1] In this work, we use computational chemistry at the B3LYP/6-31g* level of theory combined with Pinnock's cloudy sky instantaneous radiative transfer model to predict radiative forcing for hydrofluoroether compounds. We validate our predictive ability using the 27 values of cloudy sky radiative forcing reported in the literature before populating a database of 25 other hydrofluoroethers where no radiative forcing data is available. These additional compounds were selected because kinetic data are available for them and one could predict global warming potentials using the work reported here.

No abstract

Global warming potentials are estimated for hydrofluoroethers, which are an emerging class of compounds for industrial use. Comparisons are made to the limited data previously available before observations about molecular design are discussed. We quantify how molecular structure can be manipulated to reduce environmental impacts due to global warming. We further highlight the need for additional research on this class of compounds so environmental performance can be assessed for green design.

Density functional calculations at the B3LYP/6-31g* level of theory are used to predict gas-phase heat capacities as a function of temperature for the two-carbon hydrofluoroethers and dimethyl ether. We use equilibrium thermodynamic calculations to determine weighting factors for different rotameric forms to find an observable heat capacity estimate. Hindered rotor corrections were made to the partition functions for these weightings and for the heat capacity contributions for the modes where the harmonic oscillator approximation was inappropriate. We find close agreement with experimental values for the two hydrofluoroethers where heat capacities have been measured and good agreement over a wide temperature range for dimethyl ether. This agreement indicates that the heat capacities we report for the other seven species are accurate and would represent experimental data if it were available in the open literature. This work populates a needed database for the evaluation of these materials as heat transfer media in the temperature range from 100 to 3000 K.