The Polymerization of Ethylene Photosensitized by 51P1 Cadmium Atoms

Abstract

An investigation has been made of the reactions of ethylene photosensitized by 5¹P₁ cadmium atoms, i.e., using the resonance line at 2288A. It is found that reaction occurs readily, in contrast to the action of 5³P₁ atoms, which have been previously shown to be ineffective. The products of the reaction are butene, hexene, and higher olefins, together with smaller amounts of acetylene and hydrogen. No pressure rise is detectable in the early stages of the reaction, and acetylene is a much less important product than is the case with mercury photosensitization. It is concluded that the primary step may be either $$\mathrm{Cd}{(}^1{P}_1\mathrm{)+}{\mathrm{C}}_2{\mathrm{H}}_4=\mathrm{Cd}{(}^1{S}_0\mathrm{)+}{\mathrm{C}}_2{\mathrm{H}}_3+\mathrm{H}$$ or $$\mathrm{Cd}{(}^1{P}_1\mathrm{)+}{\mathrm{C}}_2{\mathrm{H}}_4=\mathrm{Cd}{(}^1{S}_0\mathrm{)+}{\mathrm{C}}_2{\mathrm{H}}_4^{*}.$$ Subsequent polymerization probably occurs by a free radical mechanism.