Primary processes in the 163.3 nm photolysis of gas-phase ethyl chloride

Abstract

The vacuum UV photolysis of ethyl chloride at 163.3 nm was studied over the pressure range 1 – 77 Torr of the reactant at room temperature using a bromine atom resonance lamp. Pressure effects were investigated with and without the addition of CF 4 or CH 4 and scavenging effects were monitored by addition of NO gas as radical scavenger. The major products of the reaction were CH 4, C 2H 4, C 2H 6, C 3H 8, C 2H 3Cl and n-C 4H 10 formed via two-channel competition between molecular elimination and radical formation. On addition of NO gas, the formation of CH 4, C 2H 6, C 3H 8 and n-C 4H 10 was completely suppressed and formation of C 2H 4 and C 2H 3Cl was reduced. The decomposition modes in the primary process were molecular elimination (25%) and radical reaction (75%). The extinction coefficient of C 2H 5Cl at 163.3 nm was determined to be 27.8 atm −1 cm −1 from the absorption cross-section data.