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Title: Large Intermediates in Hydrazine Decomposition: A Theoretical Study of the N 3H 5 and N 4H 6 Potential Energy Surfaces

Abstract

Large complex formation involved in the thermal decomposition of hydrazine (N 2H 4) is studied here using transition state theory based theoretical kinetics. A comprehensive analysis of the N 3H 5 and N 4H 6 potential energy surfaces was performed at the CCSD(T)-F12a/aug-cc-pVTZ//ωB97x-D3/6-311++G(3df,3pd) level of theory, and pressure-dependent rate coefficients were determined. There are no low-barrier unimolecular decomposition pathways for triazane (n-N 3H 5), and its formation becomes more significant as the pressure increases; it is the primary product of N 2H 3 + NH 2 below 550, 800, 1150, and 1600 K at 0.1, 1, 10, and 100 bar, respectively. The N 4H 6 surface has two important entry channels, N 2H 4 + H 2NN and N 2H 3 + N 2H 3, each with different primary products. Interestingly, N 2H 4 + H 2NN primarily form N 2H 3 + N 2H 3, while disproportionation of N 2H 3 + N 3H 3 predominantly leads to the other N 2H 2 isomer, HNNH. Stabilized tetrazane (n-N 4H 6) formation from N 2H 3 + N 2H 3 becomes significant only at relatively high pressures and low temperatures due to fall-off back into N 2H 3 + Nmore » 2H 3. Pressure-dependent rate coefficients for all considered reactions as well as thermodynamic properties of triazane and tetrazane, which should be considered for kinetic modeling of chemical processes involving nitrogen- and hydrogen-containing species, are reported.« less

Authors:
 [1];  [2];  [2];  [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Chemical Engineering
  2. Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division
Publication Date:
Research Org.:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); US Army Research Office (ARO)
OSTI Identifier:
1510335
Grant/Contract Number:  
SC0014901; W911NF1710531
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
Additional Journal Information:
Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory; Journal ID: ISSN 1089-5639
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Grinberg Dana, Alon, Moore, Kevin Bruce, Jasper, Ahren Ward, and Green, William H. Large Intermediates in Hydrazine Decomposition: A Theoretical Study of the N3H5 and N4H6 Potential Energy Surfaces. United States: N. p., 2019. Web. doi:10.1021/acs.jpca.9b02217.
Grinberg Dana, Alon, Moore, Kevin Bruce, Jasper, Ahren Ward, & Green, William H. Large Intermediates in Hydrazine Decomposition: A Theoretical Study of the N3H5 and N4H6 Potential Energy Surfaces. United States. doi:10.1021/acs.jpca.9b02217.
Grinberg Dana, Alon, Moore, Kevin Bruce, Jasper, Ahren Ward, and Green, William H. Thu . "Large Intermediates in Hydrazine Decomposition: A Theoretical Study of the N3H5 and N4H6 Potential Energy Surfaces". United States. doi:10.1021/acs.jpca.9b02217.
@article{osti_1510335,
title = {Large Intermediates in Hydrazine Decomposition: A Theoretical Study of the N3H5 and N4H6 Potential Energy Surfaces},
author = {Grinberg Dana, Alon and Moore, Kevin Bruce and Jasper, Ahren Ward and Green, William H.},
abstractNote = {Large complex formation involved in the thermal decomposition of hydrazine (N2H4) is studied here using transition state theory based theoretical kinetics. A comprehensive analysis of the N3H5 and N4H6 potential energy surfaces was performed at the CCSD(T)-F12a/aug-cc-pVTZ//ωB97x-D3/6-311++G(3df,3pd) level of theory, and pressure-dependent rate coefficients were determined. There are no low-barrier unimolecular decomposition pathways for triazane (n-N3H5), and its formation becomes more significant as the pressure increases; it is the primary product of N2H3 + NH2 below 550, 800, 1150, and 1600 K at 0.1, 1, 10, and 100 bar, respectively. The N4H6 surface has two important entry channels, N2H4 + H2NN and N2H3 + N2H3, each with different primary products. Interestingly, N2H4 + H2NN primarily form N2H3 + N2H3, while disproportionation of N2H3 + N3H3 predominantly leads to the other N2H2 isomer, HNNH. Stabilized tetrazane (n-N4H6) formation from N2H3 + N2H3 becomes significant only at relatively high pressures and low temperatures due to fall-off back into N2H3 + N2H3. Pressure-dependent rate coefficients for all considered reactions as well as thermodynamic properties of triazane and tetrazane, which should be considered for kinetic modeling of chemical processes involving nitrogen- and hydrogen-containing species, are reported.},
doi = {10.1021/acs.jpca.9b02217},
journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {5}
}

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This content will become publicly available on May 2, 2020
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