THE EFFECT OF LEWIS-ACID CATALYSIS ON THE DECOMPOSITION OF CF3OCF3 TOCOF2 AND CF4

The CF3OCF3 and AlF3 Lewis acid interaction is investigated by ab init io theory to explain the catalytically enhanced degradation of polyper fluorinated ether lubricants. Thus, an understanding of the Lewis acid interaction in these materials is gained by investigating the optimiz ed geometries of CF3OCF3 in the presence and absence of AlF3. The comp uted bond parameters and partial atomic charges identify a strong inte raction between the aluminum substrate and the CF3OCF3 ether oxygen at om. 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 in teraction is computed, providing a quantitative understanding for cata lytically induced degradation in these materials. (C) 1997 Elsevier Sc ience S.A.