TY - GEN
T1 - Prediction of global warming potentials through computational chemistry - Testing robustness of methodology through experimental comparisons
AU - Blowers, Paul
AU - Hollingshead, Kyle
PY - 2008
Y1 - 2008
N2 - Global warming is a scientifically based concern regarding addition of naturally occurring and anthropogenic chemicals to the troposphere where the species can trap infrared energy. Predicting global warming potentials requires highly accurate rate constant measurements for the reactions of the chemicals with hydroxyl radicals, which is the first and rate limiting step in tropospheric degradation. Radiative forcing, the amount of energy that can be captured by the chemicals per square meter of exposed area for a given concentration, requires spectroscopic information about peak locations and intensities, which are then aggregated into absorption cross sections. These values are then used in atmospheric modeling simulations to determine the radiative forcing. Both kinetic and spectroscopic measurements have many potential experimental difficulties, which makes predicting global warming potentials (GWPs) from theory attractive. We build on our previous work by examining an emerging class of compounds, fluorinated ethers, using theoretical chemistry to predict GWPs. Previous work investigated CH2F2 and found excellent comparison to experiment for predicting all intermediate steps for GWPs, including kinetic degradation rates with hydroxyl radical under low temperature tropospheric conditions, atmospheric lifetime estimates, radiative forcing in the atmospheric window, and overall GWPs at 20 year, 100 year, and 500 year time horizons. We find good agreement for all parameters for the hydrofluoroethers compared to experimental values. Radiative forcing estimates are also in good agreement with available experimental results. Finally, we now have a larger database of chemicals where we have verified our methodology of accurately predicting global warming potentials using theory.
AB - Global warming is a scientifically based concern regarding addition of naturally occurring and anthropogenic chemicals to the troposphere where the species can trap infrared energy. Predicting global warming potentials requires highly accurate rate constant measurements for the reactions of the chemicals with hydroxyl radicals, which is the first and rate limiting step in tropospheric degradation. Radiative forcing, the amount of energy that can be captured by the chemicals per square meter of exposed area for a given concentration, requires spectroscopic information about peak locations and intensities, which are then aggregated into absorption cross sections. These values are then used in atmospheric modeling simulations to determine the radiative forcing. Both kinetic and spectroscopic measurements have many potential experimental difficulties, which makes predicting global warming potentials (GWPs) from theory attractive. We build on our previous work by examining an emerging class of compounds, fluorinated ethers, using theoretical chemistry to predict GWPs. Previous work investigated CH2F2 and found excellent comparison to experiment for predicting all intermediate steps for GWPs, including kinetic degradation rates with hydroxyl radical under low temperature tropospheric conditions, atmospheric lifetime estimates, radiative forcing in the atmospheric window, and overall GWPs at 20 year, 100 year, and 500 year time horizons. We find good agreement for all parameters for the hydrofluoroethers compared to experimental values. Radiative forcing estimates are also in good agreement with available experimental results. Finally, we now have a larger database of chemicals where we have verified our methodology of accurately predicting global warming potentials using theory.
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M3 - Conference contribution
AN - SCOPUS:80053778241
SN - 9780816910236
T3 - AIChE Annual Meeting, Conference Proceedings
BT - 2008 AIChE Spring National Meeting, Conference Proceedings
T2 - 2008 AIChE Spring National Meeting, Conference
Y2 - 6 April 2008 through 10 April 2008
ER -