Laser photolysis of 2-propanone, 2-butanone, 3-pentanone and 3-buten-2-one in the gas phase

Article abstract of DOI:10.1016/S0040-4020(97)00096-3

Low fluence (25 mJ.cm.^-2) and high fluence (180 mJ.cm^-2) ArF laser (193.3 nm) photolysis of R₁C(O)R₂, (R₁, R₂ = CH₃, C₂H₅, C₂H₃) afford carbon monoxide and hydrocarbons which are in the former case mostly R₁-R₂ alkanes and in the latter case R₁-R₂ alkanes along with methane, ethene and ethyne. The effect of excess of helium and hydrogen suggests that the products preferred at the high-fluence result from reactions of hot CH₃· radicals, and disproportionations of C₂H₅· and cross disproportionation of CH₃· radicals. No effect of radical scavenging [²H₄]germane an the course of the low-fluence photolysis is judged to reflect high energy content of R₁ and R₂ radicals.