Combustion chemistry of aromatic hydrocarbons

Jin, Hanfeng; Yuan, Wenhao; Li, Wei; Yang, Jiuzhong; Zhou, Zhongyue; Zhao, Long; Li, Yuyang; Qi, Fei

doi:10.1016/j.pecs.2023.101076

Cited by 41 publications

(11 citation statements)

References 662 publications

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“…Under combustion conditions, the main reactions leading to the decomposition of the carbonaceous sample can be predominantly from incomplete combustion to form carbon monoxide (CO) and the rate of decomposition may depend on the type of hydrocarbons present in the sample. A large amount of aromatic compounds may result in faster combustion rates due to their high heat content in comparison to aliphatic hydrocarbons of the same carbon atoms [ 48 ]. The c-PET/d-coal samples were found to undergo complete decomposition around the 150 min.…”

Section: Resultsmentioning

confidence: 99%

“…The observed differences can be attributed to the amount of aromatic hydrocarbons present in each sample. It has been shown that aromatics such as naphthenes show greater combustion rates than their aliphatic counterparts with the same number of carbon atoms [ 48 ]. The carbonization of w-PET has also been shown to results in a char product predominantly consisting of aromatic compounds and some degree of graphitic carbon in its fixed carbon content [ 36 ].…”

Section: Resultsmentioning

confidence: 99%

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Co-Carbonization of Discard Coal with Waste Polyethylene Terephthalate towards the Preparation of Metallurgical Coke

et al. 2023

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Waste plastics such as polyethylene terephthalate (w-PET) and stockpiled discard coal (d-coal) pose a global environmental threat as they are disposed of in large quantities as solid waste into landfills and are particularly hazardous due to spontaneous combustion of d-coal that produces greenhouse gases (GHG) and the non-biodegradability of w-PET plastic products. This study reports on the development of a composite material, prepared from w-PET and d-coal, with physical and chemical properties similar to that of metallurgical coke. The w-PET/d-coal composite was synthesized via a co-carbonization process at 700 °C under a constant flow of nitrogen gas. Proximate analysis results showed that a carbonized w-PET/d-coal composite could attain up to 35% improvement in fixed carbon content compared to its d-coal counterpart, such that an initial fixed carbon content of 14–75% in carbonized discard coal could be improved to 49–86% in carbonized w-PET/d-coal composites. The results clearly demonstrate the role of d-coal ash on the degree of thermo-catalytic conversion of w-PET to solid carbon, showing that the yield of carbon derived from w-PET (i.e., c-PET) was proportional to the ash content of d-coal. Furthermore, the chemical and physical characterization of the composition and structure of the c-PET/d-coal composite showed evidence of mainly graphitized carbon and a post-carbonization caking ability similar to that of metallurgical coke. The results obtained in this study show potential for the use of waste raw materials, w-PET and d-coal, towards the development of an eco-friendly reductant with comparable chemical and physical properties to metallurgical coke.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Co-Carbonization of Discard Coal with Waste Polyethylene Terephthalate towards the Preparation of Metallurgical Coke

et al. 2023

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“…Understanding the mechanism of molecular growth chemistry in combustion of hydrocarbons is fundamental to the kinetic modeling of the formation of polycyclic aromatic hydrocarbons and particulate matters. Reaction pathways for the molecular growth of hydrocarbons are highly complicated, and various mechanisms have been suggested to contribute to the formation and growth of aromatic rings. − One of the important classes of reactions for the ring formation and growth involves recombination between resonance-stabilized radicals. ,,− In addition to the well-studied first-ring formation from the recombination of the propargyl radicals, ,, several reaction mechanisms involving the resonance-stabilized radicals have been proposed for the formation of polycyclic compounds. ,,,− …”

Section: Introductionmentioning

confidence: 99%

Ring Growth Mechanism in the Reaction between Fulvenallenyl and Cyclopentadienyl Radicals

Matsugi,

Suzuki

2024

J. Phys. Chem. A

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Recombination between resonance-stabilized hydrocarbon radicals is an important class of reactions that contribute to molecular growth chemistry in combustion. In the present study, the ring growth mechanism in the reaction between fulvenallenyl (C 7 H 5 ) and cyclopentadienyl (C 5 H 5 ) radicals is investigated computationally. The reaction pathways are explored by quantum chemical calculations, and the phenomenological and steady-state rate constants are determined by solving the multiplewell master equations. The primary reaction routes following the recombination between the two radicals are found to be as follows: formation of the adducts, isomerization by hydrogen shift reactions, cyclization to form tricyclic compounds, and their isomerization and dissociation reactions, leading to the formation of acenaphthylene. The overall process can be approximately represented as C 7 H 5 + C 5 H 5 → acenaphthylene + 2H with the bimolecular rate constant of about 4 × 10 −12 cm 3 molecule −1 s −1 . A reaction mechanism consisting of 20 reactions, including the formation, isomerization, and dissociation processes of major intermediate species, is proposed for use in kinetic modeling.

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“…30−32 Therefore, the Brønsted type elimination of ligands is excluded�the presence of −OH group can rather promote the catalytic oxidation process. Another question is how these mechanisms work in the case of aromatic hydrocarbons with very different combustion chemistry from alkanes, alkenes, and cycloalkanes, 33 i.e., in the case of the −MeCp ligand.…”

Section: Introductionmentioning

confidence: 99%

“…Other studies have shown that the elementary steps of catalytic oxidation of methane involve the dissociative chemisorption on the Pt(111) surface, dehydrogenation reactions of adsorbed −CH x species, and oxidation reactions of adsorbed reactive intermediates by adsorbed –O and –OH species. − Therefore, the Brønsted type elimination of ligands is excludedthe presence of −OH group can rather promote the catalytic oxidation process. Another question is how these mechanisms work in the case of aromatic hydrocarbons with very different combustion chemistry from alkanes, alkenes, and cycloalkanes, i.e., in the case of the −MeCp ligand.…”

Section: Introductionmentioning

confidence: 99%

Role of the Oxidizing Co-Reactant in Pt Growth by Atomic Layer Deposition Using MeCpPtMe₃ and O₂/O₃/O₂-Plasma

Li,

Klejna,

Minjauw

et al. 2024

J. Phys. Chem. C

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Atomic layer deposition (ALD) of Pt using MeCpPtMe 3 and the O 2 /O 3 /O 2 -plasma (O 2 *) at 300 °C is investigated with in vacuo X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) to gain a better understanding of the Pt growth mechanism. Most notably, the chemical state of the surface Pt atoms and the role of surface O species in Pt growth are revealed. In the MeCpPtMe 3 /O 2 process, the surface Pt atoms remain in a metallic Pt 0 state throughout the ALD cycle, and the surface O species generated by the O 2 exposure only exist as unstable adatoms, desorbing in vacuum. As for the O 3 /O 2 * processes, the surface Pt layer is oxidized to a mixture of Pt 0 , Pt 2+ O and Pt 4+ O 2 upon O 3 /O 2 * exposure and then fully reduced to Pt 0 during the precursor exposure. Surface Pt oxides are stable in a vacuum but can be reduced by hydrocarbon vapors. Quantification analysis shows that the O 3 /O 2 * processes have a much higher surface O species content than the O 2 process after the coreactant exposure, favoring precursor ligand combustion over dehydrogenation in the next precursor exposure and leading to lower surface C density after the precursor pulse. DFT reveals differences in the combustion mechanism for Me vs Cp species, during the metal precursor and coreactant pulses. Importantly, the differences in the surface O content do not significantly affect the growth per cycle. Moreover, the MeCpPtMe 3 /O 2 process with surface O species and a tailored MeCpPtMe 3 /O 2 process without surface O species, both at 300 °C, yield nearly identical growth rates and as-deposited Pt with the same chemical state. This indicates that surface O species present before the precursor exposure have little impact on the overall Pt growth, in contrast to a previous assumption.

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Combustion chemistry of aromatic hydrocarbons

Cited by 41 publications

References 662 publications

Co-Carbonization of Discard Coal with Waste Polyethylene Terephthalate towards the Preparation of Metallurgical Coke

Co-Carbonization of Discard Coal with Waste Polyethylene Terephthalate towards the Preparation of Metallurgical Coke

Ring Growth Mechanism in the Reaction between Fulvenallenyl and Cyclopentadienyl Radicals

Role of the Oxidizing Co-Reactant in Pt Growth by Atomic Layer Deposition Using MeCpPtMe₃ and O₂/O₃/O₂-Plasma

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Combustion chemistry of aromatic hydrocarbons

Cited by 41 publications

References 662 publications

Co-Carbonization of Discard Coal with Waste Polyethylene Terephthalate towards the Preparation of Metallurgical Coke

Co-Carbonization of Discard Coal with Waste Polyethylene Terephthalate towards the Preparation of Metallurgical Coke

Ring Growth Mechanism in the Reaction between Fulvenallenyl and Cyclopentadienyl Radicals

Role of the Oxidizing Co-Reactant in Pt Growth by Atomic Layer Deposition Using MeCpPtMe3 and O2/O3/O2-Plasma

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Product

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Role of the Oxidizing Co-Reactant in Pt Growth by Atomic Layer Deposition Using MeCpPtMe₃ and O₂/O₃/O₂-Plasma