Photochemical Synthesis of Ammonia and Amino Acids from Nitrous Oxide.

Abiotic synthesis of ammonia (NH3) and amino acids is important for the origin of life and early evolution. Ammonia and organic nitrogen species may be produced from nitrous oxide (N2O), which is a second abundant nitrogen species in the atmosphere. Here, we report a new photochemical experiment and evaluate whether N2O can be used as a nitrogen source for prebiotic synthesis in the atmosphere. We conducted a series of experiments by using a gas mixture of N2O+CO, N2O+CO2, or N2O + H2 in the presence of liquid water. The results demonstrate that NH3, methylamine (CH3NH2), and some amino acids such as glycine, alanine, and serine can be synthesized through photochemistry from N2O even without metal catalysts. NH3 can be produced not only from CO + N2O, but also from H2+N2O. Glycine can be synthesized from CH3NH2 and CO2, which can be produced from N2O and CO under ultraviolet irradiation. Our work demonstrates, for the first time, that N2O could be an important nitrogen source and provide a new process for synthesizing ammonia and organic nitrogen species, which has not been previously considered. The contribution of organic synthesis from N2O should, therefore, be considered when discussing the prebiotic chemistry on primitive Earth.