Gamma radiation has the ability to convert methane into a variety of different products at room temperature, including hydrocarbons, oxygen-containing molecules, and amino acids. This process, studied by a research team led by Weixin Huang at the University of Science and Technology of China, may play an important role in the formation of complex organic molecules in the universe and potentially in the origins of life. The team’s research also opens up new possibilities for converting methane into high value-added products in industrial settings under mild conditions.
By studying the reactions of methane under irradiation with a cobalt-60 emitter at room temperature in both gas and aqueous phases, the team found that the composition of the products varied depending on the starting materials. Pure methane reacted to form ethane, propane, and hydrogen with low yield, while the addition of oxygen resulted in increased conversion, producing mainly CO2, CO, ethylene, and water. The presence of water led to the formation of acetone and tertiary butyl alcohol in the aqueous phase, and ethane and propane in the gas phase. When water, oxygen, and ammonia were all present, the reactions were accelerated, leading to the formation of glycine, an amino acid found in space.
The team developed a reaction scheme to explain how the individual products were formed, with oxygen radicals playing a crucial role in the process. These radical reaction mechanisms, unaffected by temperature, could potentially occur in space as well. Additionally, the team found that solid particles commonly found in interstellar dust, such as silicon dioxide, iron oxide, magnesium silicate, and graphene oxide, influenced the product selectivity of the reactions. This diversity in interstellar dust composition may have contributed to the uneven distribution of molecules observed in space.
The presence of gamma radiation as an accessible, safe, and sustainable energy source suggests a new approach for converting methane into value-added products under mild conditions. This research could provide a solution to the challenge of efficiently utilizing methane as a carbon source for industrial synthetic chemistry. Overall, the team’s findings contribute to our understanding of the early development of molecules in the universe and shed light on potential pathways for the industrial conversion of methane into valuable products.