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.