Laser-induced oxidation reactions in supercritical ethaneO2 mixtures

Abstract

Abstract The laser-induced oxidation of ethane by O 2 at 318 K was investigated with varying the pressure between 12–91 atm. The reaction condition was regarded as the supercritical phase above 50–60 atm, depending on the O 2 fraction. Ethanol, acetaldehyde, and CO 2 were mainly produced at any reaction conditions, together with small amounts of C 1 compounds and formic esters. The kinetic discussion for the time dependence indicated that the consecutive photolysis of primary products takes place during the subsequent laser irradiation period. The branching ratio to CO 2 formation in the primary process in the supercritical phase is much smaller than that in the gas phase, and the selectivities for ethanol and acetaldehyde show a discontinuous change near the critical point. These facts show that the supercritical phase affects this complex radical reaction system. The primary photoabsorption process is also discussed.