The effect of Lewis acid catalysis on the decomposition of CF₃OCF₃ to COF₂ and CF₄

Abstract

The CF3OCF3 and AlF3 Lewis acid interaction is investigated by ab initio theory to explain the catalytically enhanced degradation of polyperfluorinated ether lubricants. Thus, an understanding of the Lewis acid interaction in these materials is gained by investigating the optimized geometries of CF3OCF3 in the presence and absence of AlF3. The computed bond parameters and partial atomic charges identify a strong interaction between the aluminum substrate and the CF3OCF3 ether oxygen atom. A transition state that connects the reactant CF3OCF3 and products COF2 and CF4 is identified. The effect of the Lewis acid interaction on the transition state geometry is analyzed. A significant reduction in the activation energy to the transition state via the Lewis acid interaction is computed, providing a quantitative understanding for catalytically induced degradation in these materials. © 1997 Elsevier Science S.A.