Insight into the high-temperature oxidation kinetics of acetylene: A first-principles molecular dynamics study.

The study on high-temperature oxidation kinetics and kinetic modeling of acetylene (C 2 H 2) has significant importance for its engineering applications. In this paper, the first-principles molecular dynamics method is used to simulate the C 2 H 2 oxidation under high temperatures for the first time. Our results show that there are 38 intermediates and 225 elementary reactions in the process of C 2 H 2 oxidation. The formation mechanisms of "prompt" CO 2 , as well as gas pollutants CHOCHO and HCOOH are revealed in depth. Four intermediates, CHCHO, CHOCO, CHOCHO and HCOOH, which have significant controversy in current kinetic models, are verified. And a new intermediate, CHOCO 2 , is discovered. Meanwhile, our simulation also shows that radicals, such as HO 2 , OH, O, etc. play a key role in promoting the oxidation of intermediates in the early stage of C 2 H 2 oxidation. Combined with quantum chemical calculations, a detailed chemical kinetic model of C 2 H 2 /air (FP-C 2 H 2) is built and verified by simulating ignition delay time, species concentration in the flow reactor and premixed laminar flame speed. Our studies provide novel insight for understanding the complex chemical reaction kinetics, and environmental and human health threats from air pollutant formation during C 2 H 2 combustion. [Display omitted] ● The formation mechanism of gas pollutants CHOCHO and HCOOH are revealed. ● Intermediates CHOCO, HCOOH, CHOCHO and CHCHO are key species to C 2 H 2 combustion. ● The decomposition of new intermediate CHOCO 2 explains the prompt CO 2 formation. ● 38 intermediates and 225 elementary reactions are discovered by FPMD simulation. ● A detailed chemical kinetic model of C 2 H 2 combustion is constructed and verified. [ABSTRACT FROM AUTHOR]