Ab initio calculations of the polymerization pathways of isocyanic acid HNCO

Geith, Janna; Klapötke, Thomas M.

doi:10.1016/s0166-1280(00)00637-0

Cited by 22 publications

(14 citation statements)

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“…70 (10) Gas-phase detection of HNCO in our drop-test experiments would suggest that the observed CO 2 /N 2 O signal represents a ratio less than 2/3 during the preignition phase and that possibly further reactions of HNCO and/or other vapors from DNB decomposition lead to the gas-phase ignition of the IL fuels and salts studied here as seen in Figure 2c. 67,71 The difference spectrum in Figure 6 shows the infrared spectrum of HNCO formed in the reaction of WFNA with 1-butyl-3-methylimidazolium dicyanamide, Figure 8 shows product spectrum for WFNA with sodium dicyanamide, and Figure 10 shows the difference spectrum when silver cyanate (AgOCN) is reacted with WFNA. The ratio of intensities of CO 2 /N 2 O in Figure 10 is different from that in Figure 8 indicating a different reaction stoichiometry than for the dicyanamides, with less N 2 O formation since its source can only be from hydrolysis of HNCO formed in the exothermic condensed phase reaction of AgOCN with nitric acid.…”

Section: Cautionmentioning

confidence: 99%

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

et al. 2008

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)Air Force Research Laboratory (AFMC) AFRL/RZS SPONSOR/MONITOR'S Pollux Drive NUMBER(S)Edwards AFB CA 93524-70448 AFRL-RZ-ED-JA-2008-090 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution unlimited (PA# 08149A) SUPPLEMENTARY NOTESPublished in J. Phys. Chem. A 2008, 112, 7816-7824. © 2008 American Chemical Society. ABSTRACTA class of room temperature ionic liquids (RTILs) that exhibit hypergolic activity towards strong nitric acid is reported. Fast ignition of dicyanamide ionic liquids when mixed with nitric acid is contrasted with the reactivity of the ionic liquid azides, which show high reactivity with nitric acid, but do not ignite. The reactivity of other potential salt fuels is assessed here. Rapid-scan, Fourier Transform infrared (FTIR) spectroscopy of the pre-ignition phase indicates the evolution of N 2 O from both the dicyanamide and azide RTILs. Evidence for the evolution of CO 2 and isocyanic acid (HNCO) with similar temporal behavior to N 2 O from reaction of the dicyanamide ionic liquids with nitric acid is presented. Evolution of HN 3 is detected from the azides. No evolution of HCN from the dicyanamide reactions was detected. From the FTIR observations, biuret reaction tests and initial ab initio calculations, a mechanism is proposed for the formation of N 2 O, CO 2 and HNCO from the dicyanamide reactions during pre-ignition. SUBJECT TERMS SECURITY CLASSIFICATION OF:17 ReceiVed: April 28, 2008; ReVised Manuscript ReceiVed: June 2, 2008 A class of room-temperature ionic liquids (RTILs) that exhibit hypergolic activity toward fuming nitric acid is reported. Fast ignition of dicyanamide ionic liquids when mixed with nitric acid is contrasted with the reactivity of the ionic liquid azides, which show high reactivity with nitric acid, but do not ignite. The reactivity of other potential salt fuels is assessed here. Rapid-scan, Fourier transform infrared (FTIR) spectroscopy of the preignition phase indicates the evolution of N 2 O from both the dicyanamide and azide...

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Section: Cautionmentioning

confidence: 99%

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

et al. 2008

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“…In view of the theoretical investigation of the polymerization pathways of isocyanic acid we have performed semi-empirical (PM3/VSTO-3G(d) method) and ab initio HF and MP2 calculations employing the 6-31G(d,p) basis set [16]. It was found that the polymerization of HNCO to oxo (keto) cyanuric acid is thermodynamically the most favorable.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Properties and Dimerization Study of Isocyanic Acid

Fischer

Geith

Klapötke

et al. 2002

Zeitschrift Für Naturforschung B

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Isocyanic Acid, Dimeric Isocyanic Acid Isocyanic acid was prepared in pure form by reaction of KOCN or NaOCN with stearic or oxalic acid in good yield. Identification, characterization and investigation of the thermal stability of HNCO and evidence for a possible existence of "dicyanic acid" have been studied in gas phase, liquid and solid state by vibrational and NMR spectroscopy and mass spectrometry.

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“…[1][2][3] In recent years, many experimental investigations on HNCO have been performed. [4][5][6][7][8][9][10][11][12][13][14][15] Some studies have reported the photolysis reactions [4][5][6][7][8] and the polymerization pathways of HNCO.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of the Reaction Mechanism for SiF₂Radical with HNCO

Hou¹,

Wu²,

Kong³

et al. 2013

Bulletin of the Korean Chemical Society

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The reaction mechanism of SiF2 radical with HNCO has been investigated by the B3LYP method of density functional theory(DFT), while the geometries and harmonic vibration frequencies of reactants, intermediates, transition states and products have been calculated at the B3LYP/6-311++G** level. To obtain more precise energy result, stationary point energies were calculated at the CCSD(T)/6-311++G**//B3LYP/6-311++G** level. SiF2+HNCO→IM3→TS5→IM4→TS6→OSiF2CNH(P3) was the main channel with low potential energy, OSiF2CNH was the main product. The analyses for the combining interaction between SiF2 radical and HNCO with the atom-in-molecules theory (AIM) have been performed.

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Ab initio calculations of the polymerization pathways of isocyanic acid HNCO

Cited by 22 publications

References 19 publications

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

Synthesis, Properties and Dimerization Study of Isocyanic Acid

Theoretical Study of the Reaction Mechanism for SiF₂Radical with HNCO

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Ab initio calculations of the polymerization pathways of isocyanic acid HNCO

Cited by 22 publications

References 19 publications

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

Fourier Transform Infrared Studies in Hypergolic Ignition of Ionic Liquids

Synthesis, Properties and Dimerization Study of Isocyanic Acid

Theoretical Study of the Reaction Mechanism for SiF2Radical with HNCO

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Product

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Theoretical Study of the Reaction Mechanism for SiF₂Radical with HNCO