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

Abstract

Large complex formation involved in the thermal decomposition of hydrazine (N2H4) is studied 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//omega B97x-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 forms N2H3 + N2H3, while disproportionation of N2H3 + N2H3 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 because of 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.

Authors:
; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science - Office of Basic Energy Sciences - Chemical Sciences, Geosciences, and Biosciences Division; US Army Research Office (ARO)
OSTI Identifier:
1531171
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
Additional Journal Information:
Journal Volume: 123; Journal Issue: 22
Country of Publication:
United States
Language:
English

Citation Formats

Grinberg Dana, Alon, Moore, III, Kevin B., Jasper, Ahren W., and Green, William H. Large Intermediates in Hydrazine Decomposition: A Theoretical Study of the N{sub 3}H{sub 5} and N{sub 4}H{sub 6} Potential Energy Surfaces. United States: N. p., 2019. Web. doi:10.1021/acs.jpca.9b02217.
Grinberg Dana, Alon, Moore, III, Kevin B., Jasper, Ahren W., & Green, William H. Large Intermediates in Hydrazine Decomposition: A Theoretical Study of the N{sub 3}H{sub 5} and N{sub 4}H{sub 6} Potential Energy Surfaces. United States. doi:10.1021/acs.jpca.9b02217.
Grinberg Dana, Alon, Moore, III, Kevin B., Jasper, Ahren W., and Green, William H. Thu . "Large Intermediates in Hydrazine Decomposition: A Theoretical Study of the N{sub 3}H{sub 5} and N{sub 4}H{sub 6} Potential Energy Surfaces". United States. doi:10.1021/acs.jpca.9b02217.
@article{osti_1531171,
title = {Large Intermediates in Hydrazine Decomposition: A Theoretical Study of the N{sub 3}H{sub 5} and N{sub 4}H{sub 6} Potential Energy Surfaces},
author = {Grinberg Dana, Alon and Moore, III, Kevin B. and Jasper, Ahren W. and Green, William H.},
abstractNote = {Large complex formation involved in the thermal decomposition of hydrazine (N2H4) is studied 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//omega B97x-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 forms N2H3 + N2H3, while disproportionation of N2H3 + N2H3 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 because of 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 = 22,
volume = 123,
place = {United States},
year = {2019},
month = {6}
}