Gaseous and heterogeneous reactions on the mechanisms and kinetics of acrolein with ozone

摘要

In this paper, the gas-phase and heterogeneous reactions of acrolein with ozone were studied comprehensively and deeply. Acrolein is one of the simplest unsaturated aldehydes found widely in the fuel combustion and industrial emissions. Mineral particles produced by frequent sandstorms have important effects on the tropospheric chemistry and the climate change. The content of silica in clay minerals is rich, thus three kinds of clusters (the monomeric model Si(OH)(4), the linear model Si3O2(OH)(8) and the cyclic hexamer model Si6O6(OH)(12)) were selected for the heterogeneous study. The reaction rate constant of acrolein with ozone at 298 K and 1 atm was 7.46 x 10(-18) cm(3) molecule(-1) s(-1), which was in agreement with the experimental value. SiO2 clusters interacted with acrolein via the hydrogen bonds and had good adsorption properties. The hydrogen bond between the oxygen of aldehyde group on acrolein and the hydrogen of silica surface was stronger and the adsorption energy was greater. The adsorption of silanol groups did not change the ozonation mechanism of acrolein, but had effects on the reaction rate. Among them, three silanol groups acted as positive catalysts. The kinetic data within the temperature range of 216.65-288.15 K corresponding to the height of the troposphere at 0-11 km showed that the rate constant of O-3-initiated reaction of acrolein is positively correlated with the temperature. In addition, we also studied the reaction mechanism and kinetic of the Criegee intermediates reacting with atmospheric small molecules and isomerization process in gas-phase and heterogeneous processes.