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Title: Thermal Dissociation of Alkyl Nitrates and Recombination of Alkyl Radicals

Abstract

The thermal dissociations of three alkyl nitrites (C3H7ONO, n-C4H9ONO, and i-C4H9ONO) have been studied in a diaphragmless shock tube by laser schlieren densitometry over 700 < T < 1000 K and 60 < P <250 Torr. The nitrites act as clean, thermal sources of alkyl radicals that create the radicals at much lower temperatures than are accessible with other precursors. The decomposition of the three nitrites proceeds via a common mechanism, which is discussed. Rate coefficients for dissociation of the alkyl nitrites to an alkoxy radical and NO, k(1), were obtained with an uncertainty of 30%. Rice-Ramsperger-Kassel-Marcus/Master Equation (RRKM/ME) calculations for dissociation of the nitrites were performed and provide excellent simulations of the experimental results. The high-pressure limit rate coefficients from the RRKM/ME calculations are: k(1,C3H7ONO) = (5.69 +/- 1.71) x 10(21)T(-1.60) exp(-21458/T) s(-1) ; k(1),n-C4H9ONO = (9.91 +/- 2.97) x 10(21)T(-1.59)exp(-21588 /T)s(-1) ; k(1)(,i)-C4H9ONO = (3.92 +/- 1.18) x 10(21)T(-1.)(58)exp(-21162/T)s(-1) . At the low temperatures of this work, the alkyl radicals are thermally stable and thus their recombination reactions were also studied. The recombination rate coefficients for ethyl, n-propyl and i-propyl radicals (uncertainties of 50%) are in excellent agreement with literature values, particularly recent theoretical results, and extend themore » range of experiments to higher temperatures. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.« less

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
OSTI Identifier:
1513218
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Conference: 37th International Symposium on Combustion, 07/29/18 - 08/03/18, Dublin, IE
Country of Publication:
United States
Language:
English
Subject:
nitrite; radical recombination; radical source; shock tube

Citation Formats

Randazzo, John B., Fuller, Mark E., Goldsmith, C. Franklin, and Tranter, Robert S. Thermal Dissociation of Alkyl Nitrates and Recombination of Alkyl Radicals. United States: N. p., 2019. Web. doi:10.1016/j.proci.2018.05.085.
Randazzo, John B., Fuller, Mark E., Goldsmith, C. Franklin, & Tranter, Robert S. Thermal Dissociation of Alkyl Nitrates and Recombination of Alkyl Radicals. United States. doi:10.1016/j.proci.2018.05.085.
Randazzo, John B., Fuller, Mark E., Goldsmith, C. Franklin, and Tranter, Robert S. Tue . "Thermal Dissociation of Alkyl Nitrates and Recombination of Alkyl Radicals". United States. doi:10.1016/j.proci.2018.05.085.
@article{osti_1513218,
title = {Thermal Dissociation of Alkyl Nitrates and Recombination of Alkyl Radicals},
author = {Randazzo, John B. and Fuller, Mark E. and Goldsmith, C. Franklin and Tranter, Robert S.},
abstractNote = {The thermal dissociations of three alkyl nitrites (C3H7ONO, n-C4H9ONO, and i-C4H9ONO) have been studied in a diaphragmless shock tube by laser schlieren densitometry over 700 < T < 1000 K and 60 < P <250 Torr. The nitrites act as clean, thermal sources of alkyl radicals that create the radicals at much lower temperatures than are accessible with other precursors. The decomposition of the three nitrites proceeds via a common mechanism, which is discussed. Rate coefficients for dissociation of the alkyl nitrites to an alkoxy radical and NO, k(1), were obtained with an uncertainty of 30%. Rice-Ramsperger-Kassel-Marcus/Master Equation (RRKM/ME) calculations for dissociation of the nitrites were performed and provide excellent simulations of the experimental results. The high-pressure limit rate coefficients from the RRKM/ME calculations are: k(1,C3H7ONO) = (5.69 +/- 1.71) x 10(21)T(-1.60) exp(-21458/T) s(-1) ; k(1),n-C4H9ONO = (9.91 +/- 2.97) x 10(21)T(-1.59)exp(-21588 /T)s(-1) ; k(1)(,i)-C4H9ONO = (3.92 +/- 1.18) x 10(21)T(-1.)(58)exp(-21162/T)s(-1) . At the low temperatures of this work, the alkyl radicals are thermally stable and thus their recombination reactions were also studied. The recombination rate coefficients for ethyl, n-propyl and i-propyl radicals (uncertainties of 50%) are in excellent agreement with literature values, particularly recent theoretical results, and extend the range of experiments to higher temperatures. (C) 2018 The Combustion Institute. Published by Elsevier Inc. All rights reserved.},
doi = {10.1016/j.proci.2018.05.085},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {1}
}

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