Transfer of reactive oxygen species triggered by soil organic matter deactivation enhanced the oriented oxidation of petroleum hydrocarbons

Multi-step hydrocarbon oxidation during thermochemical sulfate reduction and its impact on hydrocarbon evolution

Full genome sequences of two strains of Pseudomonas stutzeri isolated from oil reservoirs and their adaptation mechanisms to harsh environments

Abstract. Bicyclic peroxy radicals (BPRs) from aromatics hydrocarbons oxidation play increasingly recognized roles in the formation of secondary air pollutants. However, their reaction mechanisms remain poorly constrained, largely due to the lack of direct measurement techniques. In this study, we developed a method for quantitative measurement of BPRs using an iodide chemical ionization mass spectrometer (Vocus AIM). Following instrument optimization, the sensitivity for BPRs reached 0.3–0.6 ncps pptv−1, with a detection limit of ∼ 1 pptv and an uncertainty of ∼ 41 %. Our flow reactor experiments revealed that the bicyclic pathway dominates the OH-initiated oxidation of aromatics under low-NOx conditions, accounting for 57.0 % and 69.5 % of the oxidation products of toluene and m-xylene, respectively. Comparative analysis further demonstrated that conventional product-yield-based approaches underestimate the branching ratio of the bicyclic pathway by 4 %–9 % relative to direct BPR quantification. This discrepancy suggests the presence of unaccounted reaction channels in current chemical mechanisms, even when autoxidation and accretion reactions are considered. By directly quantifying BPRs, this study provides new insights into the atmospheric oxidation of aromatics and highlights the need for further mechanistic investigation. Moreover, the reaction-pathway-controlled quantification approach proposed here effectively reduces the challenges associated with measuring functionalized RO2 radicals and demonstrates strong potential for sensitive, speciated RO2 detection using Vocus AIM in both laboratory and ambient environments.

The activation of dioxygen by organoplatinum(II) complexes in the presence of protic reagents is shown to occur by a mechanism that is a form of proton coupled electron transfer. The establishment of the mechanism, after false starts, and the current state of knowledge are described. The research is relevant to the catalytic oxidation of hydrocarbons by platinum metal or platinum complex catalysts and to the oxygen reduction reaction in biology and fuel cell technology.

Enhancement of soil organic matter stability cross-linked with aluminium drove the reallocation of ROSs for the directional oxidation of petroleum hydrocarbons.

The effects of traditional diesel aftertreatment systems on gaseous emission reductions from ammonia/diesel dual-fuel engine.

Over the last decade, there have been significant advances in our understanding of anaerobic hydrocarbon oxidation in archaea. However, the ability to oxidise hydrocarbons aerobically has been described in bacteria but not yet in archaea. Here, we provide evidence supporting potential aerobic hydrocarbon oxidation ability in archaea belonging to a novel order within the class Syntropharchaeia, which we propose to name Candidatus ‘Aerarchaeales’. This order is represented by six metagenome-assembled genomes (MAGs) spanning three genera that are found in terrestrial and marine ecosystems. In particular, MAGs belonging to a newly defined genus, Ca. ‘Aerovita’, encode a copper monooxygenase complex with homology to bacterial hydrocarbon monooxygenases. The presence of genes encoding other oxygen-dependent enzymes, such as haem-copper oxygen reductase, indicates that Ca. ‘Aerovita’ may be capable of aerobic respiration. Our findings suggest that horizontal gene transfer between archaeal and bacterial domains facilitated the evolution of aerobic hydrocarbon-oxidizing archaea.

We report a novel electrocatalytic approach that couples water oxidation with toluene oxidation in wet DMF or DMSO electrolyte. Electrocatalytic oxidation of water, a sustainable oxygen atom source, favored hydroxyl (·̇OH) radical formation over hydrogen peroxide and oxygen evolution because the organic solvent molecules suppressed O-O bond formation via hydrogen bonding. Water oxidation was catalyzed by laser-synthesized [NiFe]-(OH)2 nanosheets supported on hydrophilic carbon fiber paper anodes, enhancing water oxidation activity and toluene oxygenation efficiency. Under optimized conditions in wet DMF electrolyte, toluene oxidation achieved 100% selectivity for benzyl alcohol at an unprecedented conversion yield of 87%. In wet DMSO electrolyte, 100% selectivity for benzyl alcohol was obtained, albeit with significantly lower conversion yield. Combined experimental and computational results reveal a new mechanistic pathway, based on electrocatalytic water oxidation to ·OH radicals and protons. Protonation of DMF enabled the formation of H+-DMF-·OH radical complexes stabilized by hydrogen bonding among the radical, protonated and unprotonated DMF molecules, and water. This radical stabilization played a crucial role in promoting benzyl alcohol production. In contrast, DMSO consumed ·OH radicals to form methanesulfinic acid, limiting benzyl alcohol generation. The wet organic solvent environment additionally prevented overoxidation beyond the alcohol by stabilizing radical intermediates through hydrogen bonding networks, effectively arresting the reaction after the first oxygenation. Likewise, benzyl alcohol oxidation yielded benzaldehyde, with no overoxidation to benzoic acid. Our findings establish fundamental design principles for selective hydrocarbon oxidations by leveraging solvent-mediated interactions, with broad implications for sustainable chemical synthesis.

Carbon nanotubeshave gained significant interest incatalysis(as catalysts and catalyst supports) for hydrocarbon oxidation processes.In this study, pristine multiwalled carbon nanotubes and copper­(II)functionalized multiwalled carbon nanotubes were coated with [bmim]cationic ionic liquids (ILs) containing dissolved N-hydroxyphthalimide (NHPI) to produce novel SILP and SCILL-SILP hybridcatalytic systems, respectively (SILP: supported ionic liquid phaseand SCILL: solid catalyst with an ionic liquid layer). The catalyticactivities of the produced systems were investigated for the solvent-freeoxidation of ethylbenzene (EB) (80 °C, 0.1 MPa, 6 h) using molecularoxygen as a green oxidant. Among the SILP systems, the 1-butyl-3-methylimidazoliumchloride ([bmim]­[Cl])-based SILP system exhibited the highest conversionof EB (12.2 ± 3.1%) with enhanced selectivity (84.1 ± 11.4%)toward acetophenone (AcPO). The catalytic activity of the SILP systemincreased with increasing lipophilicity of the alkyl group in theIL cation. Conversely, among the SCILL-SILP systems, the highest conversionof EB (22.6 ± 1.2%) was achieved using 1-butyl-3-methylimidazoliumbis­(trifluoromethylsulfonyl)­imide ([bmim]­[NTf2]) as theIL phase. Recyclability and reusability studies showed that the catalyticactivities of the SILP and SCILL-SILP hybrid systems generally decreasedin the subsequent cycles, except for 1-butyl-3-methylimidazolium octylsulfate ([bmim]­[OcOSO3])-based catalytic systems, whichwere relatively stable.

Selective oxidation of hydrocarbon with NHPI/facet-mediated α-Fe2O3 under the visible-light at ambient temperature

Derivation and application of autoignition-based simplified kinetic models of hydrocarbon oxidation for fire simulations

Petroleum-fuelled methanogenesis and microbial hydrocarbon oxidation at an abandoned oil well

Lipid nanoparticles are a versatile class of clinically approved drug delivery vehicles, particularly for nucleic acid cargoes. Despite this, these materials often suffer from instability issues that limit shelf-life or necessitate storage at ultra-cold temperatures. Herein, we demonstrate that the oxidation of unsaturated hydrocarbons within ionizable lipid tails results in the production of a dienone species that changes the conformation of the lipid tail and generates an electrophilic degradant that reacts with neighboring siRNA cargoes to produce siRNA-lipid adducts. This mechanism highlights the interplay between lipid degradation, colloidal instability, RNA-lipid adduct formation, and loss of bioactivity. In this work, we show that revised drug product matrixes, including mildly acidic, histidine-containing formulations, can improve room temperature stability of siRNA-lipid nanoparticles by mitigating these oxidative degradation mechanisms.

Selective hydrocarbon oxidation processes are central in fine and commodity chemical production and are sensitive to the nature of the active metal sites and their surrounding coordination environment. Isometallic Fe-based carboxylate MOFs (MIL-100, MIL-101, and NH2-MIL-101) are employed to elucidate how Fe coordination environments and framework topology influence a probe aryl (styrene) oxidation mediated by hydrogen peroxide (H2O2). MIL-101 shows the highest oxygenate production turnover rates, as normalized by in situ thiophene titrations, followed by NH2-MIL-101 and MIL-100. Post reaction ex situ Mössbauer spectroscopy elucidates Fe(II) formation under reaction conditions that underpin increased oxygenate production turnover rates; this Fe(II) formation was enabled by the reductive elimination of halide capping ligands unique to the MIL-101 family but not present in MIL-100 that only contains hydroxyls. Defect undercoordinated Fe sites promote unproductive H2O2 decomposition and secondary oxygenate formation but do not perturb primary oxygenate selectivities. Conversely, stabilizing hydrogen-bonding interactions between N-H donors and postulated benzaldehyde metallocycle transition state structures confer NH2-MIL-101 100% selectivity for the primary oxygenate product benzaldehyde over styrene oxide at differential styrene conversions (<3%) compared to a maximum of 59% for MIL-101. Although a fraction of linker amine moieties oxidize to form nitro groups within NH2-MIL-101, Fe leaching, identified as a contributor to catalyst deactivation for all frameworks, is reduced. Overall, this work showcases how seemingly subtle changes and perturbations to the coordination environments local to metal sites influence the observed reactivity, selectivity, and stability for oxidative (and other) transformations within MOF-catalyzed reaction systems throughout their lifetimes.

In situ chemical oxidation (ISCO) is a highly effective remediation technique for the complete mineralization of organically contaminated soil. This study focused on the oxidative remediation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil using a composite oxidant system composed of monohydrated citric acid (CA) chelated with ferrous sulfate heptahydrate (FS) and activated sodium persulfate (PS) and sodium percarbonate (SPC). The effects of four individual factors-PS dosage, SPC dosage, FS addition, and CA addition-on PAH degradation were examined. Optimization of the test conditions using response surface methodology demonstrated that the dual oxidant system significantly increased the degradation rate of PAHs. The optimal process conditions were identified as follows: PS concentration of 52.66g/kg, SPC concentration of 30.24g/kg, FS concentration of 47.71g/kg, CA concentration of 6.80g/kg, a water-soil ratio of 1:1, a reaction time of 4 days, and a final total PAH removal rate of 69.65%. Another way to explain this is that a molar ratio of 6.3:5.5:4.9:1 for PS/SPC/FS/CA in this system can achieve maximum degradation efficiency. The dual-oxidant system investigated in this study exhibits significant potential for the remediation of PAHs in soil.

ABSTRACT Clumped isotopic thermometry of carbonate minerals is a valid method for revealing the thermal history of sedimentary basins. This method has been successfully applied to basins with carbonate strata, whereas its application in basins composed of clastic strata is limited. This study focused on calcite cements in the upper Permian to Triassic terrestrial clastic strata in the Junggar Basin, northwestern China. Petrological, elemental geochemical and clumped isotopic analyses were conducted in combination with vitrinite reflectance analysis and forward thermal modelling. The studied strata contain multiple generations of calcite cement: early‐ and late‐stage calcite. Relatively high δ 13 C values (−6.2‰ to −0.8‰), high δ 18 O values (−15.9‰ to −11.3‰) and low clumped isotopic temperatures (T(∆ 47 ): 31°C–43°C) suggest that the Permian and Triassic early‐stage calcite precipitated during the penecontemporaneous stage. Considering the high MnO contents (2.22%~14.05%), extremely low δ 13 C values (−60.5‰ to −38.4‰) and high T(∆ 47 ) values (95°C–132°C), the late‐stage calcite in the Triassic rocks is explained as the product of the oxidation of hydrocarbons by high‐valence Mn/Fe oxides during mesodiagenesis. The high δ 13 C values (−10.2‰ to −10.7‰) indicate that the late‐stage calcite in the Permian rocks is the product of the decarboxylation of organic acids. Constrained by the T(∆ 47 ) values of the early‐ and late‐stage calcite and forward kinetic modelling, the maximum temperature of the upper Permian is confined to 150°C during the Late Jurassic. The thermal gradient of the study area exhibited an overall decreasing trend from 40°C·km −1 in the late Permian to 22°C·km −1 in the Cenozoic. The results are 2°C–4°C per km higher than those of previous works based on vitrinite reflectance and apatite fission track annealing. This research demonstrates that the combination of clumped isotope thermometry of multistage carbonate cements and kinetic modelling can quantitatively reveal a basin's thermal history.

Located in the southwestern part of Iran, Coastal Fars is a major gas-bearing region in Iran, where a significant portion of the gas is associated with the Paleozoic petroleum system. Hydrogen sulfide is an undesirable component of natural gas, which can form in reservoirs through biogenic or abiogenic processes. In recent years, gas fields in Coastal Fars in southwestern Iran have experienced a steady increase in hydrogen sulfide content in the produced gas. It has been proven that the formation of hydrogen sulfide in the reservoirs of this region is a product of thermochemical sulfate reduction, a reaction in which sulfate-bearing minerals interact with hydrocarbons to form hydrogen sulfide, water, and carbonate minerals. When hydrocarbon components react with sulfate ions, layers of carbonate minerals are formed. Despite numerous geological and geochemical studies on the origin of hydrogen sulfide in the studied region, little attention has been paid to the phenomenon of carbonate mineralization around sulfate minerals, which is one of the key consequences of hydrocarbon oxidation. In this study, thin sections of rock samples from the Shanul field (one of the fields in Coastal Fars) were examined to identify evidence of thermochemical sulfate reduction. Scanning electron microscopy results reveal carbonate mineralization along the edges of anhydrite and celestine, caused by abiogenic sulfate reduction, confirming the occurrence of thermochemical sulfate reduction in this region. However, the reaction rate is kinetically limited by the relatively low reservoir temperature.

Abstract In the quest for sustainable and green chemistry solutions, we present the design and evaluation of a highly efficient heterogeneous nanocatalyst, AuCu@rGO/IL/TiO 2 which demonstrates remarkable potential in the degradation of MB dye and organic transformations Synthesized nanocatalyst was characterized using advanced techniquessuch as P‐XRD, FE‐SEM, HR‐TEM, XPS, etc. to elucidate its structural and functional properties. HR‐TEM micrographs revealed that the nanocatalyst exhibit a spherical morphology, with an average size of 3–4 nm optimal for catalysis, as it maximizes surface reactivity, exploits electronic and synergistic effects. BET analysis confirmed the catalyst's high specific surface area of 49.614 m 2 /g, coupled with a total pore volume of 0.08146 cm 3 /g and a mean pore radius of 1.52 nm, which improves the catalytic activity of the nanocatalyst. TGA results demonstrated that the catalyst remains stable and effective in catalyzing organic transformations up to 170 °C. With its nano‐sized active sites, high surface area, and exceptional reusability, the AuCu@rGO/IL/TiO 2 catalyst outperforms conventional catalysts, achieving a 98 % efficiency in the photodegradation of methylene blue (MB), highlighting its environmentally friendly and highly efficient nature. This work highlights the development of a sustainable supported bimetallic nanocatalyst which offers significant advancements in both environmental remediation and organic transformations.

Abstract Delineating the specific role of supported metal atoms and nanoclusters as well as their synergistic effect is particularly challenging but crucial for thermal catalytic oxidation. A programmed atomic layer deposition method is herein devised for the precise synthesis of Pt single atoms and nanoclusters coexisting on the surface of CeO2 (Pt1‐Ptn/CeO2) with controllable ratios and proximity, permitting a careful optimization of the distribution and relative proportions of these Pt species. The 80%Pt1‐20%Ptn/CeO2 catalyst with an average separation of ≈3.7 nm between single atoms and nanoclusters exhibits unprecedented performance in hydrocarbon oxidation reaction, far superior to Pt1/CeO2 or Ptn/CeO2 catalysts and outperforming all so‐far‐known Pt nano‐catalysts, this can also be extended to Pt1‐Ptn/TiO2 and Pt1‐Ptn/ZrO2 catalysts. The intrinsic investigations reveal a synergistic dual‐active‐site catalytic mechanism, involving that the polarized Pt atoms enable the fast dissociation and migration of activated hydrocarbons toward the nanoclusters center to further react with the surrounding excited oxygen. The synthesis strategy and synergistic chemistry demonstrated in this work provide a generalizable platform for the future design of well‐defined complex multi‐competent‐site catalysts for efficient thermo‐catalytic oxidation reactions.