today regarded as the 

 chemistry of hydrocarbon derivatives. The diagram (Fig. 

 ii),^ showing the free energies of formation of organic com- 

 pounds, demonstrates clearly the thermodynamic possibility 

 of the passage from hydrocarbons to their oxygen- and 

 nitrogen-containing derivatives. Polymerisation and con- 

 densation of these derivatives could then give rise to more 



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