M. Kaschke et al., [FES FES(2)] - A REDOX SYSTEM FOR THE ORIGIN OF LIFE - (SOME EXPERIMENTS ON THE PYRITE-HYPOTHESIS)/, Origins of life and evolution of the biosphere, 24(1), 1994, pp. 43-56
The FeS/FeS2 redox system, whose importance is stressed in recent theo
ries on the origin of life, has been tested experimentally. In this pa
per it is demonstrated by thermodynamical calculations as well as by e
xperiments, that cyclohexanone, which served as model compound, can be
reduced by the aforementioned redox system. Reactions were carried ou
t in methanol and DMF at 25-degrees-C and at 100-degrees-C. Besides pr
oducts that were synthesised in both solvents, like cyclohexanethiol a
nd dicyclohexyldisulphide, special compounds were obtained in methanol
and in DMF, because of the involvement of the respective solvent in t
he reaction. Yields of reduced compounds were lower in methanol owing
to a compound that hindered the reduction (cyclohexylketal). With incr
easing temperature and duration the amount of reduced compoinds increa
sed. Further experiments have shown that 1,1-cyclohexanedithiol is lik
ely to be a necessary intermediate for the reduced products. The exper
iments give evidence to the 'pyrite hypothesis', which postulates that
the FeS/FeS2 redox system was of importance for the origin of life.