Estimating the capacity for production of formamide by radioactive minerals on the prebiotic Earth.
Sci Rep
; 8(1): 265, 2018 01 10.
Article
en En
| MEDLINE
| ID: mdl-29321594
Water creates special problems for prebiotic chemistry, as it is thermodynamically favorable for amide and phosphodiester bonds to hydrolyze. The availability of alternative solvents with more favorable properties for the formation of prebiotic molecules on the early Earth may have helped bypass this so-called "water paradox". Formamide (FA) is one such solvent, and can serve as a nucleobase precursor, but it is difficult to envision how FA could have been generated in large quantities or accumulated in terrestrial surface environments. We report here the conversion of aqueous acetonitrile (ACN) via hydrogen cyanide (HCN) as an intermediate into FA by γ-irradiation under conditions mimicking exposure to radioactive minerals. We estimate that a radioactive placer deposit could produce 0.1â0.8 mol FA km-2 year-1. A uraninite fission zone comparable to the Oklo reactors in Gabon can produce 0.1â1 mol m-2 year-1, orders of magnitude greater than other scenarios of FA production or delivery for which reaching sizeable concentrations of FA are problematic. Radioactive mineral deposits may be favorable settings for prebiotic compound formation through emergent geologic processes and FA-mediated organic chemistry.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
Sci Rep
Año:
2018
Tipo del documento:
Article
País de afiliación:
Estados Unidos