Hydroxyacetonitrile (HOCH2CN) formation in astrophysical conditions. competition with the aminomethanol, a glycine precursor

Abstract

This contribution is focused on the concurrent pathway to the Strecker synthesis of amino acids in an astrophysical-like environment. We indeed use experimental and modeling simulations to investigate the possibility to form the aminomethanol (HOCH2NH2) in concurrence with the hydroxyacetonitrile (HOCH2CN) from ices containing at 40K formaldehyde (CH2O), ammonia (NH3), and cyanide ion (CN-). We demonstrate using infrared spectroscopy and mass spectrometry that the formation of the aminomethanol (Ea = 4.5kJmol-1) is competing with the hydroxyacetonitrile formation (Ea = 3.9kJmol-1). The ratio between aminomethanol and hydroxyacetonitrile depends on the initial ratio in the ice between ammonia and cyanide. An increase of cyanide ion provides a decrease in aminomethanol formation. Since the aminomethanol is the first step through the formation of glycine in astrophysical environments, these data are important for understanding the possibility of forming glycine in such environments. Furthermore, using a reduced kinetic model, we evaluate the astrophysical environments in which the aminomethanol and hydroxyacetonitrile can be formed and evolved without degradation. The results suggest that these two molecules could be formed in molecular clouds or protostellar disks, and subsequently incorporated inside comets or asteroids. Therefore, hydroxyacetonitrile and aminomethanol could be formed before the formation of the solar system, which suggests that hydroxyacids and amino acids, such as those detected inside meteorites, have been formed in various astrophysical environments. © © 2012. The American Astronomical Society. All rights reserved..