Thermochemistry of Fluorinated Dimethyl and Ethyl Methyl Ethers and Corresponding Radical Species

Abstract

Standard enthalpies of formation (ΔfH°298), standard entropies (S°(T)), and heat capacities (Cp(T)) are calculated for dimethyl and ethyl methyl fluorinated ethers, both the parent and related radical species. The parent and radical species are utilized to determine carbon–hydrogen, carbon–fluorine, carbon–carbon, and carbon–oxygen bond dissociation energies (C–H, C–F, C–C, and C–O BDEs). The ΔfH°298 and BDEs are calculated using a variety of error-canceling isogyric and/or isodesmic reactions at the MN15/cc-pVTZ, CBS-QB3, and CBS-APNO levels of theory. ΔfH°298 calculations from the MN15 functional for these ether species are shown to have consistency with the CBS-QB3 and CBS-APNO composite methods with our recommended ideal gas phase ΔfH°298 values from the average of these two composite methods. C–F BDE values are shown to range overall between 111 and 128 kcal mol–1, the C–H BDEs are in the 93–106 kcal mol–1 range, the C–O BDEs are in the 83–107 kcal mol–1 range, and the C–C BDEs are in the 88–101 kcal...