A theoretical investigation of decomposition and reactivity of the atmospheric C3F7OCH2O radical

The present theoretical investigation involves the ab initio quantum mechanical study of the decomposition and reactivity mechanism of the C3F7OCH2O radical that is formed from HFE-7000. Geometry of reactants, products and transition states were optimized at B3LYP and B3PW91 levels of theory with 6-311G(d,p) basis set. Five important pathways for decomposition and reactivity of C3F7OCH2O were investigated: reaction with atmospheric O2, reaction with atmospheric OH radical, C-O bond cleavage, H elimination and the migration of hydrogen from carbon to oxygen and then C-O bond cleavage with energy barriers of 4.3, 12.6, 17.1, 20.0 and 32.4 kcal mol−1, respectively. Rate constants were calculated by utilizing the canonical transition state theory (CTST) in the range of 200-400 K and the Arrhenius diagrams have been plotted. From the obtained results, it was concluded that reaction with atmospheric O2 is a dominant pathway for the consumption of the C3F7OCH2O radical in the atmosphere. Intrinsic reaction coordinate (IRC) calculation was performed to confirm the existence of transition state on the corresponding potential energy surface.