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Title: Azeotropic isotopologues

Abstract

Isotopologues are molecular species differing only in their stable isotope composition. For example, the isotopologues of water include HOH, DOD, and HOD. The possibility of reactive azeotropy among isotopologues of the same molecule is explored within the ideal gas/ideal solution assumption. The chemical equilibrium enabling azeotropy may involve isotope exchange reactions or may involve more complicated dissociation/solvation chemistry. Azeotropy among isotopologues appears possible in the presence of isotope exchange reactions and with simple dissociation or combination reactions. However, for such chemical reactions, the isotope fractionation factors must be unity, that is, isotope ratios are identical in the vapor and liquid phases. This is not consistent with experimental observations that isotope fractionation factors can differ from unity at an azeotrope. More complex solvation chemistry, wherein the isotopic composition in the solvation shell differs slightly from that of the bulk solvent, can lead to an azeotrope for which the isotope fractionation factor is not unity. Possible azeotropy among the isotopologues of water is then considered. Experiments to directly quantify water isotopologue compositions at the elevated temperatures and pressures anticipated for azeotropy are described. Furthermore the paper concludes with a discussion of the potential impact of azotropic isotopologues on the azeotropic extraction andmore » isotopic analysis of soil water and on the interpretation of isotopic signatures in geological and cosmological samples.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2]; ORCiD logo [1]; ORCiD logo [1];  [3]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Tulane Univ., New Orleans, LA (United States)
  3. Univ. of Texas at Austin, Austin, TX (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1508558
Report Number(s):
LA-UR-18-30223
Journal ID: ISSN 0378-3812
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Accepted Manuscript
Journal Name:
Fluid Phase Equilibria
Additional Journal Information:
Journal Name: Fluid Phase Equilibria; Journal ID: ISSN 0378-3812
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; isotopologues; azeotropy; stable isotopes

Citation Formats

Currier, Robert P., Peery, Travis B., Herman, Michael F., Williams, Robert F., Michalczyk, Ryszard, Larson, Toti E., Labotka, Dana Miller, Fessenden, Julianna Eileen, and Clegg, Samuel M. Azeotropic isotopologues. United States: N. p., 2019. Web. doi:10.1016/j.fluid.2019.04.006.
Currier, Robert P., Peery, Travis B., Herman, Michael F., Williams, Robert F., Michalczyk, Ryszard, Larson, Toti E., Labotka, Dana Miller, Fessenden, Julianna Eileen, & Clegg, Samuel M. Azeotropic isotopologues. United States. doi:10.1016/j.fluid.2019.04.006.
Currier, Robert P., Peery, Travis B., Herman, Michael F., Williams, Robert F., Michalczyk, Ryszard, Larson, Toti E., Labotka, Dana Miller, Fessenden, Julianna Eileen, and Clegg, Samuel M. Thu . "Azeotropic isotopologues". United States. doi:10.1016/j.fluid.2019.04.006.
@article{osti_1508558,
title = {Azeotropic isotopologues},
author = {Currier, Robert P. and Peery, Travis B. and Herman, Michael F. and Williams, Robert F. and Michalczyk, Ryszard and Larson, Toti E. and Labotka, Dana Miller and Fessenden, Julianna Eileen and Clegg, Samuel M.},
abstractNote = {Isotopologues are molecular species differing only in their stable isotope composition. For example, the isotopologues of water include HOH, DOD, and HOD. The possibility of reactive azeotropy among isotopologues of the same molecule is explored within the ideal gas/ideal solution assumption. The chemical equilibrium enabling azeotropy may involve isotope exchange reactions or may involve more complicated dissociation/solvation chemistry. Azeotropy among isotopologues appears possible in the presence of isotope exchange reactions and with simple dissociation or combination reactions. However, for such chemical reactions, the isotope fractionation factors must be unity, that is, isotope ratios are identical in the vapor and liquid phases. This is not consistent with experimental observations that isotope fractionation factors can differ from unity at an azeotrope. More complex solvation chemistry, wherein the isotopic composition in the solvation shell differs slightly from that of the bulk solvent, can lead to an azeotrope for which the isotope fractionation factor is not unity. Possible azeotropy among the isotopologues of water is then considered. Experiments to directly quantify water isotopologue compositions at the elevated temperatures and pressures anticipated for azeotropy are described. Furthermore the paper concludes with a discussion of the potential impact of azotropic isotopologues on the azeotropic extraction and isotopic analysis of soil water and on the interpretation of isotopic signatures in geological and cosmological samples.},
doi = {10.1016/j.fluid.2019.04.006},
journal = {Fluid Phase Equilibria},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {4}
}

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This content will become publicly available on April 11, 2020
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