Sensitive Mass Spectrometer for Time-Resolved Gas-Phase Chemistry Studies at High Pressures

doi:10.1021/acs.jpca.9b08393

Title: Sensitive Mass Spectrometer for Time-Resolved Gas-Phase Chemistry Studies at High Pressures

Full Record
Other Related Research

Abstract

Here, we report the construction of a new experimental apparatus for direct time-resolved probing of high-pressure gas-phase chemical reactions by photoionization mass spectrometry. The apparatus uses a laser photolysis slow-flow reactor, capable of operating at P = 0.3 — 100 bar and T = 300 — 1000 K. In this report, we initiate reactions in homogeneous gas mixtures by the photolysis of appropriate radical precursor using laser pulses at repetition rates of 1 — 10 Hz. The reacting mixture is continuously sampled into a vacuum chamber, ionized by VUV photons from laboratory-based discharge lamps or from a synchrotron beamline, and analyzed by a custom-designed mass spectrometer. Soft near-threshold ionization by tunable synchrotron radiation enables spectroscopic quantification of many key intermediates and products of chemical reactions. A novel ionization scheme in the high-density region of the sample gas jet increases the experimental sensitivity 100-fold, compared with existing instruments, without compromising mass resolution. A 40-kHz pulsed reflectron time-of-flight mass spectrometer in the orthogonal acceleration geometry achieves simultaneous detection of all ionized species with 25-μs time resolution. We show the power of this apparatus by investigating the ethyl radical oxidation reaction using very dilute (<10¹² molecules • cm^-3) ethyl concentrations at pressures upmore » to 25 bar.« less

Authors:

^[1]; Antonov, Ivan ^[1]; Au, Kendrew ^[1]

Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Publication Date:: 2019-11-11

Research Org.:: Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division

OSTI Identifier:: 1574695

Report Number(s):: SAND-2019-10135J
Journal ID: ISSN 1089-5639; 678901; TRN: US2001320

Grant/Contract Number:: AC04-94AL85000; NA0003525; AC02-05CH11231

Resource Type:: Accepted Manuscript

Journal Name:: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Additional Journal Information:: Journal Volume: 123; Journal Issue: 50; Journal ID: ISSN 1089-5639

Publisher:: American Chemical Society

Country of Publication:: United States

Language:: English

Subject:: 47 OTHER INSTRUMENTATION

Citation Formats


                    Sheps, Leonid, Antonov, Ivan, and Au, Kendrew. Sensitive Mass Spectrometer for Time-Resolved Gas-Phase Chemistry Studies at High Pressures.  United States: N. p., 2019. 
        Web.  doi:10.1021/acs.jpca.9b08393.

Copy to clipboard


                    Sheps, Leonid, Antonov, Ivan, & Au, Kendrew. Sensitive Mass Spectrometer for Time-Resolved Gas-Phase Chemistry Studies at High Pressures.  United States.  doi:10.1021/acs.jpca.9b08393.

Copy to clipboard


                    Sheps, Leonid, Antonov, Ivan, and Au, Kendrew. Mon .  
        "Sensitive Mass Spectrometer for Time-Resolved Gas-Phase Chemistry Studies at High Pressures".  United States.  doi:10.1021/acs.jpca.9b08393.  https://www.osti.gov/servlets/purl/1574695.

Copy to clipboard


                    
@article{osti_1574695,

  title        = {Sensitive Mass Spectrometer for Time-Resolved Gas-Phase Chemistry Studies at High Pressures},

  author       = {Sheps, Leonid and Antonov, Ivan and Au, Kendrew},

  abstractNote = {Here, we report the construction of a new experimental apparatus for direct time-resolved probing of high-pressure gas-phase chemical reactions by photoionization mass spectrometry. The apparatus uses a laser photolysis slow-flow reactor, capable of operating at P = 0.3 — 100 bar and T = 300 — 1000 K. In this report, we initiate reactions in homogeneous gas mixtures by the photolysis of appropriate radical precursor using laser pulses at repetition rates of 1 — 10 Hz. The reacting mixture is continuously sampled into a vacuum chamber, ionized by VUV photons from laboratory-based discharge lamps or from a synchrotron beamline, and analyzed by a custom-designed mass spectrometer. Soft near-threshold ionization by tunable synchrotron radiation enables spectroscopic quantification of many key intermediates and products of chemical reactions. A novel ionization scheme in the high-density region of the sample gas jet increases the experimental sensitivity 100-fold, compared with existing instruments, without compromising mass resolution. A 40-kHz pulsed reflectron time-of-flight mass spectrometer in the orthogonal acceleration geometry achieves simultaneous detection of all ionized species with 25-μs time resolution. We show the power of this apparatus by investigating the ethyl radical oxidation reaction using very dilute (<1012 molecules • cm-3) ethyl concentrations at pressures up to 25 bar.},

  doi          = {10.1021/acs.jpca.9b08393},

  journal      = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},

  number       = 50,

  volume       = 123,

  place        = {United States},

  year         = {2019},

  month        = {11}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

DOI: 10.1021/acs.jpca.9b08393

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 2 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Similar Records in DOE PAGES and OSTI.GOV collections:

Single- and multi-photon ionization studies of organosulfur species

Thesis/Dissertation Cheung, Yu -San

Accurate ionization energies (IE`s) for molecular species are used for prediction of chemical reactivity and are of fundamental importance to chemists. The IE of a gaseous molecule can be determined routinely in a photoionization or a photoelectron experiment. IE determinations made in conventional photoionization and photoelectron studies have uncertainties in the range of 3--100 meV (25--250 cm^-1). In the past decade, the most exciting development in the field of photoionization and photoelectron spectroscopy has been the availability of high resolution, tunable ultraviolet (UV) and vacuum ultraviolet (VUV) laser sources. The laser pulsed field ionization photoelectron (PFI-PE) scheme is currently themore »« less
DOI: 10.2172/350831

Full Text Available
Combined Experimental and Computational Study on the Unimolecular Decomposition of JP-8 Jet Fuel Surrogates. I. n-Decane (n-C₁₀H₂₂)

Journal Article Zhao, Long ; Yang, Tao ; Kaiser, Ralf I. ; ... - Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Exploiting a high temperature chemical reactor, we explored in this paper the pyrolysis of helium-seeded n-decane as a surrogate of the n-alkane fraction of Jet Propellant-8 (JP-8) over a temperature range of 1100–1600 K at a pressure of 600 Torr. The nascent products were identified in situ in a supersonic molecular beam via single photon vacuum ultraviolet (VUV) photoionization coupled with a mass spectroscopic analysis of the ions in a reflectron time-of-flight mass spectrometer (ReTOF). Our studies probe, for the first time, the initial reaction products formed in the decomposition of n-decane—including radicals and thermally labile closed-shell species effectively excludingmore »« less
Cited by 10
DOI: 10.1021/acs.jpca.6b11472

Full Text Available
Combined Experimental and Computational Study on the Unimolecular Decomposition of JP-8 Jet Fuel Surrogates. II: n-Dodecane (n-C₁₂H₂₆)

Journal Article Zhao, Long ; Yang, Tao ; Kaiser, Ralf I. ; ... - Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

In this paper, we investigated temperature-dependent products in the pyrolysis of helium-seeded n-dodecane, which represents a surrogate of the n-alkane fraction of Jet Propellant-8 (JP-8) aviation fuel. The experiments were performed in a high temperature chemical reactor over a temperature range of 1200 K to 1600 K at a pressure of 600 Torr, with in situ identification of the nascent products in a supersonic molecular beam using single photon vacuum ultraviolet (VUV) photoionization coupled with the analysis of the ions in a reflectron time-of-flight mass spectrometer (ReTOF). For the first time, the initial decomposition products of n-dodecane—including radicals and thermallymore »« less
Cited by 10
DOI: 10.1021/acs.jpca.6b11817

Full Text Available
Pyrolysis Pathways of the Furanic Ether 2-Methoxyfuran

Journal Article Urness, Kimberly N. ; Guan, Qi ; Troy, Tyler P. ; ... - Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

Substituted furans, including furanic ethers, derived from nonedible biomass have been proposed as second-generation biofuels. In order to use these molecules as fuels, it is important to understand how they break apart thermally. In this work, a series of experiments were conducted to study the unimolecular and low-pressure bimolecular decomposition mechanisms of the smallest furanic ether, 2-methoxyfuran. Electronic structure (CBS-QB3) calculations indicate this substituted furan has an unusually weak O - CH₃ bond, approximately 190 kJ mol^-1 (45 kcal mol^-1); thus, the primary decomposition pathway is through bond scission resulting in CH₃ and 2-furanyloxy (O - C₄H₃O) radicals. Final products from the ring opening of the furanyloxy radical include 2 CO, HCmore »« less
Cited by 5
DOI: 10.1021/acs.jpca.5b06779

Full Text Available
Reaction of the C2H radical with 1-butyne (C4H6): Low Temperature Kinetics and Isomer-Specific Product Detection

Journal Article Soorkia, Satchin ; Trevitt, Adam J ; Selby, Talitha M ; ... - Journal of Physical Chemistry

The rate coefficient for the reaction of the ethynyl radical (C{sub 2}H) with 1-butyne (H-C{triple_bond}C-CH{sub 2}-CH{sub 3}) is measured in a pulsed Laval nozzle apparatus. Ethynyl radicals are formed by laser photolysis of acetylene (C{sub 2}H{sub 2}) at 193 nm and detected via chemiluminescence (C{sub 2}H + O{sub 2} {yields} CH (A{sup 2}{Delta}) + CO{sub 2}). The rate coefficients are measured over the temperature range of 74-295 K. The C{sub 2}H + 1-butyne reaction exhibits no barrier and occurs with rate constants close to the collision limit. The temperature dependent rate coefficients can be fit within experimental uncertainties by themore »« less
Full Text Available

Similar Records