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Reaction rate of propene pyrolysis
Author(s) -
Han Peipei,
Su Kehe,
Liu Yan,
Wang Yanli,
Wang Xin,
Zeng Qingfeng,
Cheng Laifei,
Zhang Litong
Publication year - 2011
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.21854
Subject(s) - reaction rate constant , chemistry , transition state theory , propene , activation energy , elementary reaction , potential energy surface , thermodynamics , logarithm , reaction rate , density functional theory , computational chemistry , atomic physics , physics , quantum mechanics , kinetics , mathematics , molecule , organic chemistry , mathematical analysis , catalysis
The reaction rate of propene pyrolysis was investigated based on the elementary reactions proposed in Qu et al., J Comput Chem 2009, 31, 1421. The overall reaction rate was developed with the steady‐state approximation and the rate constants of the elementary reactions were determined with the variational transition state theory. For the elementary reaction having transition state, the vibrational frequencies of the selected points along the minimum energy path were calculated with density functional theory at B3PW91/6‐311G(d,p) level and the energies were improved with the accurate model chemistry method G3(MP2). For the elementary reaction without transition state, the frequencies were calculated with CASSCF/6‐311G(d,p) and the energies were refined with the multireference configuration interaction method MRCISD/6‐311G(d,p). The rate constants were evaluated within 200–2000 K and the fitted three‐parameter expressions were obtained. The results are consistent with those in the literatures in most cases. For the overall rate, it was found that the logarithm of the rate and the reciprocal temperature have excellent linear relationship above 400 K, predicting that the rate follows a typical first‐order law at high temperatures of 800–2000 K, which is also consistent with the experiments. The apparent activation energy in 800–2000 K is 317.3 kJ/mol from the potential energy surface of zero Kelvin. This value is comparable with the energy barriers, 365.4 and 403.7 kJ/mol, of the rate control steps. However, the apparent activation energy, 215.7 kJ/mol, developed with the Gibbs free energy surface at 1200 K is consistent with the most recent experimental result 201.9 ± 0.6 kJ/mol. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011