Theoretical assessment on reaction kinetics HCO and CH2OH unimolecular decomposition

Xueliang Yang, Ting Tan, Pascal Diévart, Emily A. Carter, Yiguang Ju

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

The HCO and CH2OH unimolecular decomposition reaction kinetics have been studied theoretically over a wide temperature (300-2700 K) and pressure range (0.01-1000 atm). The potential energy surfaces (PES) of CH2OH and HCO were examined at the CCSD(T)/CBS//QCISD(T)/aug-cc-pvdz level, and the thermochemistry of species are in very good agreement with the values recommended by Active Thermochemical Tables. The decomposition of HCO shows a very strong non-RRKM behavior and thus was treated using state specificity and collision-averaged unimolecular decomposition theory based on the results from a quantum scattering calculations (Keller et al., J. Chem. Phys. 1996, 105, 4983) in which the key parameters of PES agree with current calculations. The obtained theoretical rates can be presented by a Troe formula using the following parameters: kinf = 4.93E16 × T-0.93 × exp(-9927/T); κ0 = 3.94E21 × T-2.24 × exp(-9568/T); Fc = 0.852 × exp(- T/51.4) + 0.147 × exp(-T/3570) + exp(-3420/T) for N2 as bath gas; κ0 = 7.43E21×T-2.36 × exp(- 9755/T); Fc = 0.897 × exp(-T/139) + 0.103 × exp(-T/1.09E4) + exp(-4.55E3/T) for Ar as bath gas and setting Helium collisional efficiency 1.3 times larger than Argon. The results agree well with the most of the currently available HCO decomposition experimental data. The recommended Troe formula for CH2OH decomposition rate is: kinf = 6.535E11 × T0.567 × exp(-20744/T); κ0 = 4.145E31 × T-4.517 × exp(-21116/T); Fc = 0.578 × exp(-T/2.30) + 0.422 × exp(-T/3174) + exp(-1.47E6/T) for Ar as bath gas. The newly obtained rates are very different from the recommendation by Baulch et al. (J. Phys. Chem. Ref. Data, 2005, 34, 757) based on some empirical estimations, but fall in the right range of scattered experimental measurements in the literature. The combustion simulations using these recommended rates result in much better agreement with experimental measured flame speed.

Original languageEnglish (US)
Title of host publication8th US National Combustion Meeting 2013
PublisherWestern States Section/Combustion Institute
Pages1732-1740
Number of pages9
ISBN (Electronic)9781627488426
StatePublished - 2013
Event8th US National Combustion Meeting 2013 - Park City, United States
Duration: May 19 2013May 22 2013

Publication series

Name8th US National Combustion Meeting 2013
Volume2

Other

Other8th US National Combustion Meeting 2013
CountryUnited States
CityPark City
Period5/19/135/22/13

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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    Yang, X., Tan, T., Diévart, P., Carter, E. A., & Ju, Y. (2013). Theoretical assessment on reaction kinetics HCO and CH2OH unimolecular decomposition. In 8th US National Combustion Meeting 2013 (pp. 1732-1740). (8th US National Combustion Meeting 2013; Vol. 2). Western States Section/Combustion Institute.