Search Results (305)

Ionic liquids (ILs) are salts that are liquid at or below 100 °C. They are composed entirely of ions and have unique properties like negligible vapor pressure, high thermal stability, and tunable structures. These characteristics make them a promising alternative to traditional, often volatile and toxic organic solvents in the petrochemical industry. They have broad applications in chemical and petrochemical industry processes. Ionic liquids may be applied in the following processes: desulfurization, benzene toluene xylene (BTX) separation, alkylation, and carbon capture units. Two different ionic liquid-based process configurations have been evaluated for BTX separation. It has been found that the process configuration working with 1-ethyl-3methylimidazolium tricyanomethanide ([emim][TCM]) reduces the energy costs and capital expenditures associated with the Morphylane process by 67 and 63%, respectively. It also reduces solvent costs, confirming it as a cleaner alternative. The hydrodesulfurization (HDS) process is operated under harsh conditions, such as high temperature and high pressure and the requirement of a noble catalyst and hydrogen. High-Temperature Hydrogen Attack (HTHA) failure occurs at high temperatures between the gaseous molecular hydrogen contained inside the steel pressure vessel and the carbon atoms located in the steel matrix or in carbides. Methane molecules are produced during this reaction. This phenomenon can consequently lead to a loss of mechanical properties due to surface decarburization and to the formation of defects caused by methane bubbles mainly located at grain boundaries. The application of ionic liquids (ILs) in oil refineries offers significant advantages, such as safety, environmental sustainability, and process efficiency, primarily by serving as versatile alternatives to hazardous traditional solvents and catalysts. Across BTX extraction, carbon capture, and desulfurization/HDS-adjacent service, the recurring barriers are high viscosity, difficult regeneration, solvent cost/inventory and uncertain long-term stability. Full article

To elucidate the combustion behavior and molecular-scale reaction mechanisms of Fushun oil shale kerogen under oxy-fuel atmospheres, ReaxFF molecular dynamics simulations were performed based on a previously constructed kerogen model. Five reaction systems were established: 21% O₂/79% N₂, 21% O₂/79% CO₂, 35% O₂/65% CO₂, 55% O₂/45% CO₂, and 75% O₂/25% CO₂. Under programmed heating, the evolution of chemical bonds, gaseous products, char, tar and gas transformation, and system potential energy was systematically analyzed. The results show that, at the same O₂ concentration, CO₂ delays low-temperature oxidation, shifting C–C and C–H bond cleavage and O₂ consumption to higher temperatures. At elevated temperatures, however, CO₂-related pathways promote carbon skeleton fragmentation and CO formation. Increasing O₂ concentration from 21% to 75% advances O₂ participation and H₂O formation, suppresses low-temperature CO accumulation, accelerates char consumption, and drives the system toward complete oxidation dominated by small-molecule gases. Potential energy analysis further indicates that higher O₂ concentrations advance the intense exothermic oxidation stage. A four-stage oxy-fuel combustion mechanism is proposed, providing molecular-level insight into the coupled effects of CO₂ and O₂ concentration. Full article

This paper reviews the significant steps of the atomic–molecular theory, after Avogadro’s intimation of the equal volume/equal number of particles hypothesis until the final assertion embodied in Cannizzaro’s Sunto. Berzelius’s atomism, authoritatively present among chemists in the first decades of nineteenth century, is outlined. Applying volume theory, atomic weights were determined and later revised considering heat capacity experiments on solid elements and the law of isomorphism. The peculiar traits of Berzelius’s atomism are (a) the restricted validity of Avogadro’s hypothesis to only elementary gases, and (b) the opposition to the existence of elementary polyatomic molecules. Next, Dumas’ experiments on vapors are described, aimed at supporting Avogadro’s hypothesis, whose perplexing results were ingeniously resolved by Gaudin assuming that the elementary molecules may contain unequal numbers of component atoms. In the fifth decade of the century, Gerhardt and Laurent established molecular formulae with reference to standard volumes. Finally, at the end of the sixth decade, Cannizzaro published Sunto di un Corso di Filosofia Chimica, in which he fully acknowledges Avogadro’s hypothesis, together with all its implications, and describes how to arrive at molecular and atomic weights from gaseous densities. A brief account of the Karlsruhe congress is included, emphasizing the scientific personality of Cannizzaro. Full article

Agronomic biofortification offers an environmentally friendly way to improve crop nutrition. The biofortification of vegetables with iodine has attracted increasing attention due to its significance for human health. Hydrogen sulphide (H₂S) is a gaseous signalling molecule that affects many physiological and biochemical processes in plants. Lettuce (Lactuca sativa L.) plants were cultivated under controlled greenhouse conditions. Foliar applications of potassium iodate (KIO₃) and hydrogen sulphide (H₂S, supplied by sodium hydrosulphide (NaHS)) were applied separately and together (H₂S + KIO₃). Evaluations included growth parameters, photosynthetic pigments, biochemical metabolites, antioxidant enzyme activities, plant hormone levels, and mineral nutrient contents. All treatments resulted in significant changes in plant growth and physiological traits compared to the control. The combined application resulted in greater responses across several parameters; however, these observations do not demonstrate a causal or mechanistic interaction between the treatments. The combined application increased plant fresh weight by ~42% and leaf area by ~35% compared to the control. Total chlorophyll content approximately doubled (≈100% increase), while SOD, POD, and CAT activities increased by up to ~160%, ~13%, and ~40%, respectively. Proline and sucrose contents increased by approximately 100% and 85%. Hormonal changes included increases in indole-3-acetic acid (~44%) and cytokinins (~55%), and a decrease in abscisic acid (~20%). In addition, several macro- and micronutrients in leaves and roots were affected by the treatments. The combined application of KIO₃ and H₂S was associated with greater responses across several measured parameters than either compound alone; however, these observations do not demonstrate a causal or mechanistic interaction between the two compounds. Furthermore, as the experiment was conducted under non-stress greenhouse conditions, the observed physiological responses should be interpreted as changes in metabolic and regulatory processes rather than direct evidence of enhanced stress tolerance. Overall, the results indicate that foliar application of KIO₃ and H₂S can influence growth and physiological traits of lettuce under controlled conditions. Full article

Hydrogen sulfide (H₂S) functions as a pivotal gaseous signaling molecule in plants, yet its role in promoting crop yield remains elusive. Here, we demonstrate that sodium hydrosulfide (NaHS) application, a donor of hydrogen sulfide (H₂S), significantly accelerates growth, promotes flowering, and enhances grain yield in rice (Oryza sativa L.). Optimal NaHS treatment increased plant height, root length, and biomass accumulation, concomitant with elevated sucrose, starch, chlorophyll contents, and nitrate reductase activity. Integrated transcriptomic and proteomic analyses revealed that NaHS reprograms key biological pathways, including photosynthesis, carbon metabolism, lipid metabolism, the hormone signal transduction pathway, and reactive oxygen species (ROS) homeostasis. NaHS also remodels fatty acid metabolism, significantly increasing unsaturated fatty acids, linoleic acid (C18:2n6c), and α-linolenic acid (C18:3n3)—the latter serving as the direct precursor for JA biosynthesis—thereby fueling jasmonic acid (JA) biosynthesis. NaHS treatment also induced ROS accumulation while simultaneously activating antioxidant enzymes, maintaining redox homeostasis, and promoting cell proliferation in root meristems. Transmission electron microscopy revealed that NaHS enlarges peroxisomes and increases chloroplast oil body number, linking organellar dynamics to enhanced JA synthesis and ROS signaling. Collectively, our findings establish NaHS as a novel chemical regulator that coordinates JA and ROS signaling to boost rice growth, flowering, and grain yield, offering a promising strategy to improve crop productivity. Full article

Formic acid (FA) has emerged as a promising liquid hydrogen storage material, yet efficient photothermal dehydrogenation catalysts with high activity and H₂ selectivity remain challenging. Herein, a polymetallic synergistic PdCu/M-ZNC (where M represents the co-doped In, Sn and Mo species) is fabricated by molten-salt-assisted pyrolysis of ZIF-8 precursors followed by metal incorporation. The unique molten salt environment effectively preserves the porous architecture of ZIF-8, enabling the secure anchoring of PdCu alloy nanoparticles onto the carbonaceous matrix enriched with M-N_x coordination sites. Under light irradiation, the PdCu alloy sites kinetically accelerated the overall adsorption and activation of FA molecules. Based on empirical observations and corroborated by the established literature, this alloying effect was inferred to facilitate the C-H bond cleavage and HCOO* desorption processes. Concurrently, the M-N_x sites act as efficient electron transfer channels, facilitating the rapid coupling of photogenerated electrons with protons (H⁺) to evolve H₂. Consequently, the optimal catalyst exhibits an enhancement in gaseous product yield (404.46 mmol/g/h) and H₂ selectivity (67.49%) at 75 °C. This work offers a catalyst design that aligns with several principles of green chemistry: it maximizes the atom utilization of precious Pd, incorporates synergistic non-precious metals within MOF-derived frameworks to enhance stability, and leverages solar energy to drive hydrogen production under mild conditions, presenting a more sustainable pathway for hydrogen release from liquid carriers. Full article

Nitric oxide (NO) is a gaseous biocompatible radical molecule with demonstrated biomedical and antimicrobial benefits. Developing adaptable, long-lasting delivery systems for NO has become an essential goal for both combating resistant bacterial growth and providing sustained medical benefits. Silsesquioxane (SQ)-based organogels were chosen and synthesized as robust, tunable NO-release platforms. These highly stable SQ gel frameworks, composed of silicon–oxygen backbones with variable R groups, exhibited high porosity and surface area and offered chemical versatility, enabling control over NO loading and release. 3-Mercaptopropyl groups were utilized as sulfur-based NO-releasing substituents (-RSNOs), with additional R groups capable of altering accessibility to RSNO sites through hydrophobicity and steric hindrance. The NO release profile, rate, and duration of the functionalized gels were also tailored by adjusting the number of RSNO sites in the elastomeric system, thereby enabling a customizable release profile. This combination of NO-releasing silsesquioxanes with silicone elastomers yields composite materials that are integratable into biomedical applications, offering NO release up to 40 days within modeled physiological conditions in PBS buffer. Full article

Neuropsychiatric conditions constitute a major and growing global health burden, with prevalence rates that continue to rise worldwide. Although these disorders have traditionally been studied primarily from a neuronal perspective, accumulating evidence indicates that immune dysregulation and inflammatory processes play a central role in their pathophysiology. In this review, we advance the hypothesis that nitric oxide (NO)-mediated alterations in blood–brain barrier (BBB) integrity represent a critical mechanistic link between inflammation and central nervous system dysfunction in neuropsychiatric disorders. NO is a gaseous multifunctional signaling molecule involved in vascular homeostasis and immune responses, and its dysregulated production, together with aberrant protein S-nitrosylation, has been implicated in several neuropsychiatric conditions. However, the specific mechanisms by which NO signaling contributes to BBB dysfunction remain incompletely defined. Here, we synthesize current evidence supporting a role for NO-dependent vascular and inflammatory pathways in BBB disruption and discuss how these processes may contribute to the onset and progression of neuropsychiatric conditions. Clarifying these mechanisms may provide novel insights into disease pathogenesis and identify therapeutic targets aimed at preserving BBB integrity and limiting neuroinflammation. Full article

The rational design and regulation of interfacial microenvironments represents an effective strategy for enhancing reaction performance. Previous studies have demonstrated that constructing air–liquid–solid triphase interfaces can substantially enhance catalytic reactions involving gaseous reactants. However, research on regulating the triphasic interfacial microenvironment remains limited and challenging. Herein, we fabricated a triphase photocatalytic system by depositing hydrophobic materials onto ordered TiO₂ porous (OTP), achieving significantly enhanced performance in visible-light-driven dye-sensitized photooxidation. Further, we regulated the triphasic microenvironment by systematically adjusting the chain length of hydrophobic molecules. It was found that the chain length greatly affects the interfacial properties, including O₂ concentration, the organic molecule adsorption and the interfacial electron transfer efficiency, thereby influencing photocatalytic reaction kinetics and pathways. We demonstrated a high-performance triphase photocatalytic system using 1H,1H,2H,2H-perfluorooctyl triethoxysilane as the hydrophobic material, which optimized multiple interfacial properties through synergistic effects, leading to optimal photocatalytic performance. Full article

Surface-enhanced Raman scattering (SERS) has become an effective and sensitive analysis tool for the detection of various molecules. Nevertheless, it is a challenge to fabricate reusable SERS substrates for detecting gaseous molecules. Here, a self-calibrated and reusable SERS substrate has been developed for the quantitative analysis of n-butylamine. The obtained substrate enhances gas enrichment capability through the coordination interaction of Fe₂O₃ with the porous structure of ZIF-8, and strengthens the Raman signal intensity by the localized surface plasmon resonance of Ag nanoparticles. Ethanethiol is employed as an internal standard to enhance analysis accuracy. The substrate exhibits excellent quantitative analysis (linear correlation coefficient, R² = 0.996), signal uniformity (RSD = 6.3%), and batch reproducibility (RSD = 4.8%). Moreover, the substrate achieves self-cleaning through photocatalysis. After five cycles, the substrate retains high SERS activity (RSD = 3.13%), exhibiting excellent reusability. Full article

This study investigates the feasibility of treating acidic gases produced in oilfields using a novel method that combines cavitation-jet reactor (CJR) technology with electric arc discharge (EAD). The integration of these two approaches enhances the ionization process by converting neutral gas molecules into chemically reactive ion-radical and radical fragments. These highly reactive species eventually recombine, creating new chemical compounds and simpler molecules from incoming acid gas and water vapor. Theoretical validation and experimental demonstration have revealed possible mechanisms and pathways of low-temperature plasma-chemical processes resulting from the synergistic effects of cavitating-jet flow and arc discharge on the molecular degradation of neutral gaseous molecules, such as hydrogen sulfide and carbon dioxide in water vapor, which lead to the generation of new compounds. Research indicates that the most effective method for processing associated petroleum gas (APG) involves minimizing the sequential nature of chemical reactions in low-temperature non-equilibrium plasma environments, thus eliminating the need for costly and complex catalysts. Additionally, studies have shown that the cavitation-jet flow of a gas–vapor–liquid mixture, when combined with an electric arc discharge in the truncated region of the low-temperature plasma of CJR, results in the synthesis of hydrogen, two forms of S₈ (S₈^I and S₈^II), crystalline carbon, and its organic derivatives containing oxygen and nitrogen, specifically methanol, ethanol, acetone, and acetonitrile. The data obtained suggest that the generation of low-temperature plasma in the cavitation-jet chamber, induced by an electric discharge, is essential for the production of reaction products, such as hydrogen, sulfur, and oxygen- and nitrogen-containing derivatives of organic carbon, when water vapor and acid gas molecules traverse the reactor. Full article

Thiocyanate (SCN⁻), a persistent inorganic contaminant widely present in industrial wastewater, poses severe risks to plant growth and photosynthesis. Hydrogen sulfide (H₂S) is an emerging gaseous signaling molecule involved in the regulation of plant stress responses; however, its role in modulating Rubisco energy metabolism and activation under SCN⁻ stress remains unclear. Here, we investigated the effects of exogenous H₂S on magnesium homeostasis, ATP/NADPH metabolism, Rubisco activation, and photosynthetic performance in rice seedlings exposed to SCN⁻ stress via physiological, biochemical, and transcriptional approaches. We found that exogenous H₂S significantly increased Mg²⁺ accumulation, enhanced H⁺-ATPase and Mg²⁺-ATPase activities, and promoted Rubisco activase (RCA) abundance and activity. These changes were accompanied by reduced steady-state ATP and NADPH contents, indicating that increased energy consumption was driven by accelerated Calvin cycle turnover. At the transcriptional level, H₂S regulated key genes involved in ATP hydrolysis, Mg²⁺ transport, Rubisco activation, and chlorophyll biosynthesis. Consequently, the chlorophyll content, stomatal conductance, and transpiration rate improved under SCN⁻ stress. Collectively, our results demonstrate that exogenous H₂S enhances photosynthetic efficiency and Rubisco carboxylation capacity by coordinating Rubisco energy metabolism and activation. Full article

High-resolution NMR spectroscopy is the leading method for determining nuclear magnetic moments. It is designed to measure stable nuclei, which can be investigated in macroscopic samples. In this work, we discuss the progress in research into light nuclei from the first three periods of the Periodic Table and several selected heavy nuclides. The ¹H and ³He nuclear magnetic moments, established using the new double Penning trap facility, are also considered. Both nuclei can be used as references in gaseous mixtures. Gas-phase NMR spectroscopy enables precise measurements of the frequencies and shielding constants of isolated single molecules. They can be used to determine new, accurate nuclear magnetic moments of nuclides in stable, gaseous substances. Particular attention is paid to the importance of diamagnetic corrections for obtaining accurate results. Finding precise diamagnetic corrections—shielding factors —even for light nuclei in molecules is a significant challenge. To date, nuclear moments have been obtained primarily from experimental data. The theoretical approach is mostly unable to predict these values accurately. Some remarks are also made on pure theoretical treatments of nuclear moments. Full article

Fire-retardant intumescent coatings offer an effective means of enhancing the fire resistance of combustible substrates such as wood. These coatings have a complex chemical composition and, when exposed to temperatures above 200 °C, undergo an intumescent reaction accompanied by the release of non-flammable gases, forming an expanded, charred layer with low thermal conductivity. This provides thermal insulation and acts as a physical barrier against heat, oxygen, and flammable volatiles. In this study, the applicability of several thermoanalytical techniques for evaluating the performance of three different intumescent coatings applied to spruce wood was investigated. Simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed that coating No. 3 was the most efficient, initiating substrate protection at the lowest temperature and reducing the combustion enthalpy by approximately 50% compared to uncoated wood. DSC-microscopy visualization enabled direct observation of the intumescent expansion, degradation of the carbonized protective layer, and delayed thermal decomposition of coated wood. Furthermore, a comparison between TGA-MS and TGA-IST16-GC-MS demonstrated the superiority of chromatographic separation for identifying evolved gaseous products. While TGA-MS is effective for detecting small gaseous species (e.g., H₂O, CO₂, formaldehyde), TGA-IST16-GC-MS enables the deconvolution of many degradation products evolving simultaneously, allowing for distinction between flame-retardant-related species, polymer backbone fragments, nitrogen-rich heterocycles, and small oxygenated molecules in the most effective coating. Full article

Nitric oxide (NO), a fundamental gaseous signaling molecule, is indispensable for cardiovascular homeostasis. This review synthesizes the expansive field of NO biology within the unifying framework of Nitric Oxide Equilibrium (NOE), i.e., the critical balance between its synthesis, bioavailability, and degradation. In a physiological state, NOE maintains vascular health by regulating blood pressure, preventing thrombosis, suppressing inflammation, and optimizing both cardiac and mitochondrial function. Here, we analyze how NOE disruption, primarily through oxidative stress and enzymatic dysfunction, underlies the pathogenesis of major cardiovascular diseases, including atherosclerosis, heart failure, ischemia–reperfusion injury, and cerebrovascular diseases like stroke. A critical evaluation of therapeutic strategies designed to restore NOE is presented, encompassing classic NO donors and phosphodiesterase-5 inhibitors, alongside next-generation soluble guanylate cyclase modulators and precision nanomedicine approaches. By identifying key knowledge gaps and methodological hurdles, this review charts a course for future research focused on biomarker-guided interventions and personalized medicine. Ultimately, we frame the restoration of NOE as a paramount therapeutic goal, crucial to translating decades of molecular research into effective clinical practice. Full article