Thermal Decomposition Products Research Articles

Regulating the Performance of CO2 Adsorbents Based on the Pyrolysis Mechanism of Self-Sacrificial Templating Agents.

Previous research has proven that the pore shape and nitrogen group content of adsorbents play essential roles in determining their carbon dioxide (CO2) adsorption performance. In this article, a series of nitrogen-doped porous carbon materials were prepared for CO2 adsorption by varying the proportion of carbon nitride, the pyrolysis temperature, and the activation ratio of KOH, using chitosan as the carbon source, carbon nitride (g-C3N4 and g-C3N5) as self-sacrificing templating agents, and KOH as the activator. Among the prepared materials, T6-850-1 has the highest specific surface area (SBET) of 2336 m2/g, and T6-750-1 has the highest microporous area (Smicro) and CO2 adsorption capacity (1 bar, 298 K) of 1969 m2/g and 3.49 mmol/g, respectively. The thermal decomposition temperature and products of carbon nitride templates were characterized and tested by thermogravimetric infrared gas chromatography-mass spectrometry (TG-IR-GC-MS), and the thermal decomposition mechanisms of the two carbon nitride templates were investigated. We found that the thermal stability of the template directly affects the pore structure of the final sample as well as the type and quantity of nitrogen species.

Innovative strategies for ammonia nitrogen removal in rare earth tailings: An advanced element recycling process using leaching, chemical precipitation and adsorption

Residual ammonium salt in closed rare earth mining sites leads to elevated levels of ammonia nitrogen in the surrounding environment. To mitigate ammonia nitrogen pollution at its source, a cost-effective and environmentally friendly recycling process was proposed. This process involves leaching residual ammonia nitrogen using a magnesium sulfate solution, followed by chemical precipitation for ammonia nitrogen removal. Additionally, nitrogen can be recovered as ammonia gas through the thermal decomposition of precipitates, allowing for further ammonia nitrogen adsorption from the leachate. The residual ammonium salts leaching rate reached 96.38 % with a 0.1 mol/L magnesium sulfate solution at a flow rate of 0.6 mL/min. The chemical precipitation method achieved a maximum nitrogen removal rate of 86.87 %, with an activation energy of 2.6 kJ/mol, indicating a relatively rapid process. At 190 °C, the ammonia nitrogen release rate of precipitates was 82.5 % after 2 h of thermal decomposition. The adsorption process was consistent with pseudo-second-order kinetics models using thermal decomposition products. Overall, the comprehensive removal rate of residual ammonium salts from the closed rare earth mining site was approximately 83.3 % in recycling process, optimizing the utilization of phosphorus, magnesium, and nitrogen and achieving efficient and environmentally friendly nitrogen removal.

Thermal decomposition and atmospheric pressure chemical ionization of alanine using ion mobility spectrometry and computational study

This study investigates the impact of thermal decomposition on the ion mobility spectrum of L-alanine using ion mobility spectrometry (IMS) and computational methods. By employing a post-injection delay system, we examined the evolution of ion peaks corresponding to thermal decomposition products and their interaction with protonated alanine. Experimental results revealed that the observed ion mobility spectra predominantly feature protonated isomers and adduct ions. Computational analysis using Density Functional Theory (DFT) predicted the thermodynamically favored structures and stabilities of these products. Findings indicate that protonation at the nitrogen site in alanine is more stable than at the oxygen site, and observed peaks correspond to protonated isomers and adducts formed with ammonium ions. Further investigations showed that thermal decomposition of alanine generates ammonia, contributing to the formation of new adduct ions. This research provides new insights into the behavior of amino acids under thermal conditions with implications for analytical chemistry and biochemistry.

Investigation of the Frying Fume Composition During Deep Frying of Tempeh Using GC-MS and PTR-MS

This study employed proton transfer reaction mass spectrometry (PTR-MS) and gas chromatography–mass spectrometry (GC-MS) to identify and monitor volatile organic compounds (VOCs) in frying fumes generated during the deep frying of tempeh. The research aimed to assess the impact of frying conditions, including frying temperature, oil type, and repeated use cycles, on the formation of thermal decomposition products. A total of 78 VOCs were identified, with 42 common to both rapeseed and palm oil. An algorithm based on cosine similarity was proposed to group variables, resulting in six distinct emission clusters. The findings highlighted the prominence of saturated and unsaturated aldehydes, underscoring the role of fatty acid oxidation in shaping the frying fume composition. This study not only corroborates previous research but also provides new insights into VOC emissions during deep frying, particularly regarding the specific emission profiles of certain compound groups and the influence of frying conditions on these profiles.

Selective conversion of thermal decomposition products of ammonium perchlorate by amorphous CoSnOx

The directional transformation of products in the multiphase decomposition process of ammonium perchlorate (AP) still faces significant challenges, one of which is the conversion of greenhouse gas N2O. Furthermore, additional elucidation of the structure and potential catalytic mechanisms of catalysts with high thermal stability is imperative for the aforementioned process. This study proposes a cobalt-based amorphous oxide with high thermal stability for catalysing the thermal decomposition of AP and achieving the transformation of catalytic products from N2O to NO (and its derivatives). The results indicate that the type of catalytic decomposition products is related to the structural transformation of the catalyst, suggesting a synergistic oxidation mechanism by active oxygen and lattice oxygen. The peak decomposition temperature of AP has dropped to near the limit of 257.2 °C, TG-IR test and MD simulation results indicate the selective generation of NO under the lattice oxygen mechanism. In addition, kinetic calculations elucidated the transition of catalysts from amorphous to crystalline state in catalysis. Finally, suggestions were made for the current characterization techniques of catalysts. This study offers a reference point for the catalyst design of AP decomposition-oriented products, which is beneficial for the transition to more environmentally-friendly products.

High-Resolution Terahertz Spectroscopy for MedicalDiagnostics.

The metabolomics-based approach to diagnostics and therapy monitoring is a fast-emerging trend in modern medicine. Terahertz nonstationary spectroscopy based on the induction and disintegration of freely decaying polarization in the gas mixture during the interaction of radiation with molecules at resonance frequencies is a high-sensitivity method for studying multicomponent gas mixtures, which is promising for identifying metabolites in the thermal decomposition products of biological samples. The paper presents the results of the application of high-resolution terahertz spectroscopy to the study of biological samples taken from patients with certain diseases (pathologically changed tissues of ear-nose-throat organs and similar pathologic tissues formed in other life support systems) to search for characteristic sets of metabolites characterizing the pathology. The world's first measurements of the spectra of pathologic samples of cysts, formed in different life support systems, were carried out, which made it possible to identify similar substances in tissues having the same pathology.

Assessing vitamin E acetate as a proxy for E-cigarette additives in a realistic pulmonary surfactant model

Additives in vaping products, such as flavors, preservatives, or thickening agents, are commonly used to enhance user experience. Among these, Vitamin E acetate (VEA) was initially thought to be harmless but has been implicated as the primary cause of e-cigarette or vaping product use-associated lung injury, a serious lung disease. In our study, VEA serves as a proxy for other e-cigarette additives. To explore its harmful effects, we developed an exposure system to subject a pulmonary surfactant (PSurf) model to VEA-rich vapor. Through detailed analysis and atomic-level simulations, we found that VEA tends to cluster into aggregates on the PSurf surface, inducing deformations and weakening its essential elastic properties, critical for respiratory cycle function. Apart from VEA, our experiments also indicate that propylene glycol and vegetable glycerin, widely used in e-liquid mixtures, or their thermal decomposition products, alter surfactant properties. This research provides molecular-level insights into the detrimental impacts of vaping product additives on lung health.

An Unprecedented Tridentate-Bridging Coordination Mode of Permanganate Ions: The Synthesis of an Anionic Coordination Polymer-[CoIII(NH3)6]n[(K(κ1-Cl)2(μ2,2',2″-(κ3-O,O',O″-MnO4)2)n∞]-Containing Potassium Central Ion and Chlorido and Permanganato Ligands.

A unique compound (compound 1) with structural features including an unprecedented tridentate-bridging coordination mode of permanganate ions and an eight-coordinated (rhombohedral) κ1-chlorido and tridentate permanganato ligand in a potassium complex containing coordination polymer (CoIII(NH3)6]n[(K(κ1-Cl)2(μ2,2',2″-(κ3-O,O',O″-MnO4)2)n∞) with isolated regular octahedral hexamminecobalt(III) cation was synthesized with a yield of >90%. The structure was found to be stabilized by mono and bifurcated N-H∙∙∙Cl and N-H∙∙∙O (bridging and non-bridging) hydrogen bonds. Detailed spectroscopic (IR, far-IR, and Raman) studies and correlation analysis were performed to assign all vibrational modes. The existence of a resonance Raman effect of compound 1 was also observed. The thermal decomposition products at 500 °C were found to be tetragonal nano-CoMn2O4 spinel with 19-25 nm crystallite size and KCl. The decomposition intermediates formed in toluene at 110 °C showed the presence of a potassium- and chloride-containing intermediates combined into KCl during aqueous leaching, together with the formation of cobalt(II) nitrate hexahydrate. This means that the CoIII-CoII redox reaction and the complete decomposition of the permanganate ions occurred in the first decomposition step, with a partial oxidation of ammonia into nitrate ions.

Lithium salt preprocessing calcination strategy for a more stable layered structure of lithium-rich manganese-based cathodes

The poor cycling performance of lithium-rich manganese-based (LMR) cathodes limits their practical applications. The stability of the layered structure is closely related to the cycling performance. The high-temperature solid-state reaction between transition metal oxides (TMOs) and lithium salts promotes the formation of the layered structure, which determines the quality of the layered structure. Considering the influence of physicochemical changes of the lithium salt on the formed layered structural stability, in this work, the calcination strategy includes a short period of holding time near the melting point of Li2CO3, referred to as the lithium salt preprocessing calcination strategy, which allows the molten Li2CO3 to be fully contacted with TMOs at relatively low temperatures, alleviating the problem of Li in the thermal decomposition products of Li2CO3 not easily further reacting with TMOs. Compared to the conventional calcination procedure, this new calcination strategy reduces the oxygen vacancy concentration as well as the relative Mn3+ content on the surface of the cathodes, which significantly improves the cycling performance. In addition, the shortening of the constant high temperature calcination time effectively reduces the production energy consumption, which provides a reference for the future efficient and low-cost synthesis of electrode materials with excellent cycling performance.

Flame-Retardant Glass Fiber-Reinforced Epoxy Resins with Phosphorus-Containing Bio-Based Benzoxazines and Graphene.

This paper presents a study of the flammability and thermal decomposition products of glass fiber-reinforced epoxy resin (GFRER) with the addition of cardanol-based phosphorus-containing benzoxazine monomer (CBz) and graphene and their combinations in different proportions (up to 20 wt.%). The addition of CBz alone or in combination with graphene resulted in an increase in the limiting oxygen index (LOI) and self-extinguishing in the UL-94 HB test. The flame-retardant samples had better tensile mechanical properties than the sample without additives. The differential mass-spectrometric thermal analysis (DMSTA) of the thermal decomposition products of GFRER without additives and with the addition of CBz and graphene was carried out. CBz addition promoted the thermal decomposition of high-molecular-weight products of epoxy resin decomposition in the condensed phase and at the same time decreased the time of release of low-molecular-weight thermal decomposition products into the gas phase. Graphene addition resulted in an increase in the relative intensities of high-molecular-mass peaks compared to GFRER without additives.

The Unimolecular Decomposition Mechanism of Trimethyl Phosphate.

Trimethyl phosphate (TMP), an organophosphorus compound (OPC), is a promising fire-retardant candidate for lithium-ion battery (LIB) electrolytes to mitigate fire spread. This study aims to understand the mechanism of TMP unimolecular thermal decomposition to support the integration of a TMP chemical kinetic model into a LIB electrolyte surrogate model. Reactive intermediates and products of TMP thermal decomposition were experimentally detected using vacuum ultraviolet (VUV) synchrotron radiation and double imaging photoelectron photoion coincidence (i2PEPICO) spectroscopy. Phosphorus-containing intermediates such as PO, HPO and HPO2 were identified. Sampling effects could successfully be obviated thanks to photoion imaging, which also showed evidence for isomerization reactions upon wall collisions in the ionization chamber. Quantum chemical calculations performed for the unimolecular decomposition of TMP revealed for the first time that isomerization channels via hydrogen and methyl transfer (barrier heights of 65.9 and 72.6 kcal/mol, respectively) are the lowest-energy primary steps of TMP decomposition followed by CH3OH/CH3/CH2O or dimethyl ether (DME) production, respectively. We found an analogous DME production channel in the unimolecular decomposition of dimethyl methylphosphonate (DMMP), another important OPC fire-retardant additive with a similar molecular structure to TMP, which are not included in currently available chemical kinetic models.

Direct Comparisons of Oxygen Electro-Reduction across Molecular and Extended Oxides

Our work is focused on understanding hydrogen transfer in redox-active metal oxides as candidates for next-generation catalytic architectures, using oxygen electro-reduction as a model reaction. We are specifically studying the interrelationships between hydrogen transfer electrocatalysis across what we term the “molecules-to-materials design continuum” by directly comparing electrochemical properties of molecular tungsten-based polyoxometalates (polyoxotungstates) and extended tungsten oxides.The goal of this study was to critically compare trends of activity and selectivity towards the two-electron oxygen reduction reaction using a series of three catalyst composites derived from molecular polyoxotungstates: (1) the intact molecule adsorbed on a conductive carbon support; (2) the same composite after thermal decomposition of the molecule to bulk WO3; and (3) an intermediate state comprising the partially decomposed molecule.Catalyst composites were synthesized by wet impregnation of the polyoxotungstate (TBA)4W10O32 (TBA = tetrabutylammonium) from acetonitrile on Vulcan carbon, targeting catalyst loadings that yield well-dispersed molecular units. We then used thermal treatments over a range of temperatures associated with progressive thermal decomposition to the intermediate and fully decomposed states. Thermal decomposition reactions and products were further characterized using thermogravimetric analysis and in-situ powder X-ray diffraction. Electrocatalytic measurements were made using standard analytical protocols comprising rotating-disk electrode voltammetry of carbon-supported catalysts deposited as thin films on glassy carbon substrates.On thermal treatment, we observed that the polyoxotungstate loses stabilizing counterions with progressive rearrangement into disordered clusters and ultimately crystalline nanoparticles of orthorhombic WO3. Each of these various forms exhibit broadly similar reactivity towards the oxygen reduction reaction. Electroanalytical results suggest all three tungsten-based composites are poor oxygen reduction catalysts with activities comparable to that of the carbon support. Nonetheless, Levich analysis suggests high selectivity for 2-electron conversion to H2O2 and catalytic onsets that correlate well with distinct voltametric features corresponding to H-activation and, in the case of extended oxides, bulk proton insertion. Ongoing work is focused on extending these studies toward more tractable hydrogen transfer reactions and identifying alternative catalysts with more thermodynamically accessible mechanisms for H activation.More broadly, we hypothesize that these types of apples-to-apples comparisons between molecular and extended catalysts will reveal vital information about the impact of active site composition and electronic structure on H-transfer catalysis.

Thermal properties and decomposition products of modified cotton fibers by TGA, DSC, and Py–GC/MS

The thermal properties and pyrolysis decomposition paths of cotton fibers modified by different chemical treatments, a conventional functionalization with silane and a novel sulphation-phosphorylation approach, were studied. The effects on the fibers thermal behavior and decomposition products were investigated. The cotton fibers were characterized before and after the surface treatments by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and pyrolysis/gas chromatography–mass spectrometry (Py/GC–MS). Morphological investigation was also performed by SEM/EDS analysis to assess the treatment effects on the cotton fibers’ surface. The silanization increases the cotton hydrophobicity and thermal stability, changing the pyrolysis mechanism, favoring depolymerization over dehydration and charring. On the contrary, sulphation-phosphorylation methods cause a decrease in the onset temperature and an increase of fire resistance, and charring yield. Thermal decomposition temperatures, weight losses, and pyrolysis mechanisms and products, were fully analyzed. The results can open the way on the use of modified cotton fibers in industrial fields where fireproofing is strongly desired.

Conditions Leading to Ketene Formation in Vaping Devices and Implications for Public Health.

The outbreak of e-cigarette or vaping use-associated lung injury (EVALI) in the United States in 2019 led to a total of 2807 hospitalizations with 68 deaths. While the exact causes of this vaping-related lung illness are still being debated, laboratory analyses of products from victims of EVALI have shown that vitamin E acetate (VEA), an additive in some tetrahydrocannabinol (THC)-containing products, is strongly linked to the EVALI outbreak. Because of its similar appearance and viscosity to pure THC oil, VEA was used as a diluent agent in cannabis oils in illicit markets. A potential mechanism for EVALI may involve VEA's thermal decomposition product, ketene, a highly poisonous gas, being generated under vaping conditions. In this study, a novel approach was developed to evaluate ketene production from VEA vaping under measurable temperature conditions in real-world devices. Ketene in generated aerosols was captured by two different chemical agents and analyzed by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography with tandem mass spectrometry (LC-MS/MS). The LC-MS/MS method takes advantage of the high sensitivity and specificity of tandem mass spectrometry and appears to be more suitable than GC-MS for the analysis of large batches of samples. Our results confirmed the formation of ketene when VEA was vaped. The production of ketene increased with repeat puffs and showed a correlation to temperatures (200 to 500 °C) measured within vaping devices. Device battery power strength, which affects the heating temperature, plays an important role in ketene formation. In addition to ketene, the organic oxidant duroquinone was also obtained as another thermal degradation product of VEA. Ketene was not detected when vitamin E was vaped under the same conditions, confirming the importance of the acetate group for its generation.

Biotesting of decabromodiphenyl oxide using a multi-component test system

The results of biotesting of decabromodiphenyl oxide using a multicomponent test sys- tem are presented. It has been demonstrated that its aqueous solutions exhibit a reverse dose- dependent effect in stimulating the growth of colonies of the green algae Chlorella vulgaris and show no signs of toxic effects on Daphnia magna. During the thermal decomposition of decabro- modiphenyl oxide at a temperature of 400°C, a mixture of products is formed, one of which is bromine. The decomposition product is released into the air and possesses toxic properties, as evi- denced by stimulation of the growth of colonies of the green algae Chlorella vulgaris, as well as the death and growth abnormalities of Planorbis mollusk embryos. Therefore, water samples con- taining decabromodiphenyl oxide can be assessed for toxicity by biotesting methods, using cul- tures of green algae Chlorella vulgaris and 24-hour-old Planorbis embryos as test subjects. It is noteworthy that in the context of the prevailing perception of the safety of decabromodiphenyl ox- ide, based on its poor water solubility and low toxicity to biological organisms, there arises a need to study embryotoxic effects of the thermal decomposition products on both animals and humans.

Liquid crystalline polyurethane/POSS hybrid nanocomposites pyrolysis studies by Py-GC/MS and TG/FTIR techniques

The process of pyrolysis of liquid crystalline polyurethane (LCPU) composites with polyhedral oligomeric silsesquioxanes (POSS) has been studied using pyrolysis - gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetry/Fourier transform infrared spectroscopy (TG/FTIR) coupled thermoanalytical techniques. LCPU elastomers modified with POSS molecules with different architectures, bearing aromatic, isobutyl and cycloaliphatic moieties, yield various volatile products of pyrolysis that were collected and characterized. The TG study showed significant differences in the thermal behavior of composites studied, evidencing the influence of the silsesquioxane type on the polyurethane pyrolysis paths. FTIR study of volatile products of thermal decomposition showed the presence of characteristic bands originated from carbonyl, amine, ether, methylene, and unsaturated hydrocarbon linkages. GC/MS investigation confirmed the existence of compounds identified by the IR method. The application of both thermoanalytical methods made it possible to postulate the thermal decomposition routes of PU/POSS hybrids and to point out the main factors responsible for changes in the thermal stability.

Impact of supply and exhaust ventilation system on gas concentrations in a compartment during thermal decomposition and combustion of materials

Experiments were conducted on the detection of fires when using different operation modes of an indoor supply and exhaust ventilation system. The operating conditions of the supply and exhaust ventilation system were identified that exclude the formation of hazardous concentrations of products of thermal decomposition, gasification and combustion of class A materials (wood, cardboard and linoleum). The changes in the concentrations of the gas-air mixture components (CO, O2, CO2) were recorded in different operation modes of the supply and exhaust ventilation system and for different mechanisms of thermal decomposition and flame combustion initiation. The performance characteristics of the supply and exhaust ventilation system were determined that are necessary and sufficient for efficient operation of fire detection, containment and suppression systems.

Study on Pyrolysis Behavior of Avermectin Mycelial Residues and Characterization of Obtained Gas, Liquid, and Biochar

The proper disposal of antibiotic mycelial residue (AMR) is a critical concern due to the spread of antibiotics and environmental pollution. Pyrolysis emerges as a promising technology for AMR treatment. In this study, we investigated the effect of pyrolysis temperature on the thermal decomposition behavior and product characteristics of avermectin (AV) mycelial residues. Various characterization techniques were employed to analyze thoroughly the compositions and yields of the obtained gas, liquid, and biochar products. The results indicated that most of the organic matter such as protein, carbohydrate, and aliphatic compounds in AV mycelial residues decomposed intensely at 322 °C and tended to end at 700 °C, with a total weight loss of up to 72.6 wt%. As the pyrolysis temperature increased, the biochar yield decreased from 32.81 wt% to 26.39 wt% because of the enhanced degradation of volatiles and secondary reactions of the formed aromatic rings. Accordingly, more gas components were formed with the gas yield increased from 9.76 wt% to 15.42 wt%. For bio-oil, the contents were maintained in the range of 57.43–60.13 wt%. CO and CO2 dominated the gas components with a high total content of almost 62.37–97.54 vol%. At the same time, abundant acids, esters (42.99–48.85%), and nitrogen-containing compounds (32.14–38.70%) such as nitriles, amides, and nitrogenous heterocyclic compounds were detected for the obtained bio-oil. As for the obtained biochars, particle accumulation and irregular pores were presented on their bulk surface, which was primarily composed of calcium oxalate (CaC2O4) and calcium carbonate (CaCO3). This work can provide theoretical insights for the harmless disposal and resource recovery for AMR, contributing significantly to the field of solid waste reuse and management.

Chemical Analysis of Exhaled Vape Emissions: Unraveling the Complexities of Humectant Fragmentation in a Human Trial Study.

Electronic cigarette smoking (or vaping) is on the rise, presenting questions about the effects of secondhand exposure. The chemical composition of vape emissions was examined in the exhaled breath of eight human volunteers with the high chemical specificity of complementary online and offline techniques. Our study is the first to take multiple exhaled puff measurements from human participants and compare volatile organic compound (VOC) concentrations between two commonly used methods, proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) and gas chromatography (GC). Five flavor profile groups were selected for this study, but flavor compounds were not observed as the main contributors to the PTR-ToF-MS signal. Instead, the PTR-ToF-MS mass spectra were overwhelmed by e-liquid thermal decomposition and fragmentation products, which masked other observations regarding flavorings and other potentially toxic species associated with secondhand vape exposure. Compared to the PTR-ToF-MS, GC measurements reported significantly different VOC concentrations, usually below those from PTR-ToF-MS. Consequently, PTR-ToF-MS mass spectra should be interpreted with caution when reporting quantitative results in vaping studies, such as doses of inhaled VOCs. Nevertheless, the online PTR-ToF-MS analysis can provide valuable qualitative information by comparing relative VOCs in back-to-back trials. For example, by comparing the mass spectra of exhaled air with those of direct puffs, we can conclude that harmful VOCs present in the vape emissions are largely absorbed by the participants, including large fractions of nicotine.

On non‐hydrogen‐atom products of thermal decomposition of benzyl radical: A theoretical investigation by the transition state theory/multi‐well master equation approach

AbstractBenzyl radical (C7H7), one of the resonantly stabilized hydrocarbon radicals, is one of the significant precursors of polycyclic aromatic hydrocarbons in interstellar media and combustion engines. The unimolecular decomposition of benzyl radical is still incompletely understood despite of its importance and relatively small molecular size. The decomposition reactions of benzyl radical were investigated in the present study by using the ab initio transition state theory (TST) and the multi‐well master equation theory. Specifically, all reaction pathways on the potential energy surface of C7H7 was calculated at the level of QCISD(T)/CBS. For the reactions with multireference characters, the CASPT2(9e,7o)/aug‐cc‐pVTZ method was used to calculate the vibrational frequencies and energies of structures along the one‐dimensional reaction coordinate of the breaking bond. The high‐pressure limits of rate constants for all the reactions were obtained by using the TST except those for C7H6 + H and C6H4 + CH3 by the variational TST. The pressure‐dependent rate constants were obtained by using the multi‐well master equation simulations. The calculated rate constants agree well with available experimental and theoretical data in the literature. Moreover, the present results identify the composition of the non‐hydrogen‐atom production observed in previous experiments, which provide new insights into the reactions of aromatic compounds.