Conversion of methane to benzene in CVI by density functional theory study
Kun Li1, Hejun Li2, Ningning Yan1
1State Key Laboratory of Solidification Processing, Carbon/Carbon Composites Research Center, Northwestern Polytechnical University, Xi'an, 710072, China.
Scientific Reports
|December 22, 2019
Summary
This study used density functional theory to map the methane to benzene conversion pathway in chemical vapor infiltration. Unimolecular dissociation and dehydrogenation are key steps, revealing the most favorable route for benzene formation.
Area of Science:
- Computational Chemistry
- Chemical Engineering
- Materials Science
Background:
- Methane conversion to higher hydrocarbons is crucial for chemical synthesis.
- Understanding reaction mechanisms in Chemical Vapor Infiltration (CVI) is vital for process optimization.
Purpose of the Study:
- To elucidate the detailed reaction mechanism for methane to benzene conversion.
- To identify the most favorable pathway using energetic and kinetic analyses.
Main Methods:
- Density Functional Theory (DFT) calculations with B3LYP/6-311+G(d,p).
- Geometry optimization and vibrational frequency analysis using Gaussian 09.
- Rate constant calculations via Transition State Theory (TST) and Wigner tunneling correction.
- Fitting rate constants to modified Arrhenius expressions (800-2000 K).
Main Results:
- Determined the most favorable reaction pathway for benzene formation from methane.
- Identified unimolecular dissociation as a primary mechanism.
- Observed a strong tendency towards dehydrogenation in C1-C4 species conversion.
- Confirmed pathways from C4 species to benzene (C6H6) formation.
Conclusions:
- The study provides a comprehensive mechanistic understanding of methane to benzene conversion in CVI.
- The findings highlight the importance of dehydrogenation and unimolecular dissociation.
- This research offers insights for designing efficient CVI processes for benzene production.
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