172 ABIOGENIC ORGANIC-CHEMICAL EVOLUTION 



acid formed from acetylene and carbon monoxide at 115° C 

 and 100 atmospheres goes on to form succinic acid according 

 to the equation 



CO 



CH2 = CH.COOH >HOOC.CH2.CH2.COOH 



HoO 



Oxo syntheses can occur with any unsaturated compounds, 

 including aromatic ones. 



Under the conditions prevailing in the primaeval litho- 

 sphere many reactions leading to the formation of nitrogen- 

 ous substances could also occur. In addition to the formation 

 of methylamine as described above, we must now mention 

 the formation of ethylamine and acetonitrile by the catalytic 

 condensation of acetylene and ammonia when they pass over 

 bauxite, permutite or other catalysts at 400° C. 



Long ago Berthelot described the synthesis of pyrrole and 

 other nitrogenous heterocyclic compounds as the result of 

 the action of acetylene on ammonia, diazomethane and 

 hydrocyanic acid. A. Chichibabin''^ has shown that pyrrole 

 and some pyridine bases are formed from acetylene and 

 ammonia in the presence of AioOg, FeaOs, or CroOg at 300° C. 



CH - CH 



,f;H II II 



2 III +NH3 > CH CH -fHo 



CH \ / 



NH 



Similar syntheses have been described in detail by A. P. 

 Terent'ev and L. A. Yanovskaya.^^ T. Ishiguro, S. Kubota, 

 O. Kimura and S. Shimomura^^ have recently described 

 experiments in which they obtained pyridine (C5H5N) and 

 its homologues by condensing acetylene and ammonia in 

 the presence of various catalysts at temperatures of about 

 300 - 400° C. 



Most of the reactions which have just been mentioned 

 can easily be carried out in the laboratory or on an industrial 

 scale for the manufacture of one or other of the products. 

 Their occurrence, however, cannot by any means always be 

 observed in nature, as it is now complicated and obscured 

 by the changes taking place in carbon compounds which have 



