Influence of H2O and O2 on the Homogeneous Conversion of Toluene and the Underlying Reaction Mechanisms

J Cui and HC Liu and B Xu and FC Wang and XL Yin and CZ Wu, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 63, 5678-5688 (2024).

DOI: 10.1021/acs.iecr.4c00113

In this study, the impact of H2O and O-2 on the homogeneous conversion of toluene at various temperatures and concentrations was investigated. Molecular dynamics simulations were performed using the ReaxFF force field to decipher the underlying high-temperature reaction dynamics among toluene, H2O, and O-2. In the presence of both H2O and O-2, the toluene conversion efficiency reached 98%, primarily producing H2 and CO. Toluene conversion and H-2 and CO generation were strengthened under 1-2% O-2 with 5-15% H2O. Conversely, elevated O2 (3%) and H2O (25-35%) hindered the combustible gas yield. Two principal H2 and CO formation pathways were identified: (1) Under high temperatures, H2O and O-2 generate OH radicals, promoting toluene side chain conversion into (CHO) entities, which subsequently break down into H2 and CO. (2) The toluene- benzene ring disintegrates under OH radical activity. The resulting fragments, in the presence of H2O, produce H-2 and CO. The simulation insights were validated by D2O and O-18(2) isotope labeling experiments.

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