Thermal wet decomposition of Prussian Blue: implications for prebiotic chemistry.
The complex salt named Prussian Blue, Fe4[Fe(CN)6]3 x 15 H2O, can release cyanide at pH > 10. From the point of view of the origin of life, this fact is of interest, since the oligomers of HCN, formed in the presence of ammonium or amines, leads to a variety of biomolecules. In this work, for the first time, the thermal wet decomposition of Prussian Blue was studied. To establish the influence of temperature and reaction time on the ability of Prussian Blue to release cyanide and to subsequently generate other compounds, suspensions of Prussian Blue were heated at temperatures from room temperature to 150 degrees at pH 12 in NH3 environment for several days. The NH3 wet decomposition of Prussian Blue generated hematite, alpha-Fe2O3, the soluble complex salt (NH4)4[Fe(CN6)] x 1.5 H2O, and several organic compounds, the nature and yield of which depend on the experimental conditions. Urea, lactic acid, 5,5-dimethylhydantoin, and several amino acids and carboxylic acids were identified by their trimethylsilyl (TMS) derivatives. HCN, cyanogen (C2N2), and formamide (HCONH2) were detected in the gas phase by GC/MS analysis.
Centro de Astrobiología (Consejo Superior de Investigaciones Científicas-Instituto Nacional de Técnica Aeroespacial (CSIC-INTA)), Carretera Torrejón-Ajalvir, Km. 4.2, ES-28850 Torrejón de Ardoz, Madrid. ruizbm@inta.es
Marta
M
Ruiz-Bermejo
Celia
C
Rogero
César
C
Menor-Salván
Susana
S
Osuna-Esteban
José Angel
JA
Martín-Gago
Sabino
S
Veintemillas-Verdaguer
D000641:Ammonia / Q000737:chemistry; D003486:Cyanides / Q000737:chemistry; D005295:Ferrocyanides / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration
D003486:Cyanides; D005295:Ferrocyanides; D000641:Ammonia; C000170:ferric ferrocyanide