Trimethylolethane trinitrate (TMETN) is a promising insensitive nitrate ester plasticizer for replacing highly sensitive nitroglycerin (NG), but its high-temperature ignition behavior, pyrolysis chemistry, and detailed condensed-phase decomposition mechanism remain insufficiently understood. In this work, the ignition, pyrolysis, and thermal decomposition mechanism of TMETN were systematically investigated by combining high-pressure shock tube experiments, ReaxFF reactive molecular dynamics (ReaxFF MD) simulations, and high-level quantum chemical calculations. Ignition delay times (IDTs) were measured at 5, 10, and 20 bar in Ar and Ar/O2 atmospheres, and 14 major gaseous pyrolysis products were identified under high-temperature and high-pressure conditions. ReaxFF MD simulations were performed to analyze the temporal evolution of key intermediates and final products, while quantum chemical calculations were carried out to clarify the thermodynamic and kinetic preference between NO2 and HONO elimination pathways. The results show that: (1) TMETN ignition exhibits a strong pressure dependence. In Ar, the measured IDTs decrease from 0.78–0.876 ms at 5 bar to 0.52–0.609 ms at 10 bar and 0.23–0.301 ms at 20 bar; in Ar/O2, the IDTs decrease from 0.734–0.832 ms at 5 bar to 0.493–0.580 ms at 10 bar and 0.208–0.273 ms at 20 bar. (2) As the temperature increases, the concentrations of hydrocarbon products increase, whereas those of oxygen-containing intermediates such as methanol and formaldehyde decrease, indicating that higher temperatures promote the deep cracking and secondary decomposition of TMETN. (3) ReaxFF MD simulations capture the temperature-dependent evolution trends of representative products and reveal that O–NO2 bond cleavage accompanied by NO2 release dominates the initial decomposition stage of TMETN. (4) Quantum chemical calculations further demonstrate that NO2 elimination is generally more favorable than the competing HONO elimination pathway in terms of reaction barriers, reaction enthalpies, and temperature-dependent rate constants. These results indicate that the thermal decomposition of TMETN is mainly initiated by nitrate ester bond cleavage, followed by NOx/HONO-related secondary reactions and the formation of stable small-molecule products such as N2, CO2, and H2O. This work provides quantitative ignition data and a cross-scale mechanistic interpretation of TMETN thermal decomposition, offering a theoretical basis for kinetic model development and the safe application of insensitive energetic plasticizers.

Amines are a class of nitrogen-containing compounds formed by substituting hydrogen atoms in ammonia molecules with hydrocarbon groups, they are regarded as potential biomass-derived fuels. Current research primarily focuses on primary and secondary amines, whereas the combustion characteristics of tertiary amine fuels remain insufficiently understood. Therefore, this study selected trimethylamine (TMA), the simplest tertiary amine, to systematically investigate its combustion and pyrolysis behaviors. Experimentally, a high-pressure shock tube was employed to measure the ignition delay times of TMA/air mixtures under the following conditions: equivalence ratios of 0.5, 1.0, and 2.0; pressures of 5 bar and 10 bar; and temperatures ranging from 1050 K to 1450 K. The laminar flame speeds of TMA/air mixtures were determined in a high-pressure isochoric reactor at an initial temperature of 333 K and pressures of 1 bar and 2 bar. Pyrolysis experiments on TMA with an initial concentration of 2000 ppm were conducted using a single-pulse shock tube over the temperature range of 1000-1550 K, yielding the distribution of primary pyrolysis products. A detailed chemical kinetic model for TMA was developed using a hierarchical approach. The model predictions are in reasonable agreement with experimental measurements of ignition delay times, laminar flame speeds, and pyrolysis product distributions over the investigated temperature, pressure, and equivalence ratio ranges. This study provides systematic experimental data and a refined kinetic mechanism to support the understanding of oxidation and pyrolysis processes of nitrogen-containing biomass fuels.

RDX (hexogen) can rapidly release large amounts of heat and gaseous products during explosion, while aluminum powder provides sustained heat release. As a result, RDX/Al mixed dust usually exhibits higher energy release intensity and greater explosion severity. In this study, computational fluid dynamics (CFD) simulations and experiments were combined to investigate the explosion behavior of RDX, aluminum (Al), and RDX/Al mixed dusts in a 5 L spherical explosion chamber, with emphasis on the effects of dust concentration and mixing ratio. The results show that, during the dispersion stage, dust particles rise along the chamber wall under the action of airflow, recirculate from the upper region, and then descend toward the chamber center, finally forming a high-concentration dust column. For RDX dust, the flame first propagates downward along the central descending airflow and then expands upward under the action of high-temperature and high-pressure gases. Meanwhile, the mass fractions of CO2, H2O, CO, and H2 increase with increasing dust concentration. Aluminum powder releases more heat during explosion but shows smaller fluctuations in temperature evolution than RDX dust. For RDX/Al mixed dusts with different mixing ratios, the overall flame-front propagation direction is generally consistent, whereas the flame-front propagation velocity and temperature evolution differ significantly. In addition, the final mass fractions of CO and H2 first increase and then decrease with increasing RDX content. These findings provide valuable insights for explosion risk assessment and safety protection of energetic-material dusts.

Low- and ultra-low-concentration methane in strongly diluted process streams represents both an energy-utilization challenge and a target for greenhouse-gas mitigation. However, although the fundamental reaction mechanisms of methane oxidation and...

Due to its higher energy density, clean combustion products, and a significant reduction in two-phase flow heat loss, Boron powder is widely used in solid propellants as an additive to enhance combustion reactivity. However, the lack of experimental data on nanoscale boron particle combustion makes its combustion process unclear. In this study, Ignition delay times (IDT) and burn time characteristics for ultrafine boron particles (30 nm) were systematically investigated in 5 different oxidant conditions at 2.0 bar using a shock tube experimental system. For comparison, aluminium particles (50 nm) and magnesium particles (30 mu m) selected as control groups and had also been conducted investigation works under the same experimental conditions as boron. IDTs for all three metals were significantly higher in H2O atmospheres compared to other oxidants, and this aligns with the conclusions drawn by Wu [1], further indicating that as the H2O concentration increases, the combustion mode of the three particles transitions towards a diffusion-controlled regime. For boron particles in multi-component oxidants, adding oxygen consistently increased IDT across the tested temperature range compared to oxygen-free conditions. Meanwhile, by calculating the Knudsen and Fourier numbers, the physical heat-conduction time of boron particles in profile-5 was analysed with molecular collision theory, which only takes 0.1 microseconds, so it could be ignored compared to IDT. SEM and energy spectra analysis characterized boron combustion products under different oxidants. Combustion efficiency (eta) for boron was calculated by comparing reactive and oxide contents in samples and products. Results showed that steeper slopes in boron burn time data (indicating lower activation energy) correlated with lower combustion efficiency. The results of the current study provide data for the construction of a detailed combustion chemical kinetic mechanism of the tree metal particles, and the design of metal-containing fuel engines.

This study presents an experimental shock tube (ST) and kinetic modeling investigation of the pyrolysis and ignition behavior of pure RP-3 jet fuel, pure hydro-processed esters and fatty acids (HEFA), sustainable aviation fuel (SAF), and their blends. The volume ratios of SAF in the three blends are 40 % (R60H40), 60 % (R40H60), and 80 % (R20H80). The pyrolysis products are studied using a single pulse shock tube (SPST), at T = 900-1700 K and p = 10 bar. Ignition delay times are recorded using a high-pressure shock tube (HPST) facility, in the temperature T range of 984-1431 K, at p = 10-20 bar, and at phi = 0.5-2.0 in air. Based on the same surrogate components consisting of n-decane, n-dodecane, n-tetradecane and methylcyclohexane, a detailed kinetic model was developed to analyze the pyrolysis and oxidation behavior of the pure jet fuels and their blends using GalwayMech1.0 as the core mechanism. Methane, acetylene, ethylene, and propene are the most abundant products. Flux and sensitivity analyses indicate that a contrast in the effect of C2H4 production and consumption between RP-3 and other fuels is evident. The decomposition reaction (C)over dot(14)H(29)-3 <-> nC(13)D1 + (C)over dotH(3) and isomerization reactions (C)over dot(14)H(29)-7 <<-> (C)over dot(14)H(29)-3 and (C)over dot(14)H(29)-6 <-> (C)over dot(14)H(29)-3 of (C)over dot(14)H(29) at different reaction sites are key contributors to the formation and consumption of C2H4 for pure HEFA SAF and its blends except for pure RP-3. The ignition delay times of the five fuels atp =10 bar show a clear point of intersection at a critical temperature of similar to 1250 K. It is because of the competition between reactivity-dominating reactions at higher temperature and hydrogen atom abstraction reactions from the fuel (nC(14)H(30)) by H(O)over dot(2) radicals at lower temperatures (984-1250 K).

The energy release characteristics of traditional propellants critically influence interior ballistic performance and safety; however, achieving a balance between high loading density and high muzzle velocity has long been constrained by bottlenecks. Step energy-releasing propellants enable temporal control of energy output through structural design, offering a novel approach to address these challenges. In this study, glycidyl azide polymer (GAP) was incorporated into the propellant system, and two coating system formulations (GAP-isocyanate and PEG-GAP-isocyanate) were designed and prepared, yielding three distinct formulations. Mechanical and rheological tests indicated that tion 1 and formulation 2 exhibited higher storage moduli and loss moduli, demonstrating superior viscoelasticity, whereas formulation 3 achieved a tensile strength of 9.75 MPa, and the structural bearing capacity is better.Subsequently, the effects of coating formulation and thickness on step combustion behavior were investigated. Closed bomb tests indicated that the end-burning structure exhibited significant step energy release characteristics, whereas the whole-burning structure only produced delayed combustion. The end-burning propellant coated with formulation 1 achieved the optimal step energy release performance, and increasing the coating thickness extended the platform duration by up to approximately 100 ms. These results confirm that the design of GAP-based coating structures enables controllable step energy release during the propellant energy release process.

Metal–organic frameworks (MOFs) have significant potential in electrochemical sensors, but the guest molecules and residual solvents in the pores often block the active sites and limit the reaction kinetics. One-dimensional nanostructures can provide direct conduction pathways and shorten ion diffusion distances, thereby enhancing electron transport and electrode contact. Meanwhile, fluorine-incorporated MOF materials leverage the high electronegativity of fluorine to substitute oxygen, suppress oxidation to widen the voltage window, and improve stability through enhanced hydrophobicity. In this work, 4-fluorosalicylic acid (4FSA) was used as the ligand and benzimidazole (Bim) was introduced to adjust the coordination environment, and one-dimensional Bim4FSA-MOF nanorods were successfully constructed. While the guest molecules were largely removed, the nickel sites were thereby activated and the pore size was enlarged. Due to the synergistic effect of one-dimensional nanostructure-promoted electron transport and the Ni(OH)2/NiOOH dynamic active center, the B-250 composite exhibited excellent performance in a glucose electrochemical sensor. The optimized sensor delivered a detection limit of 0.022 μM and a detection time of 0.9 s, along with a sensitivity value of 2986.45 μA mM−1 cm−2, which provides a new strategy for the design of efficient MOF-based electrochemical sensor interface.

The mixtures of nitrous oxide (N2O) and ammonia (NH3) has received increasing attention as a promising green propellant for dual‑mode chemical‑electric space propulsion, yet fundamental combustion data for this system remain scarce. To decouple and examine the chemical coupling between NH3 oxidation and N2O - driven reaction pathways, this study investigated the combustion characteristics of NH3/N2O/O2 mixtures, with N2O as the primary oxidizer and O2 introduced as a reactive additive. Ignition delay times (IDTs) were measured in a high-pressure shock tube at 1400 – 1700 K, 5 and 10 bar, and equivalence ratios of 0.5, 1.0, and 2.0. Laminar burning velocities (LBVs) were measured in a constant-volume combustion vessel at initial temperatures of 373 and 423 K, initial pressures of 1 and 2 bar, and ϕ = 0.8 – 1.5. Moreover, an updated kinetic model has been proposed to simulate these data as well as data in the literature. Flux and sensitivity analyses have been performed, and results show that the thermal decomposition of N2O (N2O (+M) = N2 + Ö (+M)) plays a central role in promoting reactivity by supplying highly reactive O atoms, thereby altering dominant consumption pathways of key intermediates such as ṄH2. This work clarifies, at both experimental and mechanistic levels, the synergistic chemistry between NH3 and N2O, providing fundamental insights essential for accurately modeling NH3/NOx interactions and advancing the development of efficient, low-emission ammonia-based combustion technologies.

The pyrolysis and oxidation of neat Unsym-Dimethylhydrazine (UDMH), the co-incineration between UDMH and n-heptane were investigated experimentally. Experiments were carried out in a Jet-stirred reactor (JSR) with flue gas analyzer (Gasmet, FTIR DX4000) covering a temperature range of T = 500-1000 degrees C. The measurements indicate that HCN is identified as the primary nitrogen-containing product in UDMH pyrolysis, providing a basis for understanding subsequent oxidation pathways. The oxidation reaction of UDMH mainly follows the reaction path of HCN-* N2O-* NO. The addition of n-heptane significantly enhances UDMH oxidation to NOx across a wide temperature range. OH radical are generated by n-heptane oxidation to trigger UDMH oxidation through H2O2 decomposition along the pathway of HCN-* CN-* NCO-* NO at an intermediate temperature. CO is produced by n-heptane oxidation competes with O2 for N2O from UDMH oxidation during 800-1000 degrees C, thereby jointly affecting NOx emissions. The optimal process aimed at minimizing NOx emissions for co-combustion between UDMH and n-heptane was explored by response surface methodology (RSM), and the results revealed that the optimal conditions are a temperature of 618 degrees C, phi = 0.70, and R = 0.65, under which a de-NOx efficiency of 99.11 % is achieved.

Jet fuel from direct coal liquefaction (DCL) is an important alternative kerosene and represents a high-performance fuel for specific applications in civil applications. The study on its chemical positions and combustion properties is critical for the development of surrogate models and related combustion reaction mechanisms, which is valuable for promoting its usage in aeroengines. However, research on DCL-derived jet fuel is rather scarce. Herein, this work reports a systematic study on a DCL-derived jet fuel and its blends with traditional RP-3 jet fuel in two different ratios. Specifically, major physicochemical properties related to the aviation fuel airworthiness certification process are measured. Advanced two-dimensional gas chromatography (GC × GC) analysis is used to analyze the detailed chemical compositions on the DCL derived jet fuel and its blend with RP-3, which is then employed for surrogate model development. Moreover, ignition delay times (IDTs) are measured by using a heated shock-tube (ST) facility for the blended fuels over a wide range of conditions. Combustion reaction mechanisms based on the surrogate models are developed to predict the experimental measured IDTs. Finally, sensitivity analysis and rate-of-production analysis are carried out to identify the key chemical kinetics controlling the ignition characteristics. This work extends the understanding of the physicochemical properties and ignition characteristics of alternative jet fuels and should be valuable for the practical usage of DCL derived jet fuels.

Sustainable aviation fuel (SAF) is an alternative jet fuel that represents the most viable near-term solution to decarbonize the aviation industry. The airworthiness certification of SAF requires a basic understanding of its physicochemical property and combustion property. Herein, this work reports an experimental and kinetic modeling study on the physicochemical property and ignition characteristics of a SAF from Hydroprocessing Esters & Fatty acids (HEFA) and its blends with traditional RP-3 jet fuel. The physicochemical properties are analyzed, and a shock tube (ST) facility is adopted to measure the ignition delay times (IDTs) of the HEFA and its blends with RP-3. The complete group-type to component-by-component analysis of the two fuels are analyzed via two-dimensional gas chromatography (GCxGC) xGC) technique, and the results are then used to construct surrogate models. Detailed and lumped kinetic mechanisms are used to predict the measured IDTs based on the surrogate models. Finally, sensitivity analysis and rate-of-production (ROP) analysis are employed to uncover the chemical compositions on the ignition kinetics of the HEFA and its blends with RP-3. The present work should be valuable to understand the combustion chemistry of SAF and also to promote the airworthiness certification process for the large-scale usage of the studied HEFA.

To address the complexity of modeling combustion chemistry of real multi-component fuels, the Hybrid Chemistry (HyChem) approach has been developed and tested for some typical jet fuels such as Jet A, JP-8, JP10, etc. Still, the development and evolution of HyChem remain ongoing, and its potential has yet to be fully explored. The primary objective of the present study is to develop a HyChem model for describing the combustion chemistry of RP-3 while demonstrating the evolutionary understanding of the HyChem approach. In addition to the comprehensive new datasets provided by the present study as well as the development, validation, and reduction of an RP-3 HyChem model, several innovations were made regarding the HyChem development. Firstly, pyrolysis and oxidation experiments were performed in a flow reactor and utilized, sequentially, to constrain the coefficient parameters of the lumped reactions of the fuel decomposition submodel of HyChem. Meanwhile, ignition delay time and laminar flame speed measurement experiments were conducted in a shock tube and a constant-volume combustion bomb respectively, to obtain new datasets. Secondly, the species 1,3butadiene was characterized as an additional critical intermediate during the RP-3 decomposition, in addition to these identified during the Jet A decompositions, and the RP-3 HyChem model was thus proposed to be revised to contain 1,3-butadiene. Thirdly, the present study demonstrated that by taking advantage of a flow reactor system equipped with GC/microGC or GC-MS that was able to characterize a complete kinetic picture of intermediate species distribution at the millisecond reaction time scale, a reliable HyChem model could be effectively constructed. Lastly, a newly developed machine-learning-based approach DeePMR, through iterative sampling, perturbation, and deep neural network (DNN)-guided screening, was shown to effectively achieve compact reduced models with state-of-the-art accuracy. In summary, the present study revealed substantial evolutionary understanding of the HyChem approach, which would greatly improve accessibility for researchers through the selection and application of different experimental apparatus and diagnostics to explore the HyChem approach and to develop proper HyChem models, for evaluating next-generation fuels and engine applications.

Alternative jet fuel from Fischer-Tropsch (FT) synthesis represents an important kind of aviation fuel in the near future. However, the combustion properties of FT jet fuel have not been fully explored yet. Herein, this work reports an experimental and kinetic modeling study on the ignition characteristics of a coal-derived FT jet fuel. To facilitate its usage as a "drop-in" fuel in current aircraft and infrastructure, a blended fuel of the present FT fuel with a traditional RP-3 jet fuel with relatively high aromatic hydrocarbons is also prepared and studied. Specifically, a shock tube facility is employed to measure the ignition delay times (IDTs) of the FT, RP-3, and the blended jet fuels under the combustion conditions, i.e., temperature ranging from 1000-1800 K, pressure at 3 and 10 bar, equivalence ratio at 0.5, 1.0, and 2.0. Two-dimensional gas chromatography (GC x GC) analysis is adopted to determine the chemical compositions of the FT and RP-3 jet fuels, which is then used to aid the development of surrogate models. Most importantly, the contemporary combustion chemical kinetic mechanism via detailed generation, automatic generation, lumping, decoupling and HyChem methods are employed to model the IDTs, and the mechanism reproducibility of these mechanisms are systematically compared. The present work should be valuable to understand the chemical structure effect on alternative jet fuels and also provides important information for the development of different kinds of combustion kinetic mechanisms.

It is necessary for gasoline surrogate models to simulate the effect of NOx addition on fuel auto-ignition behavior, as NOx can affect engine combustion via exhaust gas recirculation (EGR). Toluene is often used as a representative aromatic component in gasoline surrogate models, and hence it is important to investigate the effect of NOx addition on its auto-ignition behavior and to fully understand the interaction chemistry between toluene and NOx. In this paper, high-pressure shock tubes and a rapid compression machine are used to measure the ignition delay times (IDTs) of toluene in 'air' mixtures with and without the addition of nitrogen dioxide (NO2), at a pressure of 20 atm and at temperatures in the range 600-1400 K. The IDTs of n-heptane, iso-octane and a mixture of toluene/n-heptane/iso-octane are measured at the same conditions for comparison. The experimental results show that the auto-ignition behavior of toluene exhibits significantly different sensitivity to NO2 addition compared to n-heptane and iso-octane. NO2 significantly promotes the reactivity of toluene at low temperatures (600-1000 K), in which the IDTs decreased by two orders of magnitude when 1000 ppm of NO2 is added, whereas there is an order of magnitude decrease with the addition of 200 ppm NO2. The promoting effect of NO2 on toluene oxidation reduces significantly at temperatures above 1000 K. The experimental results also show that NO2 addition exhibits a slight promoting effect on the reactivity of n-heptane and iso-octane at temperatures above 750 K at the conditions studied. A kinetic model is proposed based on C3MechV3.3 in which the interaction chemistry between these gasoline surrogates and NOx is updated. The proposed kinetic model can simulate well the effect of NO2 addition on the auto-ignition behavior of these surrogates. Flux and sensitivity analyses are performed to highlight the important interaction reaction pathways.

Al is widely used in solid propellants for its high energy density. (C6H14N2)[NH4(ClO4)3](DAP-4), a novel energetic material, exhibits excellent detonation performance, thermal stability, oxidizing capacity, and cost efficiency, making it a promising high-energy oxidizer. This study investigated the ignition and combustion properties of DAP-4/nano-Al mixtures. DAP-4 was synthesized via a one-pot molecular self-assembly strategy, and mixtures with varying Al ratios (10%-30%) were prepared through mechanical mixing. X-ray diffraction (XRD) confirmed that the mixed powders retained their original crystalline structures without the formation of new phases. Scanning electron microscopy (SEM) revealed that nano-Al particles adhered effectively to DAP-4 surfaces, with higher Al content increasing the particle coverage. Elemental mapping and EDS were used to further characterize the surface morphology changes. Thermogravimetry-Differential Scanning Calorimetry(TG-DSC) indicated good compatibility between DAP-4 and nano-Al, with minimal mutual interference during thermal decomposition. Ignition experiments were conducted in a shock tube under temperatures (2200-3100 K) and pressures (0.1 and 0.5 MPa). The results showed that in the DAP-4/nano-Al mixtures, an increase in the Al fraction caused a decrease in the ignition delay time and an increase in the burn time. Simultaneously, the reaction in the presence of Al changed qualitatively, as is apparent from the changed activation energies. Compared to the combustion of neat DAP-4, both the ignition delay and burn times could be longer or shorter, depending on the Al fraction. This study demonstrated that the addition of nano-Al effectively enhanced DAP-4 combustion. In practice, DAP-4's ignition and combustion can be controlled by adjusting the nano-Al mass fraction.

The auto-ignition and flame propagation behaviors of RP-3 kerosene/nitrous oxide (N2O) is crucial for developing chemical kinetic models and evaluating their compatibility in current liquid rocket engines. Herein, this study employs a high-pressure shock tube (HPST) to measure the ignition delay times (IDTs) of Chinese RP-3 kerosene in N2O/N2 under a wide range of combustion conditions: equivalence ratios of 0.5, 1.0, and 2.0; pressures of 5, 10, and 20 bar; temperatures ranging from 1300 to 1950 K. The effects of temperature, pressure, and equivalence ratio on IDTs are examined. Additionally, laminar burning velocities (LBVs) are measured in a spherical vessel for an unburned RP-3 kerosene/N2O/N2 mixture with initial temperature of 423 K and initial pressure of 1 bar To enhance understanding the underlying chemistry, a multi-component RP-3 kerosene surrogate model (65 % n-dodecane / 20 % 1,3,5-trimethylcyclohexane / 15 % n-propylbenzene in mass fraction) is proposed and used to simulate the experimental data. A detailed chemical kinetic mechanism is constructed and further reduced through the revised-direct relation graph (Revised-DRG) method with a multi-stage reduction strategy to derive a compact skeletal mechanism comprising 79 species and 451 reactions. Comparisons between the predictions via the skeletal mechanism and experimental data demonstrate acceptable performance in reproducing the measured IDTs and LBVs. Sensitivity analysis is conducted to identify key reactions controlling ignition and flame propagation characteristics. This comprehensive experimental dataset and the developed kinetic models significantly enhance our understanding of RP-3 kerosene/nitrous oxide combustion characteristics, contributing valuable insights to the field of rocket propulsion.

This paper reports a comparative study on the high temperature pyrolysis characteristics of three C9H12 isomers, including n-propylbenzene (PBZ), 1,3,5-trimethylbenzene (T135MBZ), and 1,2,4-trimethylbenzene (T124MBZ), via single-pulse shock tube (SPST) experiments and kinetic simulations. The SPST experiments were conducted in the temperature range of 1100–1700 K, at pressures of 10 bar and 15 bar, with a fixed fuel concentration of 200 ppm. The reaction time was approximately 1.8 ms for all of the experiments. The distributions of the pyrolysis products were quantitatively analyzed as functions of pressure and temperature. A detailed kinetic mechanism was used to simulate the experimental results, and it is demonstrated that the mechanism can capture the pyrolysis characteristics reasonably well. Both experimental and simulation results reveal that PBZ exhibits higher fuel reactivity than T124MBZ and T135MBZ under the studied conditions. Pyrolysis of all three C9H12 isomers generates key soot precursors, including acetylene and benzene. Sensitivity and rate-of-production (ROP) analyses indicate similar primary pyrolysis pathways. The benzyl radical is first formed through the dehydrogenation reaction and then it undergoes a series of decomposition reactions leading to the detected small hydrocarbon species. This study not only provides an in-depth understanding of the high temperature pyrolysis characteristics of the three C9H12 isomers, but also provides essential validation data for the development and optimization of chemical kinetic mechanisms for alkyl aromatic hydrocarbons.