Carbonyl Oxide Stabilization from Trans Alkene and Terpene Ozonolysis

The pressure dependence of carbonyl oxide (Criegee intermediate)
stabilization can be measured via H2SO4 detection
using chemical ionization mass spectrometry. By selectively scavenging
OH radicals in a flow reactor containing an alkene, O3,
and SO2, we measure an H2SO4 ratio
related to the Criegee intermediate stabilization, and by performing
experiments at multiple pressures, we constrain the pressure dependence
of the stabilization. Here, we present results from a set of monoterpenes
as well as isoprene, along with previously published results from
tetramethylethylene and a sequence of symmetrical trans alkenes. We
are able to reproduce the observations with a physically sensible
set of parameters related to standard pressure falloff functions,
providing both a consistent picture of the reaction dynamics and a
method to describe the pressure stabilization following ozonolysis
of all alkenes under a wide range of atmospheric conditions.