Investigating the relationship between the distribution of light and heavy fractions in thermal dissolution soluble portions (SPs) and the composition and structural characteristics of raw coal is crucial for elucidating the depolymerization mechanisms of soluble organic matter in coal. In this study, fourteen medium and low-rank coals from China were thermally dissolved at 320 degrees C using an isometric toluene/methanol mixture as the solvent. The correlations between the relative contents of three fractions (light oil, asphaltenes, and preasphaltenes) in the SPs and the composition and structural characteristics of the raw coals were systematically examined. The results show that the SP yield is positively correlated with the volatile matter content of raw coal. Higher H/C and O/C atomic ratios in the coal samples are associated with increased yields of both SPs and light oil; however, as these ratios increase, the proportion of light oil in the SPs gradually decreases. Fourier transform infrared spectroscopy (FT-IR) analysis further reveals that the proportion of light oil in the SPs increases with the aromaticity of raw coal, but decreases with longer aliphatic side chains, suggesting that extended aliphatic side chains hinder the formation of light oil during thermal dissolution. Additionally, as the oxygen enrichment coefficient increases, the proportion of light oil first decreases and then rises. This study provides important theoretical insight into the depolymerization mechanisms of organic species in coal.

Pyrolysis of cellulose to levoglucosan is typically limited by secondary reactions that degrade the primary products. Here, we report a strategy that combines vacuum pyrolysis with rapid quenching of volatiles to suppress secondary reactions and achieve high yields of levoglucosan. alpha-Cellulose with a particle size of similar to 50 & micro;m was rapidly inserted into the hot zone of a fixed-bed reactor for fast pyrolysis over 350-500 degrees C. Under the optimum conditions of 5 kPa (absolute pressure) and 425 degrees C, the yield of levoglucosan, as quantitatively determined by high-performance liquid chromatography, reached 60.8 wt% on a dry cellulose basis, corresponding to a selectivity of 86.0% in bio-oil. Gas chromatography/mass spectrometry analysis revealed that total anhydrosugars comprised 97% of the bio-oil based on peak area percentage, while the formation of light oxygenates and solid coke was negligible. This catalyst-free pyrolytic strategy offers a viable route for the highly selective production of levoglucosan from cellulose.

Deep hydrogenation of coal-derived naphthalene oil into high-energy–density fuels faces severe constraints from sulfur poisoning of noble metal catalysts. A confined Pd@HZSM-5 catalyst synthesized via a one-pot hydrothermal strategy effectively decouples physical confinement from hydrogen spillover. Systematic investigations elucidate a metal–acid synergistic mechanism wherein framework Brønsted acid sites function as essential acceptors for hydrogen spilled from encapsulated ultrafine Pd nanoclusters. The optimized architecture physically blocks bulky sulfur poisons via molecular sieving while sustaining hydrogenation through efficient ultrashort-range spillover. Consequently, Pd@HZSM-5 exhibits superior resilience by retaining a naphthalene conversion of 32.36% with 1000 ppm dibenzothiophene present, a value approximately 2.5 times higher than that of conventional impregnated catalysts. These findings offer design principles linking metal–acid distance to hydrogen utilization efficiency for bifunctional catalysts tailored for upgrading sulfur-rich feedstocks.

Improving the catalytic efficiency and catalyst life of Pt/Al2O3 catalyst for methylcyclohexane dehydrogenation is of great significance for the study of organic liquid hydrogen storage. In this work, the promotion effects of Ga and Ce on the substantial improvement of catalytic stability and activity over the Pt/Al2O3 during the methylcyclohexane dehydrogenation were investigated. The catalyst with optimizing Ga and Ce loading (1.5 wt%) exhibits similar to 99.76 % selectivity and H-2 evolution rate of 2102 mol/g(Pt)/min at 300 degrees C. In 100 h long-time reaction, the conversion of methylcyclohexane remains around 75 % with no significant decrease. The characterization results show that introducing proper amount of Ga and Ce helps Ga3+ cations incorporate into the lattice structure of CeO2 that increase concentration of oxygen vacancies and CeO2 reducibility in the catalyst, which boost the capability of methylcyclohexane dehydrogenation and tolerance for coke formation. Thus, the excellent stability and activity are achieved over the GaCe-modified catalyst. This study may share new light on the rational construction of highly efficient Pt-based catalysts for methylcyclohexane dehydrogenation.

Dimethyl oxalate (DMO) hydrogenation is a very useful industrial reaction because a series of bulk chemicals, such as methyl glycolate (MG), ethylene glycol (EG), methyl acetate (MA) and ethanol can be produced by precisely tailoring the hydrogenation extent. However, tailoring the product distribution still remains a big challenge because it is a stepwise hydrogenation reaction, which largely depends on the catalyst and reaction temperature. Herein, the products MG and MA can be synthesized with excellent conversion (>90%) and selectivity (>90%) over Ni3P with a novel dendritic porous SiO2 structure (Ni3P/DPS) by only changing the reaction temperature. Moreover, the MG selectivity can be maintained above 90% in a wide reaction temperature range (200-280 degrees C), which has not been observed with the known catalyst. Meanwhile, the MA selectivity is higher than 90% and only about 4% of EG selectivity can be obtained even at 360 degrees C. Compared with the traditional DMO hydrogenation catalyst, Ni3P/DPS exhibits superior stability at high temperatures (340 degrees C) for 300 h without agglomerate deactivation. The precise control of DMO hydrogenation reaction pathways is further confirmed by DFT calculations and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).

The methylcyclohexane (MCH) cycle, a promising liquid organic hydrogen carrier, has garnered significant attention owing its low cost and excellent compatibility with the existing petrochemical transportation infrastructure. Pt cluster-based catalysts are well-recognized candidates for MCH dehydrogenation. However, precise geometric modulation of Pt clusters to overcome the inherent limitation of catalyst performance remains a critical challenge. In this study, we successfully modulated the geometric structure of Pt cluster active sites through a silica coating strategy. The silica layer preferentially covers the low-coordination sites (i.e., the corner and edge sites) of Pt, which effectively suppresses deep dehydrogenation and weakens the adsorption of the toluene. The optimized 1.5Si@Pt/Al2O3 catalyst achieved an outstanding MCH conversion of 95% at 300 oC, accompanied by toluene selectivity 99.88%. Moreover, after three cycles of regeneration, the 1.5Si@Pt/Al2O3 catalyst retained catalytic activity comparable to that of the fresh catalyst, as the silica layer inhibits metal sintering and leaching during the regeneration process. This work highlights the importance of engineering the geometric structure of Pt active sites and provides an effective strategy for developing highly efficient and recyclable catalysts for MCH dehydrogenation.

This study shows that in situ-reduced Co 3 O 4 catalyzes lignin HDO, yielding cyclohexane and cyclohexanol. Post-reaction calcination removes coke and restores the structure, providing strong stability and anti-coking performance, solving the issue of catalyst deactivation in lignin HDO.

Ni-based catalysts have been reported effective for improving CO2 methanation, but drawbacks of common catalyst like easily sintering limited their long-term application. This work evaluated the influence of representative M metals (La, Ce, Ru, and Fe) on the activity of Ni-based Mg-Al mixed oxides (MAO) in CO2 methanation. Among them, the Ni-Ce/MAO catalyst demonstrated superior activity, achieving 83.0% CO2 conversion and 98.4% CH4 selectivity at 350 degrees C, alongside excellent long-term stability. The characterization results suggested that the abundant oxygen vacancy, high amount of medium basic sites, small Ni particle size, great reducibility in Ni-Ce/MAO were proved as the main origins for the improvement of the CO2 methanation at low temperature. The difference in reaction intermediates and reaction pathways together with the coordination environment difference of obtained Ni-M/MAO catalysts were carefully analyzed by in-situ diffuse reflectance infrared Fourier-transform spectroscopy and X-ray absorption spectroscopy.

Methyl-butyl ketone (MBK), a representative long-linear ketone with six-carbon atoms, is identified as a promising second biofuel. To better understand the decomposition chemistry of MBK, experiments were performed at 1.0 atm, 723-1025 K in a jet stirred reactor. Over ten stable intermediates and products are detected, including C1-C4 hydrocarbons and oxygenated species. A detailed kinetic mechanism is developed with reasonably prediction of speciation profiles newly reported in this work. The rate of production and sensitivity analysis show that MBK primarily decomposes via H-abstractions by H and CH3 attacking to form five distinct MBKyl at temperatures below 900 K, whereas the contribution of unimolecular dissociations are increase at elevated temperatures. Among them, the H-abstractions at C(3)-position near the carbonyl functional group have the fastest rate constant with the highest contribution. These MBKyls subsequently undergo beta-scissions by C-C or C-H bonds, isomerizations by intramolecular H-transfers and addition-eliminations with H to generate a series of intermediates and products. Furthermore, the effects of differences in chain-lengths and cyclic/acyclic structures of ketones on their pyrolysis intrinsic reactivity and production formation are evaluated. By comparing four methyl-ketones with C1-C4 alkyl chains at the C2-site, it is concluded that longer alkyl-chains enhance pyrolysis reactivities, accompanied by promoting the growth of C2-C4 alkenes and inhibiting CO formation. For two sixmembered acyclic/cyclic ketones, MBK exhibits higher pyrolysis reactivity than cyclohexanone, and formed respective fuel radicals further influence products formation. Notably, ring-opening dissociations of cyclohexanone radicals yield abundant C3/C4 intermediates, enhancing aromatic precursors formation. In contrast, chaincleavages of MBK-derived radicals favor to increase mono-olefin production.

Selective hydrogenolysis of C-O bonds in lignin is widely regarded as the most promising strategy for generating high-value chemicals and clean liquid fuels. Ni-Ru bimetallic catalyst supported on solid superacid was successfully synthesized and applied to the cleavage of C-O bonds in diphenyl ether (DPE) and alkali lignin. The catalytic hydrogenolysis of DPE over a 10%Ni-0.5%Ru-S2O8 2-/ZrO2 catalyst produced 88.0% cyclohexanol. Additionally, 10%Ni-0.5%Ru-S2O8 2-/ZrO2 catalyzed the depolymerization of alkali lignin in high yields of phenolic compounds, primarily including guaiacol and methoxyphenol. The synergistic effect between Ni and Ru promoted electron transfer from Ni to Ru. The incorporation of Ru improved the dispersion of Ni and reduced the average particle size of metallic Ni. The strong acidity of the solid superacid support provided abundant acidic sites, facilitating hydrogen atom adsorption and thereby promoting C-O bonds cleavage.

Catalytic pyrolysis as an important pathway for the production of sustainable chemicals and fuels from biomass. However, it is still a huge challenge to significantly improve the yield of light aromatics by adjusting the structure of ZSM-5 zeolite and to fully understand its catalytic mechanism. Here, the directional preparation of ZSM-5 nanosheets with controllable b-axis thickness was achieved by controlling the amount of silicalite-1 added during the hydrothermal synthesis process. Characterization results demonstrate that the reduction in b-axis thickness greatly enhances the mass transfer process of the zeolite while enhancing the accessibility of acidic sites, thereby promoting the catalytic conversion of biomass pyrolysis volatiles to aromatic. The yield of light aromatic hydrocarbons in bio-oil is substantial increased, the bio-oil of 20-NCZ5 had the highest aromatic content with a yield of 97.1% and a yield of 135 mg/g, achieving efficient catalytic upgrading of bio-oil. Highly b-axis-oriented ZSM-5 nanosheets provide a new approach for efficient biomass utilization. Furthermore, this zeolite holds promise for broader applications in the catalytic conversion of various energy sources.

Perfluoropolyether (PFPE) lubricants play a significant role in the aerospace industry due to their outstanding chemical stability, thermal stability and anti-wear properties, however, their decomposition behavior has not been revealed fully. Herein, the decomposition mechanism and performance characteristics of four types of PFPE lubricants are investigated thoroughly by means of in situ heating fourier-transform infrared spectroscopy (in situ FTIR) and pyrolysis-gas chromatography/mass spectrometry (Py-GCMS). The results show that the specific sequence of antioxidant ability of PFPE is Fomblin Z03>Fomblin LC80>Fomblin M03tiFomblin Y04. Moreover, metals can accelerate the oxidation of PFPE lubricants, generating acids, esters and anhydrides, resulting in an increase of acid value from 0.0025 mg KOH/g to 0.0109 mg KOH/g and 7.7 per cent increase in kinematic viscosity for Fomblin M03 after oxidation in 260 degrees C for 72 h. This work provides a technical scheme for the safe use of perfluoroalkylpolyether lubricants and promotes the research and application of new-generation ultrahigh-temperature aviation engine lubricants.

This study investigated the impact of phosphorus, organic matter in coal and calcium on the agglomeration mechanism and ash transformation for co-gasification of potassium-salt-impregnated pine wood and a bituminous coal. A lab-scale fixed-bed reactor was utilized to perform co-gasification experiments under a steam atmosphere and the samples were analyzed with several characterization techniques. The results show that potassium aluminosilicates generally dominate the ash but calcite addition inhibits the formation of potassium aluminosilicates, especially for biomass rich in potassium chloride. For biomass rich in phosphorus, the addition of calcite to a certain concentration changes the agglomeration mechanism from molten-potassium-phosphate-induced to molten-potassium-silicate-induced. The removal of organic matter in coal also inhibits the formation of potassium aluminosilicates, especially for biomass rich in potassium chloride. This study reveals the potassium-occurrence-form-dependent regulatory rule of ash composition and the dynamic transformation pathway of agglomeration mechanism, providing key theoretical support and precise regulation ideas for solving the agglomeration problem in biomass utilization.

The complex composition of bio-oil necessitates advanced separation strategies for its valorization. This work reports the application of biochar as a sustainable and structure-tunable stationary phase in column chromatography for the efficient fractionation of bio-oil. Biochars with distinctly different properties were engineered through pyrolysis of bamboo at 400 degrees C (bsC-40 0) and 700 degrees C (bsC-70 0). Comprehensive characterization confirmed that bsC-70 0 possessed a highly aromatized and hydrophobic surface with a well-developed porous network, while bsC-40 0 retained a polar and oxygenfunctionalized surface. Their chromatographic performance revealed a fundamental structure-function relationship, as evidenced by the strong retention of sugars on the polar surface of bsC-40 0 via hydrogen-bonding interactions, which necessitated the use of aggressive solvents for elution. In contrast, bsC-70 0 exhibited exceptional affinity for phenolics via pi-pi stacking, while facilitating the early and efficient elution of sugars with moderately polar solvents due to its non-polar chemistry. This study establishes pyrolysis temperature as a critical design parameter for tailoring biochar selectivity, positioning it as a versatile stationary phase for targeting specific compound families within complex mixtures and advancing integrated biorefinery concepts. (c) 2026 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

The hydrolysis of the C-O bonds in lignin-derived compounds represents a significant pathway for the synthesis of oxygen-containing chemicals. The development of a support with hydrophilic properties represents a crucial step in this reaction. Glucose is a particularly suitable precursor for the preparation of hydrophilic-activated carbon due to its abundance of oxygen functional groups. In this study, Ni/HACs, prepared by using glucose, were employed. The high specific surface area of Ni/HAC-6-7 is conducive to the dispersion of Ni, resulting in the smallest metal particle size and the highest Ni0 concentration. Additionally, its favorable hydrophilicity facilitates the entry of water molecules, which are essential for the reaction, into the reactive sites. Under mild conditions (180 degrees C and 1 MPa of H2), complete conversion of diphenyl ether was observed, along with a cyclohexanol selectivity of 63.7%. This study provides a strategy for the development of a lignin-directed hydrolysis process.

Coking substance in ester aviation lubricating oil has a great effect on the flight safety of aircraft, however its origin and forming mechanism is complicated and controversial. Herein, the coking mechanism of ester lubricating oil is investigated deeply based on the crankcase simulation test and thin film oxidation evaluation. Besides, its structural and compositional change is also detected through in situ thermal infrared spectroscopy and gas chromatography-mass spectrometer analysis. The results reveal that oil film can be detected when the oxidation time extends to 40.31 min during the thin film oxidation test at 613 K. Whereas, the weight of carbonaceous deposits increases obviously until the oxidation time extends to 4 h in thick oil oxidation at 613 K. The thin film oxidation is evidently identified as the origin for the formation of coking substance, and its formation process involves the orderly breakage of C-O and C-C bands, the formation, polymerization and carbonization of RCOO center dot and peroxides. More importantly, the tribological performance of ester lubricating oil before and after oxidation and the real characteristics of coking substance are also discussed contrastively, which providing a foundation for safely using this type of lubricating oil.

Lignin, due to its structural rigidity, tends to form coke deposits during catalytic hydrodeoxygenation (HDO), causing catalyst deactivation, and eliminating coke to restore performance is challenging. In this study, Co3O4 shows excellent HDO performance toward lignin model dimers, with high selectivity for demethoxylation and deethoxylation under mild conditions via a one-step strategy integrating in situ reduction and HDO, thereby enabling lignin HDO. At 240 degrees C, 2 MPa, and 20 h, lignin achieved a 73% liquid yield, with 64%, 30%, and 6% selectivities to alkanes, alcohols, and phenols. This is attributed to Co3O4's high Co-O bond energy, dominant (220) crystal plane exposure, and high Co3+/Co2+ ratio, facilitating in situ reduction to metallic cobalt active sites. Coke on Co3O4 can be removed by calcination to restore performance, with 90% of the initial liquid yield retained after five cycles. This low-cost commercial non-noble metal Co3O4 enhances the economic feasibility of lignin's high-value utilization.

Research on pressurized methane dry reforming (DRM) is of great significance for the integration with downstream F-T synthesis processes and reducing gas compression costs. However, the increase in pressure leads to severe coking, which limits the stable operation of the process. Developing Co-based bimetallic catalysts doped with a small amount of noble metals is one of the important approaches to improving the catalysts' coking resistance and catalytic performance, thereby alleviating this issue. In this work, a carbon-supported Co-Ir bimetallic catalyst doped with 0.2 wt% Ir (denoted as Co-0.2Ir/C) was developed. Structural characterizations confirmed the formation of Co-Ir alloy, with the metal particles on the catalyst being highly dispersed and having an average particle size of 4.82 nm. Under the reaction conditions of 800 degrees C, 0.5 MPa, and 30,000 mL gcat -1 h- 1, the incorporation of Ir effectively enhanced the initial catalytic activity of the catalyst and achieved stable operation for 100 h, with final CH4 and CO2 conversion reaching 73.9 % and 82.8 %, respectively. In addition, this study focused on the structural changes of the catalyst during the induction period, confirming the dynamic evolution laws of metal particle redispersion and amorphous carbon graphitization. These findings explain the dynamic variation phenomenon where the conversion of CH4 and CO2 first increased significantly and then gradually stabilized during the reaction. This study provides certain guiding significance for the development of relatively low-cost carbon-supported metal catalysts, the realization of stable operation of DRM under pressurized conditions, and the clarification of the structure-activity relationship of such catalysts in the DRM reaction.

The effects of dust, copper particles, and iron particles on the high-temperature oxidative degradation behavior of aviation lubricating oil were systematically examined, and the high-temperature catalytic oxidation effects of single-particle and mixed-particle systems on the lubricating oil were further analyzed, respectively. Gas chromatography/mass spectrometry analysis results indicated that significant differences exist in the catalytic oxidation activity of particles toward lubricating oils, with the activity ranking in the descending order of copper particles > iron particles > dust. Notably, following oxidation by both metal and dust particles, the acid value, particle size, and viscosity of the oil sample exhibit a significant synergistic catalytic effect, even exceeding those of the oil sample oxidized by the same amount of metal particles. Specifically, relative to the pristine oil, the oil oxidized with 5 mg of copper particles and 5 mg of dust exhibits respective increases of 213.3%, 316.11%, and 661.43% in the aforementioned properties. This variation is attributed to the physical adsorption and chemical reactions between dust and antioxidants during oxidation, which deplete antioxidants and thereby exacerbate oil oxidation. Furthermore, this study further elucidates the potential synergistic oxidation mechanism induced by metal particles and dust particles.

To overcome the issue of constrained mass transfer efficiency and conversion capacity of conventional commercial ZSM-5 in biomass pyrolysis for aromatics production, Zn-doped nano-ZSM-5 catalysts were prepared using Dry Gel Conversion-Steam Assisted Crystallization (DGC-SAD) method. This synthesis strategy concurrently modulated the particle size of ZSM-5 and incorporated new active sites, which effectively increased the yield of the target product and inhibited coke deposition. The variation of TPAOH content revealed optimal catalysts as DZ5-12 (synthesized by the DGC-SAD) and Z5-16 (synthesized by the hydrothermal), demonstrating the DGC-SAD method 's advantage in TPAOH utilization efficiency. Compared with the hydrothermal synthesis method, the nano-ZSM-5 synthesized by the DGC-SAD method has a larger mesoporous specific surface area and smaller grain size, which improves the mass transfer efficiency, promotes the diffusion of macromolecules during the reaction process, and avoids the coke deposition due to the accumulation of macromolecule oxygencontaining compounds while increasing the reaction products. Moreover, the DGC-SAD method of Zn doping effectively avoids the loss of Zn during the synthesis process and provides more ZnOH+ active sites for the zeolite, and its larger mesoporous specific surface area also improves the accessibility of the active sites. The catalytic evaluation demonstrated that the catalytic pyrolysis of cellulose using ZnDZ5-12 resulted in the highest light aromatic yield of 174.68 mg/g and the lowest coke yield of 7.7 %.