Final Report: Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: NJIT Report

EPA Grant Number: R826371C009
Subproject: this is subproject number 009 , established and managed by the Center Director under grant R826371
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States
Center Director: Seinfeld, John
Title: Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: NJIT Report
Investigators: Bozzelli, Joseph W.
Institution: New Jersey Institute of Technology
EPA Project Officer: Shapiro, Paul
Project Period: April 15, 1998 through April 14, 2003
RFA: Special Opportunity in Tropospheric Ozone (1997) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Air

Objective:

The main objectives of this research project were to analyze thermochemical properties for reactants, intermediates, products, and transition states important in the acetyl radical (CH3C·(= O)) + O2 reaction system with density functional and ab initio calculations to evaluate reaction paths and kinetics in both oxidation and pyrolysis.

Summary/Accomplishments (Outputs/Outcomes):

Thermochemical properties for reactants, intermediates, products, and transition states important in the acetyl radical (CH3C· (= O)) + O2 reaction system were analyzed with density functional and ab initio calculations to evaluate reaction paths and kinetics in both oxidation and pyrolysis (see Figure 1). Enthalpies of formation (delta2Hf°298) were determined using isodesmic reaction analysis at the complete basis set quadrator (CBSQ) composite and density functional levels. Entropies (S°298) and heat capacities (Cp°[T]) were determined using geometric parameters and vibrational frequencies obtained at the HF/6-31G(d’) level of theory. Internal rotor contributions were included in S and Cp(T) values. The acetyl radical was added to O2 to form a CH3C(= O)OO· peroxy radical with a 35 kcal/mol well depth. The peroxy radical underwent dissociation back to reactants, decomposed to products, CH2C = O + HO2 via concerted HO2 elimination (Ea = 34.58 kcal/mol) or isomerized via hydrogen shift (Ea = 26.42) to form a C·H2C(= O)OOH isomer. This C·H2C(= O)OOH isomer underwent beta scission to products, CH2C = O + HO2 (Ea = 31.41), decomposed to a cyclic ketone, YCOC(= O) + OH via OH elimination (Ea = 19.97, Y = cyclic), decomposed to a diradical, C·H2CO(O·) + OH via simple RO-OH bond cleavage (Ea = 27.57), or was isomerized back to the CH3C(=O)OO· isomer.

Rate constants were estimated as a function of pressure and temperature using Quantum Rice-Ramsperger-Kassel (QRRK) analysis for k(E) and the master equation for falloff. Important reaction products are stabilization of CH3C(= O)OO· peroxy adduct at low temperature and at higher temperatures, formation of a diradical, C·H2CO(O·), + OH and CH2C = O + HO2 are dominant. delta2Hf°298 values were estimated for the following compounds at the CBSQ level: (kcal/mol) CH3C·(= O) (-3.08), C·H2CHO (3.52), CH3C(= O)OOH (-84.80), CH3C(= O)OO· (-38.57), C·H2C(= O)OOH (-32.95), and YCOC(= O) (-44.42). A mechanism for pyrolysis and oxidation of the acetyl radical was constructed. Reaction of acetyl with O2 versus unimolecular decomposition was evaluated versus temperature and pressure. Related oxygen bonds in acetyl hydroperoxide were predicted to be stronger than corresponding bonds in alkyl hydroperoxide.

Figure 1. Potential Energy Diagram of CH3CO· + O2

Thermochemical properties for important species in the formyl methyl radical (C·H2CHO) + O2 reaction system were analyzed to evaluate reaction paths and kinetics in both oxidation and pyrolysis (see Figure 2). Enthalpies of formation (delta2Hf°298) were determined using isodesmic reaction analysis at the CBSQ composite and density functional levels. Entropies (S°298) and heat capacities (Cp°[T]) were determined using geometric parameters and vibrational frequencies obtained at the HF/6-31G(d’) level of theory. Internal rotor contributions were included in S and Cp(T) values.

The formyl methyl radical was added to O2 to form a C(OO·)H2CHO peroxy radical with a 27.5 kcal/mol well depth. The peroxy radical can undergo dissociation back to reactants, decompose to CH2CO + HO2 via HO2 elimination, or isomerize via hydrogen shift to form a C(OOH)H2C·O. This C(OOH)H2C·O isomer can undergo beta scission to products, CH2CO + HO2, decompose to CO + CH2O + OH, or decompose to a diradical, CH2O·C·O + OH via simple RO–OH bond cleavage. Rate constants were estimated as a function of pressure and temperature using QRRK analysis for k(E) and master equation for falloff.

Important reaction products included the stabilization of the C(OO·)H2CHO peroxy adduct at low temperature and CO + CH2O + OH products via H shift at high temperature. delta2Hf°298 values were estimated for the following compounds at CBSQ level: C·H2CHO (3.52), C(OOH)H2CHO (-56.19), C(OO·)H2CHO (-21.01), and C(OOH)H2C·O (-19.64) (kcal/mol). A mechanism for pyrolysis and oxidation of the formyl methyl radical was constructed, and the reaction of the formyl methyl radical with O2 versus unimolecular decomposition was evaluated.

Figure 2. Potential Energy Diagram of C·H2CHO + O2

Thermochemical properties for reactants, intermediates, products, and transition states important in the ketene (CH2 = C = O) + H reaction system and unimolecular reactions of the stabilized formyl methyl (C·H2CHO) and the acetyl radicals (CH3C·O) were analyzed with density functional and ab initio calculations (see Figure 3). Enthalpies of formation (delta2Hf°298) were determined using isodesmic reaction analysis at the complete basis set (CBS)-quadratic configuration interaction (QCI)/atomic pair natural orbital (APNO) and the CBSQ levels. Entropies (S°298) and heat capacities (Cp°[T]) were determined using geometric parameters and vibrational frequencies obtained at the HF/6-311G(d,p) level of theory. Internal rotor contributions were included in S and Cp(T) values. A hydrogen atom was added to the CH2- group of the ketene to form the acetyl radical, CH3C·O (Ea = 2.49 in CBS-QCI/APNO units: kcal/mol). The acetyl radical can undergo beta scission back to reactants, CH2 = C = O + H (Ea = 45.97), isomerize via hydrogen shift (Ea = 46.35) to form the slightly higher energy, formyl methyl radical, C·H2CHO, or decompose to CH3 + CO (Ea = 17.33). The hydrogen atom also can add to the carbonyl group to form C·H2CHO (Ea = 6.72). This formyl methyl radical can undergo beta scission back to reactants, CH2 = C = O + H (Ea = 43.85), or isomerize via hydrogen shift (Ea = 40.00) to form the acetyl radical isomer, CH3C·O, which can decompose to CH3 + CO. Rate constants were estimated as a function of pressure and temperature using quantum QRRK analysis for k(E) and the master equation for falloff. Important reaction products were CH3 + CO via decomposition at both high and low temperatures. A transition state for direct abstraction of hydrogen atom on CH2 = C = O by H to form, ketenyl radical plus H2 was identified with a barrier of 12.27, at the CBS-QCI/APNO level. delta2Hf°298 values were estimated for the following compounds at the CBS-QCI/APNO level: CH3C·O (-3.27), C·H2CHO (3.08), CH2 = C = O (-11.89), and HC·CO (41.98) (kcal/mol).

Figure 3. Potential Energy Diagram of CH2 = C = O + H

The allyl radical (CH2 = CHCH2·) + O2 reaction system was analyzed with density functional and ab initio calculations to evaluate thermochemical properties, reaction paths, and kinetics in oxidation. Enthalpies of formation (delta2Hf°298) were determined using isodesmic reaction analysis at the CBSQ//B3LYP/6-31G(d,p) composite and density functional levels. Entropies (S°298) and heat capacities (Cp°[T]) were determined using geometric parameters and vibrational frequencies obtained at the B3LYP/6-31G(d,p) level of theory. Internal rotor contributions were included in S and Cp(T) values. The allyl radical was added to O2 to form an energized peroxy adduct (CH2 = CHCH2OO·)* with a shallow well (ca. 19 kcal/mol), which predominantly dissociated back to reactants under combustion conditions. The reaction channels of the (CH2 = CHCH2OO·)* adduct included reverse reaction to reactants, stabilization to CH2 = CHCH2OO· radical (delta2Hf°298 = 21.02 kcal/mol in CBSQ), and isomerization via hydrogen shift with subsequent beta scission or R·O—OH bond cleavage. The (CH2 = CHCH2OO·)* adduct also can cyclize to four- or five-member cyclic peroxide-alkyl radicals, C·H2YCCOO and YCC·COO (Y = cyclic, delta2Hf°298 = 40.18 and 19.18, respectively). CH2 = CHCH2OO· cyclization to four- or five-member cyclic peroxides required barriers that are higher than reverse reaction (Ea = 29.71 and 25.07, respectively). All the product formation pathways of allyl radical with O2 involved barriers that are above the energy of the initial reactants.

Rate constants were estimated as a function of pressure and temperature using QRRK analysis for k(E) and master equation for fall-off. CH2 = CHCH2OO· adduct, cyclic isomers, and H-shift isomers exhibit significant falloff at higher temperatures. Important reactions include the stabilization of CH2 = CHCH2OO· adduct at low temperature and allene + HO2 products via a HO2 molecular elimination path, YCC·COO via cyclization, and H transfer from primary vinyl group to peroxy radical; beta-scission reaction lead to C2H2 + CH2O + OH at higher temperature. delta2Hf°298 values were estimated for the following compounds at CBSQ level. CH2 = CHCH2· (40.06), CH2 = CHCH2OOH (-13.49), CH2 = CHCH2OO· (21.02), C·H2 = CHCH2OOH (46.77), CH2 = C·HCH2OOH (44.58), C·H2YCCOO (40.18), and YCC·COO (19.18) (kcal/mol). A mechanism was developed, and Chemkin was used to determine important initial reaction pathways.


Journal Articles on this Report : 10 Displayed | Download in RIS Format

Other subproject views: All 10 publications 10 publications in selected types All 10 journal articles
Other center views: All 49 publications 46 publications in selected types All 46 journal articles
Type Citation Sub Project Document Sources
Journal Article Bozzelli JW, Jung D. Theoretical investigation on stability of the C•H2OCl radical. Journal of Physical Chemistry A 2001;105(16):3941-3946. R826371 (Final)
R826371C009 (Final)
  • Full-text: ACS-Full Text HTML
    Exit
  • Abstract: ACS-Abstract
    Exit
  • Other: ACS-Full Text PDF
    Exit
  • Journal Article Jung D, Chen C-J, Bozzelli JW. Structures, rotation barrier, and thermodynamic properties ΔHf°298, S°298, and Cp(T) of chloromethyl hypochlorites CH3OCl, CH2ClOCl, CHCl2OCl, and CCl3OCl. Journal of Physical Chemistry A 2000;104(42):9581-9590. R826371 (Final)
    R826371C009 (Final)
    R824970 (Final)
  • Full-text: ACS-Full Text HTML
    Exit
  • Abstract: ACS-Abstract
    Exit
  • Other: ACS-Full Text PDF
    Exit
  • Journal Article Lee J, Chen C-J, Bozzelli JW. Thermochemical and kinetic analysis of the acetyl radical (CH3C •O) + O2 reaction system. Journal of Physical Chemistry A 2002;106(31):7155-7170. R826371 (Final)
    R826371C009 (Final)
  • Full-text: ACS-Full Text HTML
    Exit
  • Abstract: ACS-Abstract
    Exit
  • Other: ACS-Full Text PDF
    Exit
  • Journal Article Lee J, Bozzelli JW. Reaction of H + ketene to formyl methyl and acetyl radicals and reverse dissociations. International Journal of Chemical Kinetics 2003;35(1):20-44. R826371 (Final)
    R826371C009 (Final)
  • Abstract: Wiley Online-Abstract
    Exit
  • Journal Article Lee J, Bozzelli JW. Thermochemical and kinetic analysis of the formyl methyl radical + O2 reaction system. Journal of Physical Chemistry A 107(19):3778-3791. R826371 (Final)
    R826371C009 (Final)
  • Abstract: ACS-Abstract
    Exit
  • Journal Article Sun H, Chen C-J, Bozzelli JW. Structures, intramolecular rotation barriers, and thermodynamic properties (enthalpies, entropies and heat capacities) of chlorinated methyl hydroperoxides (CH2ClOOH, CHCl2OOH, and CCl3OOH). Journal of Physical Chemistry A 2000;104(35):8270-8282. R826371C009 (Final)
    R824970 (Final)
  • Full-text: ACS-Full Text HTML
    Exit
  • Abstract: ACS-Abstract
    Exit
  • Other: ACS-Full Text PDF
    Exit
  • Journal Article Sun H, Bozzelli JW. Structures, intramolecular rotation barriers, and thermochemical properties of radicals derived from H atom loss in mono-, di-, and trichloromethanol and parent chloromethanols. The Journal of Physical Chemistry A 2001;105(18):4504-4516. R826371 (Final)
    R826371C009 (Final)
  • Full-text: ACS-Full Text HTML
    Exit
  • Abstract: ACS-Abstract
    Exit
  • Other: ACS-Full Text PDF
    Exit
  • Journal Article Sun H, Bozzelli JW. Structures, intramolecular rotation barriers, and thermochemical properties:ethanol, α-monoethanols, dichloroethanols, and corresponding radicals derived from H atom loss. Journal of Physical Chemistry A 2001;105(41):9543-9552. R826371 (Final)
    R826371C009 (Final)
  • Full-text: ACS-Full Text HTML
    Exit
  • Abstract: ACS-Abstract
    Exit
  • Other: ACS-Full Text PDF
    Exit
  • Journal Article Zhu L, Chen C-J, Bozzelli JW. Structures, rotational barriers, and thermodynamic properties of C2 vinyl and chlorovinyl alcohols and additivity groups. Journal of Physical Chemistry A 2000;104(40):9197-9206. R826371C009 (Final)
    R824970 (Final)
  • Full-text: ACS-Full Text HTML
    Exit
  • Abstract: ACS-Abstract
    Exit
  • Other: ACS-Full Text PDF
    Exit
  • Journal Article Zhu L, Bozzelli JW. Structures, rotational barriers, and thermochemical properties of chlorinated aldehydes and the corresponding acetyl (CC•=O) and formyl methyl radicals (C•C=O) and additivity groups. Journal of Physical Chemistry A 2002;106(2):345-355. R826371 (Final)
    R826371C009 (Final)
  • Full-text: ACS-Full Text HTML
    Exit
  • Abstract: ACS-Abstract
    Exit
  • Other: ACS-Full Text PDF
    Exit
  • Supplemental Keywords:

    air quality modeling, ambient air, particulate, ozone, environmental chemistry, California, CA, Northeastern United States., RFA, Scientific Discipline, Air, particulate matter, Environmental Chemistry, Analytical Chemistry, tropospheric ozone, Atmospheric Sciences, atmospheric particulate matter, fine particles, ozone, fine particulates, airborne particulate matter, chemical composition, air sampling, air pollution models, air quality model, thermochemical properties, atmospheric aerosol particles, hydrocarbons, California, aersol particles, atmospheric chemistry, fine particle formation

    Progress and Final Reports:

    Original Abstract
  • 1998
  • 1999
  • 2000
  • 2001

  • Main Center Abstract and Reports:

    R826371    Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R826371C001 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Cal Tech, UC-Riverside, UC-San Diego, UC-Davis Report
    R826371C002 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Cal Tech, Carnegie Mellon, Georgia Institute, NJIT, Oregon Institute, UC-Irvine, UC-Riverside Report
    R826371C003 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Cal Tech Report
    R826371C004 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: California - Irvine Report
    R826371C005 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Carnegie Mellon Report
    R826371C006 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Carnegie Mellon Report
    R826371C007 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: UC-Riverside
    R826371C008 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: Oregon Health and Science Report
    R826371C009 Research Consortium on Ozone and Fine Particle Formation in California and in the Northeastern United States: NJIT Report