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Reaction rate of propene pyrolysis
1Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, School of Natural and Applied Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, People's Republic of China.
Journal of Computational Chemistry
|July 1, 2011
Summary
This study details propene pyrolysis reaction rates using advanced computational chemistry. Results show a first-order rate law at high temperatures, aligning with experimental data.
Area of Science:
- Chemical Kinetics
- Computational Chemistry
- Reaction Dynamics
Background:
- Propene pyrolysis is a crucial process in hydrocarbon chemistry.
- Accurate reaction rate data is essential for modeling combustion and industrial processes.
Purpose of the Study:
- To investigate the reaction rate of propene pyrolysis.
- To develop an overall reaction rate based on elementary reactions.
- To compare computational results with experimental data.
Main Methods:
- Utilized elementary reactions from Qu et al. (2009).
- Applied steady-state approximation for overall rate development.
- Determined rate constants using variational transition state theory.
- Employed density functional theory (B3PW91/6-311G(d,p)) and G3(MP2) for energy calculations.
- Used CASSCF/6-311G(d,p) and MRCISD/6-311G(d,p) for reactions without transition states.
Main Results:
- Obtained fitted three-parameter expressions for rate constants between 200-2000 K.
- Demonstrated an excellent linear relationship between the logarithm of the rate and reciprocal temperature above 400 K.
- Identified a first-order rate law at high temperatures (800-2000 K), consistent with experiments.
- Calculated apparent activation energies from zero Kelvin potential energy surface (317.3 kJ/mol) and 1200 K Gibbs free energy surface (215.7 kJ/mol).
Conclusions:
- The computational approach provides reliable propene pyrolysis rate constants.
- The apparent activation energy derived from the Gibbs free energy surface closely matches recent experimental findings.
- This work contributes to a better understanding and modeling of propene pyrolysis.
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