The Role of Hydrogen Cyanide in Chemical Evolution

Abstract

Two major research areas are investigated: The electrosynthesis of hydrogen cyanide; and the role of cyanocomplexes in the free - radical oligomerization of hydrogen cyanide. The electric discharge production of hydrogen cyanide from a simulated primitive atmosphere composed of methane, nitrogen and water vapor was investigated. The radiation chemical yield (G) of formation of HCN was determined to be 0.26. A free radical mechanism was proposed to account for the observed chemical changes. Computer simulations of the reaction mechanism could effectively model the early stages of electrolysis of the gas mixture, and permitted the estimation of the rate of electrosynthesis of hydrogen cyanide under various atmospheric conditions . The possible role of cyanocomplexes of transition elements on the free- radical oligomerization of hydrogen cyanide was investigated. Aqueous, oxygenfree, dilute solutions of hydrogen cyanide and hexacyanoferrate(II) or (III) were submitted to various doses of gamma irradiation. The presence of either cyanocomplex led to a significant decrease in the rate of decomposition of hydrogen cyanide. The major products were ammonia and carbon dioxide . Computer simulations of these systems permitted the elucidation of the reaction mechanism and the derivation of rates of reactions of free- radicals with the cyanocomplexes. The results obtained provide an insight into the possible role of cyanocomplexes of transition elements in chemical evolution.