The relative rate constants of oxygen, O(3P), atoms with different gaseous unsaturated compounds at room temperature

Abstract

A simple method is proposed in order to measure the relative rate constants of the interactions between oxygen O(3P) atoms and unsaturated hydrocarbon. A 147 nm photolysis of air is used to produce the O(3P) atoms. In the presence of 1,2-butadiene, these oxygen atoms have a very clean reaction that gives rise to propylene formation. By including a suitable additive, and by looking at the formation of propene versus the [additive]/[1,2-butadiene] ratio, the absolute values of the various O(3P) + unsaturated hydrocarbon interactions can be evaluated. These rate constants increase with the number of substituents attached to the double bond. Moreover, a correlation between the total rate constants and ionization potentials is also observed.