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Title: Atmospheric chemistry of hydrogen fluoride

Abstract

In this study, the atmospheric chemistry, emissions, and surface boundary layer transport of hydrogen fluoride (HF) is summarized. Although HF is known to be chemically reactive and highly soluble, both factors affect transport and removal in the atmosphere, we suggest that the chemistry can be ignored when the HF concentration is at a sufficiently low level (e.g., 10 ppmv). At a low concentration, the capability for HF to react in the atmosphere is diminished and therefore the species can be mathematically treated as inert during the transport. At a sufficiently high concentration of HF (e.g., kg/s release rate and thousands of ppm), however, HF can go through a series of rigorous chemical reactions including polymerization, depolymerization, and reaction with water to form molecular complex. As such, the HF species cannot be considered as inert because the reactions could intimately influence the plume s thermodynamic properties affecting the changes in plume temperature and density. The atmospheric residence time of HF was found to be less than four (4) days, and deposition (i.e., atmosphere to surface transport) is the dominant mechanism that controls the removal of HF and its oligomers from the atmosphere. The literature data on HF dry deposition velocity wasmore » relatively high compared to many commonly found atmospheric species such as ozone, sulfur dioxide, nitrogen oxides, etc. The global average of wet deposition velocity of HF was found to be zero based on one literature source. Uptake of HF by rain drops is limited by the acidity of the rain drops, and atmospheric particulate matter contributes negligibly to HF uptake. Finally, given that the reactivity of HF at a high release rate and elevated mole concentration cannot be ignored, it is important to incorporate the reaction chemistry in the near-field dispersion close to the proximity of the release source, and to incorporate the deposition mechanism in the far-field dispersion away from the release source. In other words, a hybrid computational scheme may be needed to address transport and atmospheric chemistry of HF in a range of applications. The model uncertainty will be limited by the precision of boundary layer parameterization and ability to accurately model the atmospheric turbulence.« less

Authors:
ORCiD logo [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1351771
Alternate Identifier(s):
OSTI ID: 1399939
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Atmospheric Chemistry
Additional Journal Information:
Journal Volume: 2017; Journal ID: ISSN 0167-7764
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 54 ENVIRONMENTAL SCIENCES; HF; hazard; dispersion; dense gas; transport

Citation Formats

Cheng, Meng -Dawn. Atmospheric chemistry of hydrogen fluoride. United States: N. p., 2017. Web. doi:10.1007/s10874-017-9359-7.
Cheng, Meng -Dawn. Atmospheric chemistry of hydrogen fluoride. United States. doi:10.1007/s10874-017-9359-7.
Cheng, Meng -Dawn. Tue . "Atmospheric chemistry of hydrogen fluoride". United States. doi:10.1007/s10874-017-9359-7. https://www.osti.gov/servlets/purl/1351771.
@article{osti_1351771,
title = {Atmospheric chemistry of hydrogen fluoride},
author = {Cheng, Meng -Dawn},
abstractNote = {In this study, the atmospheric chemistry, emissions, and surface boundary layer transport of hydrogen fluoride (HF) is summarized. Although HF is known to be chemically reactive and highly soluble, both factors affect transport and removal in the atmosphere, we suggest that the chemistry can be ignored when the HF concentration is at a sufficiently low level (e.g., 10 ppmv). At a low concentration, the capability for HF to react in the atmosphere is diminished and therefore the species can be mathematically treated as inert during the transport. At a sufficiently high concentration of HF (e.g., kg/s release rate and thousands of ppm), however, HF can go through a series of rigorous chemical reactions including polymerization, depolymerization, and reaction with water to form molecular complex. As such, the HF species cannot be considered as inert because the reactions could intimately influence the plume s thermodynamic properties affecting the changes in plume temperature and density. The atmospheric residence time of HF was found to be less than four (4) days, and deposition (i.e., atmosphere to surface transport) is the dominant mechanism that controls the removal of HF and its oligomers from the atmosphere. The literature data on HF dry deposition velocity was relatively high compared to many commonly found atmospheric species such as ozone, sulfur dioxide, nitrogen oxides, etc. The global average of wet deposition velocity of HF was found to be zero based on one literature source. Uptake of HF by rain drops is limited by the acidity of the rain drops, and atmospheric particulate matter contributes negligibly to HF uptake. Finally, given that the reactivity of HF at a high release rate and elevated mole concentration cannot be ignored, it is important to incorporate the reaction chemistry in the near-field dispersion close to the proximity of the release source, and to incorporate the deposition mechanism in the far-field dispersion away from the release source. In other words, a hybrid computational scheme may be needed to address transport and atmospheric chemistry of HF in a range of applications. The model uncertainty will be limited by the precision of boundary layer parameterization and ability to accurately model the atmospheric turbulence.},
doi = {10.1007/s10874-017-9359-7},
journal = {Journal of Atmospheric Chemistry},
number = ,
volume = 2017,
place = {United States},
year = {Tue Apr 11 00:00:00 EDT 2017},
month = {Tue Apr 11 00:00:00 EDT 2017}
}

Journal Article:
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  • The gas-phase ion chemistry of HF is investigated using the techniques of ion cyclotron resonance spectroscopy. The only observed reaction of the parent ion is HF/sup +/ + HF ..-->.. H/sub 2/F/sup +/ + F for which a bimolecular rate constant k = (9 +- 3) x 10/sup -10/ cm/sup 3/ molecule/sup -1/ sec/sup -1/ is determined. Proton-transfer reactions in mixtures of HF with N/sub 2/, CH/sub 4/, and CO/sub 2/ are examined to determine the proton affinity of HF. While HF is found to be substantially less basic than CH/sub 4/ and CO/sub 2/, the proton affinities of HFmore » and N/sub 2/ are comparable. From the measured equilibrium constant and estimated entropy change a value of ..delta..H = 1.1 +- 0.2 kcal/mol is calculated for the reaction H/sub 2/F/sup +/ + N/sub 2/ reversible N/sub 2/H/sup +/ + HF. From previous studies of PA(N/sub 2/) this allows an absolute value of PA(HF) = 112 +- 2 kcal/mol to be determined. The disparate base strength of HF relative to the other hydrogen halides is discussed. 23 references, 2 figures, 1 table.« less
  • The gas-phase ion chemistry of HF is investigated using the techniques of ion cyclotron resonance spectroscopy. The only observed reaction of the parent ion is HF/sup +/ + HF ..-->.. H/sub 2/F/sup +/ + F for which a biomolecular rate constant k = (9 +- 3) x 10/sup -10/ cm/sup 3/ molecule/sup -1/ sec/sup -1/ is determined. Proton-transfer reactions in mixtures of HF with N/sub 2/, CH/sub 4/, and CO/sub 2/ are examined to determine the proton affinity of HF. While HF is found to be substantially less basic than CH/sub 4/ and CO/sub 2/, the proton affinities of HFmore » and N/sub 2/ are comparable. From the measured equilibrium constant and estimated entropy change a value of ..delta..H = -1.1 +- 0.2 kcal/mole is calculated for the reaction H/sub 2/F/sup +/ + N/sub 2/ reverse arrows N/sub 2/H/sup +/ + HF. From previous studies of PA(N/sub 2/) this allows an absolute value of PA(HF) = 112 +- 2 kcal/mole to be determined. The disparate base strength of HF relative to the other hydrogen halides is discussed.« less
  • Isothermal vapor-liquid equilibria for the three binary systems (1-chloro-1,1-difluoroethane + hydrogen fluoride, 1,1-dichloro-1-fluoroethane + hydrogen fluoride, and chlorodifluoromethane + hydrogen fluoride) have been measured. The experimental data for the binary systems are correlated with the NRTL equation with the vapor-phase association model for the mixtures containing hydrogen fluoride, and the relevant parameters are presented. All of the systems form minimum boiling heterogeneous azeotropes.
  • Isothermal vapor-liquid equilibria for difluoromethane + hydrogen fluoride, dichlorodifluoromethane + hydrogen fluoride, and chlorine + hydrogen fluoride have been measured. The experimental data for the binary systems are correlated with the NRTL equation with the vapor-phase association model for the mixtures containing hydrogen fluoride, and the relevant parameters are presented. The binary system difluoromethane + hydrogen fluoride forms a homogeneous liquid phase, and the others form minimum boiling heterogeneous azeotropes at the experimental conditions.