Kinetics and Products of Vinyl + 1,3-Butadiene, a Potential Route to Benzene
Name
Green_Kinetics and products.pdf
Size
2.78 MB
Format
Adobe PDF
Checksum (MD5)
83f54c7641a556272b027e00730bdb15
Author(s)
Liu, Guozhu
Elsamra, Rehab M. I.
Buras, Zachary
Dames, Enoch E.
Merchant, Shamel S.
Green, William H
Date Issued
April 2015
Journal
The Journal of Physical Chemistry A
Publisher
American Chemical Society (ACS)
Citation
Buras, Zachary J. et al. “Kinetics and Products of Vinyl + 1,3-Butadiene, a Potential Route to Benzene.” The Journal of Physical Chemistry A 119.28 (2015): 7325–7338. © 2015 American Chemical Society
Version
Author's final manuscript
Abstract
The reaction between vinyl radical, C[subscript 2]H[subscript 3], and 1,3-butadiene, 1,3-C[subscript 4]H[subscript 6], has long been recognized as a potential route to benzene, particularly in 1,3-butadiene flames, but the lack of reliable rate coefficients has hindered assessments of its true contribution. Using laser flash photolysis and visible laser absorbance (λ = 423.2 nm), we measured the overall rate coefficient for C[subscript 2]H[subscript 3] + 1,3-C[subscript 4]H[subscript 6], k[subscript 1], at 297 K ≤ T ≤ 494 K and 4 ≤ P ≤ 100 Torr. k[subscript 1] was in the high-pressure limit in this range and could be fit by the simple Arrhenius expression k[subscript 1] = (1.1 ± 0.2) × 10[superscript –12] cm[superscript 3] molecule[superscript –1] s[superscript –1] exp(−9.9 ± 0.6 kJ mol[superscript –1]/RT). Using photoionization time-of-flight mass spectrometry, we also investigated the products formed. At T ≤ 494 K and P = 25 Torr, we found only C[subscript 6]H[subscript 9] adduct species, while at 494 K ≤ T ≤ 700 K and P = 4 Torr, we observed ≤∼10% branching to cyclohexadiene in addition to C[subscript 6]H[subscript 9]. Quantum chemistry master-equation calculations using the modified strong collision model indicate that n-C[subscript 6]H[subscript 9] is the dominant product at low temperature, consistent with our experimental results, and predict the rate coefficient and branching ratios at higher T where chemically activated channels become important. Predictions of k[subscript 1] are in close agreement with our experimental results, allowing us to recommend the following modified Arrhenius expression in the high-pressure limit from 300 to 2000 K: k[subscript 1] = 6.5 × 10[superscript –20] cm[superscript 3] molecule[superscript –1] s[superscript –1] T[superscript 2.40] exp(−1.76 kJ mol[superscript –1]/RT).
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1021/jp512705r
