Partitioning of oxygen isotopes during the aqueous solvation of nitric acid
Abstract
Mixtures of water and inorganic acids show differences in isotopic composition between the vapor and liquid phases, reportedly even at an azeotrope. A recent reactive azeotropy analysis rationalized this by allowing for differences in stable isotope composition between bound solvation complexes and the bulk liquid. In this study, a mixture of water and nitric acid was examined experimentally to determine whether or not significant differences in stable isotope composition exist between bound solvation complexes and the bulk solution. A Rayleigh distillation was conducted using a solution of nitric acid and water. During the distillation, it was expected that bulk water would be vaporized first while (bound) water involved with hydrating the acid would be vaporized at later times along with the acid. Samples of both distillate and residual liquid were collected over time intervals and analyzed to determine oxygen and nitrogen stable isotope composition using isotope ratio mass spectrometry. Comparative samples were collected from the distillation of water alone. The measured oxygen fractionation factors suggest that the acid is preferentially hydrated with 18O-enriched water, compared to the unbound, or bulk, water. Preferential coordination of 18O-enriched water with the dissolved acid is consistent with heavier water forming stronger bonds relative tomore »
- Authors:
-
[2];
[2];
[2];
[2];
[2]
- Univ. of Texas at Austin, Austin, TX (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (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:
- 1572331
- Alternate Identifier(s):
- OSTI ID: 1703648
- Report Number(s):
- LA-UR-19-25191
Journal ID: ISSN 0378-3812
- Grant/Contract Number:
- 89233218CNA000001; 20180066DR
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Fluid Phase Equilibria
- Additional Journal Information:
- Journal Volume: 506; Journal ID: ISSN 0378-3812
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; oxygen isotopes; Nitric acid-water; Stable isotope fractionation
Citation Formats
Larson, Toti E., Perkins, George B., Williams, Robert F., Fessenden, Julianna E., Clegg, Samuel M., and Currier, Robert P. Partitioning of oxygen isotopes during the aqueous solvation of nitric acid. United States: N. p., 2019.
Web. doi:10.1016/j.fluid.2019.112364.
Larson, Toti E., Perkins, George B., Williams, Robert F., Fessenden, Julianna E., Clegg, Samuel M., & Currier, Robert P. Partitioning of oxygen isotopes during the aqueous solvation of nitric acid. United States. https://doi.org/10.1016/j.fluid.2019.112364
Larson, Toti E., Perkins, George B., Williams, Robert F., Fessenden, Julianna E., Clegg, Samuel M., and Currier, Robert P. Thu .
"Partitioning of oxygen isotopes during the aqueous solvation of nitric acid". United States. https://doi.org/10.1016/j.fluid.2019.112364. https://www.osti.gov/servlets/purl/1572331.
@article{osti_1572331,
title = {Partitioning of oxygen isotopes during the aqueous solvation of nitric acid},
author = {Larson, Toti E. and Perkins, George B. and Williams, Robert F. and Fessenden, Julianna E. and Clegg, Samuel M. and Currier, Robert P.},
abstractNote = {Mixtures of water and inorganic acids show differences in isotopic composition between the vapor and liquid phases, reportedly even at an azeotrope. A recent reactive azeotropy analysis rationalized this by allowing for differences in stable isotope composition between bound solvation complexes and the bulk liquid. In this study, a mixture of water and nitric acid was examined experimentally to determine whether or not significant differences in stable isotope composition exist between bound solvation complexes and the bulk solution. A Rayleigh distillation was conducted using a solution of nitric acid and water. During the distillation, it was expected that bulk water would be vaporized first while (bound) water involved with hydrating the acid would be vaporized at later times along with the acid. Samples of both distillate and residual liquid were collected over time intervals and analyzed to determine oxygen and nitrogen stable isotope composition using isotope ratio mass spectrometry. Comparative samples were collected from the distillation of water alone. The measured oxygen fractionation factors suggest that the acid is preferentially hydrated with 18O-enriched water, compared to the unbound, or bulk, water. Preferential coordination of 18O-enriched water with the dissolved acid is consistent with heavier water forming stronger bonds relative to light water. Here, the results imply that isotope-dependent partitioning between bulk solvent and dissolved complexes may prove necessary in developing accurate descriptions of isotope fractionation during vapor-liquid equilibrium.},
doi = {10.1016/j.fluid.2019.112364},
journal = {Fluid Phase Equilibria},
number = ,
volume = 506,
place = {United States},
year = {2019},
month = {10}
}
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Figure 1: Measured δ18O values in the still pot (open circles) and in the distillate (closed circles) as a function of fraction liquid phase remaining. To provide a visual aid, the data were least squares fit to a Rayleigh equation that is shown on the plot as a solid line.
Figures / Tables found in this record: