A better understanding of auto-oxidation reaction mechanisms could lead to better engines, less air pollution, and improved climate models.
Oxygen plays a key role in chemical reactions that produce pollutants in the atmosphere and that fuel combustion engines. In these reactions, auto-oxidation (spontaneous oxidation in air or in the presence of oxygen) produces highly oxygenated molecules.
For example, volatile organic compounds (VOCs)—gas molecules emitted from vehicles, factories, and power plants (as well as living plants)—undergo a sequence of auto-oxidation reactions with the surrounding air, forming highly oxygenated molecules that contribute to air pollution, affecting health and climate. The same highly oxygenated molecules are also produced during the ignition of fuels in advanced combustion engines; controlling their formation and destruction processes can help to develop higher-efficiency engines.
However, because these highly oxygenated molecules are very reactive and decompose quickly, determining their identities has been difficult.
Image: Illustration of the jet-stirred reactor used in this experiment. Jet nozzles in the reaction chamber (center) generate turbulence for mixing the incoming fuel molecules with oxidizer (lower right). After the fuels react, the products exit the apparatus (upper left) to be analyzed by advanced mass spectrometry.
Credit: Ahmed Najjar