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The random-phase approximation (RPA) includes a subset of higher than second-order correlation-energy contributions, but stays in the same complexity class as the second-order Møller–Plesset perturbation theory (MP2) in both Gaussian-orbital and plane-wave codes. This makes RPA a promising ab initio electronic structure approach for the binding energies of molecular crystals. Still, some issues stand out in practical applications of RPA. Notably, compact clusters of nonpolar molecules are poorly described, and the interaction energies strongly depend on the reference single-determinant state. Using the many-body expansion of the binding energy of a crystal, we investigate those issues and the effect of beyond-RPA corrections. We find the beneficial effect of quartic-scaling exchange and non-ring coupled-cluster doubles corrections. The nonadditive interactions in compact trimers of molecules are improved by using the self-consistent Hartree–Fock orbitals instead of the usual Kohn–Sham states, but this kind of orbital input also leads to underestimated dimer energies. Overall, a substantial improvement over the RPA with a renormalized singles approach is possible at a modest quartic-scaling cost, which encourages further research into additional RPA corrections. [ABSTRACT FROM AUTHOR]

Thermodynamic potentials play a substantial role in numerous scientific disciplines and serve as basic constructs for describing the behavior of matter. Despite their significance, comprehensive investigations of their topological characteristics and their connections to molecular interactions have eluded exploration due to experimental inaccessibility issues. This study addresses this gap by analyzing the topology of the Helmholtz energy, Gibbs energy, Grand potential, and Null potential that are associated with different isothermal boundary conditions. By employing Monte Carlo simulations in the NVT, NpT, and μVT ensembles and a molecular-based equation of state, methane, ethane, nitrogen, and methanol are investigated over a broad range of thermodynamic conditions. The predictions from the two independent methods are overall in very good agreement. Although distinct quantitative differences among the fluids are observed, the overall topology of the individual thermodynamic potentials remains unaffected by the molecular architecture, which is in line with the corresponding states principle—as expected. Furthermore, a comparative analysis reveals significant differences between the total potentials and their residual contributions. [ABSTRACT FROM AUTHOR]

Potential applications of previously synthesized pillared graphene oxide frameworks with phenyldiboronic acid linkers in the field of the adsorption and separation of polar protic and aprotic liquid solvents have been systematically explored using grand canonical Monte Carlo simulations. Particular attention was initially paid to the adsorption of pure liquid water, methanol, and dimethyl sulfoxide. The results obtained a significant increase in the isosteric heat of adsorption at low uptake in the case of dimethyl sulfoxide, which is about 17.9 and 26.8 kJ/mol higher than the values corresponding to methanol and water adsorption. These findings indicated that from a thermodynamic point of view, these pillared graphene oxide frameworks could be used in the separation of dimethyl sulfoxide–water liquid mixtures. Systematic grand canonical Monte Carlo simulations were then subsequently performed for dimethyl sulfoxide–water mixtures, with a low dimethyl sulfoxide concentration. The calculated values of the separation selectivity indicate that these materials could have potential applications in the separation of these mixed liquid solvents. Molecular dynamics simulations performed for a representative adsorbed mixture have revealed a substantial slowing down of the dynamics under confinement, particularly in the case of the hydrogen bonds formed between water and dimethyl sulfoxide. [ABSTRACT FROM AUTHOR]

The focus of our study is an in-depth investigation of the quantum effects associated with the surface tension and other thermodynamic properties of nanoscopic liquid drops. The behavior of drops of quantum Lennard-Jones fluids is investigated with path-integral Monte Carlo simulations, and the test-area method is used to determine the surface tension of the spherical vapor–liquid interface. As the thermal de Broglie wavelength, λB, becomes more significant, the average density of the liquid drop decreases, with the drop becoming mechanically unstable at large wavelengths. As a consequence, the surface tension is found to decrease monotonically with λB, vanishing altogether for dominant quantum interactions. Quantum effects can be significant, leading to values that are notably lower than the classical thermodynamic limit, particularly for smaller drops. For planar interfaces (with infinite periodicity in the direction parallel to the interface), quantum effects are much less significant with the same values of λB but are, nevertheless, consequential for values representative of hydrogen or helium-4 at low temperatures corresponding to vapor–liquid coexistence. Large quantum effects are found for small drops of molecules with quantum interactions corresponding to water, ethane, methanol, and carbon dioxide, even at ambient conditions. The notable decrease in the density and tension has important consequences in reducing the Gibbs free-energy barrier of a nucleating cluster, enhancing the nucleation kinetics of liquid drops and of bubble formation. This implies that drops would form at a much greater rate than is predicted by classical nucleation theory. [ABSTRACT FROM AUTHOR]

Treatment of two classes of oxazolinyl‐indolate ligand precursors with an equivalent trimethylaluminum reagent afforded four corresponding aluminum dimethyl complexes. Intramolecular functional groups were employed to switch coordination behaviors, resulting in the formation of two classes of five‐ or six‐membered aluminum metallocyclic complexes. The screening of the prepared aluminum complexes, mediated by 9‐anthracenemethanol as the initiating reagent in the ring‐opening polymerization of ε‐caprolactone, showed significant activities at room temperature. The aluminum compound ligated by 2‐(1H‐indol‐2‐yl)‐4,4‐dimethyl‐4,5‐dihydrooxazole possessed a suitable chelated ring size, and its intrinsic electronic properties maintained higher activity. [ABSTRACT FROM AUTHOR]

Acetic acid (AA), a vital compound in chemical production and materials manufacturing, is conventionally synthesized by starting with coal or methane through multiple steps including high‐temperature transformations. Here we present a new synthesis of AA from ethane through photocatalytic selective oxidation of ethane by H2O2 at 0–25 °C. The catalyst designed for this process comprises g‐C3N4 with anchored Pd1 single‐atom sites. In situ studies and computational simulation suggest the immobilized Pd1 atom becomes positively charged under photocatalytic condition. Under photoirradiation, the holes on the Pd1 single‐atom of OH−Pd1⊕ ${{}^{\oplus }}$ /g‐C3N4 serves as a catalytic site for activating a C−H instead of C−C of C2H6 with a low activation barrier of 0.14 eV, through a concerted mechanism. Remarkably, the selectivity for synthesizing AA reaches 98.7 %, achieved under atmospheric pressure of ethane at 0 °C. By integrating photocatalysis with thermal catalysis, we introduce a highly selective, environmentally friendly, energy‐efficient synthetic route for AA, starting from ethane, presenting a promising alternative for AA synthesis. This integration of photocatalysis in low‐temperature oxidation demonstrates a new route of selective oxidation of light alkanes. [ABSTRACT FROM AUTHOR]

Unlocking the afterglow properties of the fluorescence molecules at room temperature is an urgent challenge. Herein, inks prepared with dimethyl terephthalate (DTT) and carbazole (Cz) analogs with heteroatom (C, S, and O) substituents on the N as host and guest molecules can be directly sprayed onto different substrates to unlock the excitation‐wavelength dependent (Ex‐De) afterglow characteristics of the guest compound. Additionally, with the increase in the number of lone pair electrons, spin‐orbit coupling (SOC) increases, resulting in a longer afterglow duration lasting up to 4.5 s with Φp>27%. Theory calculations and experiments indicate that the afterglow originated from the interactions between the host and guest molecules restricting the non‐radiative transition of the triplet excitons. Different Ex (with watershed at 310 nm) lead to the variation in the conformation of the S0DTT and S1DTT, which in turn affects the strength of host‐guest interactions and contributes to the Ex‐De characteristics. Benefiting from facile preparation, substrate‐independent applicability, and Ex‐De characteristics, the afterglow samples are demonstrated for applications in multilevel information security fields. This work proposes a general strategy for unlocking the afterglow emission of traditional molecules, which is valuable for the discovery of high‐performance afterglow materials in the future. [ABSTRACT FROM AUTHOR]

Grape pomace is a major winery solid residue and several tons are annually produced worldwide. Since it is a valuable source of high value-added compounds, many strategies have been implemented for its valorization. The extraction of bioactive molecules with a broad range of applications is certainly the most investigated topics. In this context, oleanolic acid, a triterpenoid with a relevant biological activity, has been recently detected in grape pomace in remarkable quantities (0.45 mg per gram of fresh pomace). Herein, we report on a selective extraction of oleanolic acid from grape pomace by using dimethyl carbonate (DMC), a recommended green solvent as a better alternative to fossil-based solvents. Chemical–physical properties, Hildebrand's solubility and Kamlet–Abboud–Taft parameters have been considered to select a greener alternative to fossil-based solvents and theoretical calculations have been performed to determine the interaction between DMC and the oleanolic acid. The obtained grape pomace extracts were characterized by means of NMR and LC-MS. DMC allows the recovery of oleanolic acid from grape pomace, due to its weak polarity and poor ability to form H-bonds, with a molar selectivity of 61%, thus promoting the adoption of alternative green and sustainable technologies for biomass residue valorization. Also, DMC was recycled and reused in three consecutive extractions and no significant losses in terms of oleanolic acid extraction yield were detected. [ABSTRACT FROM AUTHOR]

An efficient route for the chemoselective deoxygenation of benzylphenyl sulfones to the corresponding sulfides has been developed using a mixture of 1,2-bis(diphenylphosphino)ethane(dppe) and NBS as an effective promoter. This is the first development on the deoxygenation of diverse benzylphenyl sulfones under metal-free conditions. The mild reaction conditions, formation of the water soluble by-product and tolerance of a wide range of functional groups promote its broad applications in organic synthesis. [ABSTRACT FROM AUTHOR]

Phosphotungstic acid with a Keggin structure as an efficient, simple and green catalyst for the phosphinylation of secondary propargyl alcohols with phosphine oxides to afford γ-ketophosphine oxides with up to 88% isolated yield was developed using dimethyl carbonate as a green solvent. Diaryl- or alkylaryl-substituted propargyl alcohols, and diaryl or arylalkylphosphine oxides could tolerate the system, which reduced the catalyst dosage, and avoided the use of multi-components and toxic solvents. More interestingly, phosphotungstic acid exhibited the best activity when 0.58 moles of water were added per mole of HPWA, elevating the yield from 55% to 85%. An 18O labelled product was afforded using trace H218O instead of H2O, indicating the participation of water in the reaction. Besides, our work underscores the importance and effect of a small amount of water, acting to promote the transformation of secondary propargyl alcohols into enones, which should be the real intermediates of the reaction. A mechanism involving a carbocation, Meyer–Schuster rearrangement and Michael addition of enones was proposed. [ABSTRACT FROM AUTHOR]

We report on the insertion of electron deficient alkyne, dimethyl acetylene dicarboxylate (DMAD), into the E–Si bond of hypersilyl tetrylenes, PhC(NtBu)2ESi(SiMe3)3 (E = Ge and Sn), at room temperature. Uniquely, the germylene leads to cis alkenes, while the stannylene gives access to trans alkenes, and the insight into divergent stereoselectivity has been obtained by DFT studies. [ABSTRACT FROM AUTHOR]

Ethane is the most abundant non-methane hydrocarbon in the troposphere, where it impacts ozone and reactive nitrogen and is a key tracer used for partitioning emitted methane between anthropogenic and natural sources. However, quantification has been challenged by sparse observations. Here, we present a satellite-based measurement of tropospheric ethane and demonstrate its utility for fossil-fuel source quantification. An ethane spectral signal is detectable from space in Cross-track Infrared Sounder (CrIS) radiances, revealing ethane signatures associated with fires and fossil fuel production. We use machine-learning to convert these signals to ethane abundances and validate the results against surface observations (R2 = 0.66, mean CrIS/surface ratio: 0.65). The CrIS data show that the Permian Basin in Texas and New Mexico exhibits the largest persistent ethane enhancements on the planet, with regional emissions underestimated by seven-fold. Correcting this underestimate reveals Permian ethane emissions that represent at least 4-7% of the global fossil-fuel ethane source. The authors have developed a satellite-based method that detects tropospheric ethane, revealing major sources like fires and fossil fuels. It agrees with ground-based observations and shows Permian Basin emissions of ethane are higher than estimated. [ABSTRACT FROM AUTHOR]

Direct synthesis of dimethyl carbonate (DMC) from CO2 and CH3OH holds significant economic and environmental value. Numerous catalysts have been employed for this reaction, yet further enhancement of its activity requires a deeper understanding of the catalyst's structure–activity relationship and catalytic mechanism. In this study, we utilized structurally well-defined and highly tunable MOF-808 as a research platform. Functionalizing MOF-808 with ethylenediamine (MOF-808-ED) boosted the space time yield of DMC from 3.25 mmol g−1 h−1 to 7.23 mmol g−1 h−1. The experimental results demonstrate that the reaction involves acid–base synergistic catalysis, where an appropriate balance of acid–base site content is crucial for CO2 and CH3OH to produce DMC, as it facilitates the formation of the key intermediates (CH3OCOO*). Additionally, the nucleophilicity of N is stronger than that of O, further promoting the catalyst's enrichment and activation of CO2. Finally, employing in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) testing, we elucidated the mechanism by which the MOF-808-ED catalyst, with –NH2 as base sites and Zr as acid sites, facilitates the synergistic catalysis of the reaction. This study provides insights into the synergistic effects of acid–base sites on the synthesis of DMC from CO2 and methanol, offering valuable guidance for the development of high-performance catalysts. [ABSTRACT FROM AUTHOR]

Various excellent catalysts have been explored for the methanolysis of polycarbonate (PC), but it is still challenging to develop green and economical catalysts for solvent-free PC methanolysis to recover both bisphenol A (BPA) and dimethyl carbonate (DMC). Herein, green, efficient and solvent-free degradation of PC to BPA and DMC was achieved using urea as a cheap green catalyst. At 140 °C for 3 h, PC was completely degraded to BPA and DMC with yields of 93.4% and 74.7%, respectively. A possible catalytic degradation mechanism of PC was proposed by kinetic experiments and NMR, where urea, methanol and carbonate formed a six-membered ring in the reaction. It was found that the increase of urea concentration significantly reduced the activation energy, which was attributed to the fact that the increase of urea concentration made the six-membered ring easier to form and activated the carbonate bond. The degradation system can be reused directly up to 10 times and 100% degradation rate can be maintained. This work provides a simple, green and economical method for industrial PC recycling. [ABSTRACT FROM AUTHOR]

New, high‐yield derivatives of oxepino[3,2‐c]chromene were synthesized through a multicomponent reaction. This reaction involved 2‐hydroxyacetophenone, dimethyl carbonate, activated acetylenic compounds, and alkyl bromide. The reaction took place at room temperature in an aqueous environment, resulting in the formation of these innovative compounds. Oxathiepines were synthesized using multicomponent reactions of 2‐hydroxyacetophenone, dimethyl carbonate, isothiocyanate, and alkyl bromide in water at room temperature. This technology offers several benefits, including quick response times, high product yields, and easy product separation using straightforward techniques. [ABSTRACT FROM AUTHOR]

This study focused on the investigation of synthesizing new derivatives of cyclopentapyridines with high yields employing multicomponent reaction that involved vinilydene Meldrum's acid, ethyl 2‐amino‐4‐dioxo‐4‐arylbutanoates, hydrazonoyl chlorides, and activated acetylenic compounds. The reaction was conducted in water at room temperature, resulting in the synthesis of new compounds. Also, the reaction of synthesized cyclopentapyridines with dimethyl acetylenedicarboxylate was performed in water at room temperature which produced other cyclopentapyridine derivatives by elimination of N2. The advantages of this technology encompass rapid response times, high product yields, and facile product separation via uncomplicated procedures. [ABSTRACT FROM AUTHOR]

The detailed analysis of the mechanism of metathesis of N-methylformamide with dimethyl carbonate leading to the formation of N, O-dimethylcarbamate was carried out using the B3LYP/6-311++G(df,p), B3LYP-D3(BJ)/6-311++G(df,p) and ωB97XD/6-311++G(df,p) density functional methods. The reactions proceed in three stages. The first step consists in the tautomeric conversion of N-methylformamide to iminol. The second stage, which is the rate-limiting step, involves the addition of dimethyl carbonate via the N=C π-bond of iminol. The third stage of the reaction is the cleavage of the methyl formate molecule from N-methyl-N-[(hydroxy)(methoxy)methyl]-O-methylcarbamate. This conversion results in the formation of N, O-dimethylcarbamate. All stages of the reactions are catalyzed by associates of alcohols, which lead to a strong decrease in activation enthalpies. [ABSTRACT FROM AUTHOR]

A more efficient and environmentally friendly approach has been developed for synthesizing phosphonates through the Michaelis-Arbuzov reaction, catalyzed by nano-ZnO in a solvent-free environment, utilizing microwave irradiation. Before synthesis, each compound underwent in silico ADMET analysis and molecular docking to assess drug-like characteristics and their potential to inhibit α-amylase. The structure of the newly synthesized compounds was validated using spectroscopic analysis, and their in vitro inhibitory effects on α-amylase were assessed. Among the compounds, dimethyl 2-(anthracen-10-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6j), dimethyl 2-(naphthalen-1-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6h), and dimethyl 2-(1-methyl-1H-indol-3-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6e) displayed the highest inhibitory activity compared to the reference substance, acarbose. Additionally, compounds dimethyl 2-(benzo[d][1,3]dioxol-4-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6i), dimethyl 4-oxo-2-phenyl-4H-chromen-6-yl-6-phosphonate (6a), and dimethyl 2-(1H-indol-5-yl)-4-oxo-4H-chromen-6-yl-6-phosphonate (6g) exhibited nearly equivalent effective inhibitory activity when compared to the standard. The remaining compounds demonstrated moderate to good enzyme inhibition. [ABSTRACT FROM AUTHOR]

Itaconate is one of the most studied immunometabolites produced by myeloid cells during inflammatory response. It mediates a wide range of anti-inflammatory and immunoregulatory effects and plays a role in a number of pathological states, including autoimmunity and cancer. Itaconate and its derivatives are considered potential therapeutic agents for the treatment of inflammatory diseases. While immunoregulatory effects of itaconate have been extensively studied in vitro and using knockout mouse models, less is known about how therapeutic administration of this metabolite regulates inflammatory response in vivo. Here, we investigate the immunoregulatory properties of exogenous administration of itaconate and its derivative dimethyl itaconate in a mouse model of lipopolysaccharide-induced inflammation. The data show that administration of itaconate or dimethyl itaconate controls systemic production of multiple cytokines, including increased IL-10 production. However, only dimethyl itaconate was able to suppress systemic production of IFNγ and IL-1β. In contrast to in vitro data, administration of itaconate or dimethyl itaconate in vivo resulted in systemic upregulation of IL-6 in the blood. Electrophilic stress due to itaconate or dimethyl itaconate was not responsible for IL-6 upregulation. However, inhibition of succinate dehydrogenase with dimethyl malonate also resulted in elevated systemic levels of IL-6 and IL-10. Taken together, our study reports a novel effect of exogenous itaconate and its derivative dimethyl itaconate on the production of IL-6 in vivo, with important implications for the development of itaconate-based anti-inflammatory therapies. [ABSTRACT FROM AUTHOR]

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The shale gas revolution bolsters ethane supply, thereby enhancing the economic viability of ethylene production from ethane. Presently, catalytic ethane dehydrogenation technology exhibits immense potential in the realm of ethylene production. This study achieves the electrochemical oxidative dehydrogenation conversion of ethane to ethylene via a solid oxide electrolysis cell (SOEC), effectively circumventing the issue of excessive oxidation during the ethane oxidative dehydrogenation process. An active electrode with an in situ grown metal-oxide interface significantly promotes the activation of the ethane C–H bond, leading to efficient ethylene production. Under the co-electrolysis mode of ethane with CO 2 , the Co@CeO 2 electrode demonstrates exceptional performance, achieving an ethane conversion rate of 33.1% and an ethylene selectivity of 88.9% at an applied voltage of 1.0 V. Moreover, the metal-oxide interface constructed via an in situ exsolved method effectively prevents the agglomeration of nanoparticles at high temperatures, thus enhancing the catalyst's resistance to coking and stability. Notably, the electrode's performance does not exhibit significant degradation even after 100 h of electrochemical reaction. • The electrochemical oxidative dehydrogenation of ethane effectively inhibited excessive oxidation. • The in situ grown metal-oxide interface has stability and promotes the activation of the ethane C–H bond. [ABSTRACT FROM AUTHOR]

Aiming at the resource utilization of CO 2 and the value-added catalytic conversion of ethane, different reducibility oxide carriers were used to study. Through catalytic reaction experiments, catalyst characterization and kinetic analysis, the interaction between reducible carriers and active metals and their regulation on the catalytic reaction performance of ethane with CO 2 were revealed. Fe 1.5 Ni 0.5 /CeO 2 has the highest ethylene selectivity of 87% near 650 °C, and is a good catalyst for the CO 2 -assisted ethane oxidative dehydrogenation to ethylene reaction. The strong interaction between the reducible CeO 2 and ZrO 2 carriers and active metals makes the Fe–O–Ce and Fe–O–Zr covalent bonds on the Fe 1.5 Ni 0.5 /CeO 2 and Fe 1.5 Ni 0.5 /ZrO 2 catalysts stronger than Fe–O–Ti and Fe–O–Al covalent bonds on Fe 1.5 Ni 0.5 /TiO 2 and Fe 1.5 Ni 0.5 /γ-Al 2 O 3 catalysts. The lattice oxygen on the reducible catalyst is more readily involved in the reaction. The strong interaction between the active metal and the carrier results in the reduction of the FeO x species and the formation of new active sites, resulting in a high reactivity of the catalyst. The mutually promoted redox cycle between the active species Fe3+/2+-Ni2+/0 and the reducible carrier variable metal Ce4+/3+ species improves the catalytic performance for the reaction of ethane awith CO 2. • Resource utilization of CO 2 and value-added conversion of C 2 H 6 are achieved. • Reducible Fe 1.5 Ni 0.5 /CeO 2 catalyst has the highest ethylene selectivity of 87%. • Lattice oxygen on reducible carrier is more readily involved in the reaction. • Redox cycle between Fe3+/2+-Ni2+/0 and Ce4+/3+ improves catalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Conyza Canadensis SHMT1 (CcSHMT1) structure was firstly resolved and a typical α-class PLP-dependent enzyme. • The dimethyl 2-acetamido terephthalate containing compounds had excellent herbicidal activity through virtual screening and biological assays. • The compound 9ay (IC 50 =193.8 g a.i./ha) exhibited the highest herbicidal efficiency and had no obvious side-effect on maize. • The first-in-class Cc SHMT1 inhibitor that could be developed as a potent herbicide with a new mode-of-action. Herbicide application is a highly efficiency method of weed control that boots agricultural output and assures food security. The development of novel herbicides focuses on improved bioactivity and new modes of action. The amino acid biosynthesis was validated as a promising novel mode of action for herbicidal compounds. However, the amino acid biosynthesis enzyme remains largely unexplored for herbicidal targets. Serine hydroxymethyl transferase (SHMT) is an essential enzyme in the photorespiratory cycle. The study aims to explore Conyza canadensis SHMT1 (Cc SHMT1) as a promising target for herbicide discovery. Structure determination of Cc SHMT1 was resolved by X-ray crystallography. Virtual screening docking experiments were performed with Glide version 5.5. Novel derivatives of dimethyl 2-acetamido terephthalate were further designed, synthesized, and bioassay. The druggability of the inhibitor was evidenced by ultrastructural changes in mitochondria, in vivo and vitro enzyme activity assays, and genetics analysis. Cc SHMT1 has a typical PLP-dependent enzyme 3D structure. The dimethyl 2-acetamido terephthalate-containing compounds had herbicidal activity. Dimethyl 2-(2-(4-(2-(4-bromo-2-chlorophenoxy) acetyl)piperazin-1-yl)acetamido) terephthalate (Compound 9ay , EC 50 = 193.8 g a.i./ ha) exhibited the highest herbicidal activity on tested weed among the synthesized compounds. Compound 9ay had no obvious adverse effect on the growth of maize and honeybees. Compound 9ay was verified to target Cc SHMT1 as an herbicide candidate. A first-in-class Cc SHMT1 inhibitor that could be developed as a potent herbicide with a new mode of action and provide an avenue for discovering novel inhibitors of pyridoxal-5-phosphate-dependent enzymes. [ABSTRACT FROM AUTHOR]

There is a demand from the scientific, beekeeping and consumer sectors to characterize honey based on its botanical origin, as it provides unique and distinctive properties. Nevertheless, existing studies on the physicochemical properties and the sensorial profile of honey in relation to botanical origin remain insufficient. This study aimed to understand the relationships between sensory profile and various chemical compounds (minerals, sugars, water content and volatiles) of three monofloral honeys (Atractylis serratuloides, Retama sphaerocarpa and Eruca sativa) produced in Algeria using principal component analysis. Crystallization was detected as a distinctive attribute of Eruca and Atractylis honey. A candy aroma and odor with floral nuances, light color, crystallized state and the volatile compounds Alpha-Bisabolol and Beta-eudesmol characterized the Atractylis honey. Eruca honeys were distinguished by an animal and degraded odor, bitter taste, light color and the presence of Dimethyl trisulfide and Dimethyl tetrasulfide. Finally, a vegetal aroma, some saltiness and sourness, dark amber color, lower sugar content, higher K content and Lilac aldehyde and Lilac aldehyde D characterized Retama honeys. [ABSTRACT FROM AUTHOR]

Background: Maize stalk rot (MSR) caused by Fusarium graminearum is the primary factor contributing to the reduction in maize yield and quality. However, this soil‐borne disease presents a significant challenge for sustainable control through field management and chemical agents. The screening of novel biocontrol agents can aid in developing innovative and successful strategies for MSR control. Results: A total of 407 strains of bacteria were isolated from the rhizosphere soil of a resistant maize inbred line. One strain exhibited significant antagonistic activity in plate and pot experiments, and was identified as Burkholderia ambifaria H8. The strain could significantly inhibit the mycelial growth and spore germination of F. graminearum, induce resistance to stalk rot, and promote plant growth. The volatile compounds produced by strain H8 and its secondary metabolites in the sterile fermentation broth exhibited antagonistic activity. The primary volatile compound produced by strain H8 was identified as dimethyl disulfide (DMDS) using gas chromatography tandem mass spectrometry. Through in vitro antagonistic activity assays and microscopic observation, it was confirmed that DMDS was capable of inhibiting mycelial growth and disrupting the mycelial structure of F. graminearum, suggesting it may be the major active compound for strain H8. The transcriptome data of F. graminearum further indicated that strain H8 and its volatile compounds could alter pathogenic fungi metabolism, influence the related metabolic pathways, and potentially induce cell apoptosis within F. graminearum. Conclusion: Our results showed that B. ambifaria H8 was capable of producing the volatile substance dimethyl disulfide, which influenced the synthesis and permeability of cell membranes in pathogens. Thus, B. ambifaria H8 was found to be a promising biological control agent against MSR. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Two new heteroleptic cobalt(III)dialkyldithiophosphate complex cations with a 1,2-bis(diphenylphosphino)ethane (dppe) ancillary ligand having formula [Co{S2P(OR)2}2(dppe)](B(C6H5)4) (R = –C2H5 (Co–Et); –CH(CH3)2 (Co–Pr)) have been synthesized and characterized spectroscopically as well as via single crystal X-ray diffraction analysis. The single crystal X-ray diffraction analyses reveal that the immediate geometries around Co(III) in both complexes are distorted octahedral, which are satisfied by four sulfur atoms of two dialkyldithiophosphate ligands and two phosphorus centers of the dppe ligand. These complex cations are neutralized by tetraphenyl borate B(C6H5)4 anions. The solid-state framework of both complexes are stabilized by C–H⋯π and C–H⋯C interactions. The nature of these interactions have been addressed with the help of Hirshfeld surface analysis, and percent contributions of pertinent interactions in the crystal structure of these complexes have been addressed using fingerprint plots. Both complexes have been used as heterogeneous electrocatalysts for the oxygen evolution reaction (OER). Results suggest that Co–Et is a better electrocatalyst for the OER, displaying an onset potential of 1.68 V and Tafel slope of 114 mV dec−1. Furthermore, in the homogeneous electrocatalysis of the hydrogen evolution reaction (HER) using trifluoroacetic acid, the overpotential for Co–Et and Co–Pr have been 1.05 V and 0.92 V, respectively, with turnover frequencies of 1518 s−1 and 287.5 s−1, respectively. Overall, heterogeneous OER and homogenous HER results suggest that Co–Et can be used as an efficient molecular electrocatalyst for oxygen/hydrogen evolution reactions. [ABSTRACT FROM AUTHOR]

The urgency to mitigate environmental impacts from anthropogenic CO2 emissions has propelled extensive research efforts on CO2 reduction. The current work reports a novel approach involving transforming CO2 and ethane into carbon nanotubes (CNTs) using earth‐abundant metals (Fe, Co, Ni) at 750 °C. This route facilitates long‐term carbon storage via generating high‐value CNTs and produces valuable syngas with adjustable H2/CO ratios as byproducts. Without CO2, direct pyrolysis of ethane undergoes rapid deactivation. The participation of CO2 not only enhances the durability of the catalyst, but also contributes about 30 % of the CNTs production, presenting a viable solution to CO2 challenges. The CNT morphology depends on the catalyst used. Co‐ and Ni‐based catalysts produce CNT with a 20 nm diameter and micrometer length, whereas Fe‐based catalysts yield bamboo‐like structures. This work represents a pioneering effort in utilizing CO2 and ethane for CNT production with potential environmental and economic benefits. [ABSTRACT FROM AUTHOR]

Polysulfides are endogenously produced in mammals and generally associated with protective functions. Our aim was to investigate the effect of dimethyl trisulfide (DMTS) in a mouse model of acute stress. DMTS activates transient receptor potential ankyrin 1 (TRPA1) channels and leads to neuropeptide release, potentially that of substance P (SP). We hypothesize that DMTS might inhibit the degrading enzymes of endocannabinoids, so this system was also investigated as another possible pathway for mediating the effects of DMTS. Trpa1 gene wild-type (WT) and knockout (KO) mice were used to confirm the role of the TRPA1 ion channel in mediating the effects of DMTS. C57BL/6J, NK1 gene KO, and Tac1 gene KO mice were used to evaluate the effect of DMTS on the release and expression of SP. Some C57BL/6J animals were treated with AM251, an inhibitor of the cannabinoid CB1 receptor, to elucidate the role of the endocannabinoid system in these processes. Open field test (OFT) and forced swim test (FST) were performed in each mouse strain. A tail suspension test (TST) was performed in Trpa1 WT and KO animals. C-FOS immunohistochemistry was carried out on Trpa1 WT and KO animals. The DMTS treatment increased the number of highly active periods and decreased immobility time in the FST in WT animals, but had no effect on the Trpa1 KO mice. The DMTS administration induced neuronal activation in the Trpa1 WT mice in the stress-related brain areas, such as the locus coeruleus, dorsal raphe nucleus, lateral septum, paraventricular nucleus of the thalamus, and paraventricular nucleus of the hypothalamus. DMTS may have a potential role in the regulation of stress-related processes, and the TRPA1 ion channel may also be involved in mediating the effects of DMTS. DMTS can be an ideal candidate for further study as a potential remedy for stress-related disorders. [ABSTRACT FROM AUTHOR]

The 1,3-dipolar cycloaddition reaction of substituted dinitroacetonitriles with isoquinoline in the presence of acetylene dicarboxylic acid dimethyl ester results in the formation of a mixture of diastereomeric dimethyl 2-dinitromethyl-1,1bH-pyrimido[2,1-a]isoquinoline-3,4-dicarboxylates. The obtained compounds can be considered as promising synthons with potential antituberculosis and fungicidal activity. [ABSTRACT FROM AUTHOR]

Chromium and molybdenum incorporated MgO and MgO–C catalysts were synthesized for hydrogen production from a non-oxidative ethane dehydration reaction. Hydrogen production studies were carried out using a microwave-heated reactor system. The study investigated the effects of reaction temperature, type of active metal, and catalyst preparation method (physical mixture or core–shell structure) on hydrogen selectivity and ethane conversion during dehydrogenation reactions. The results showed that the optimal reaction temperature for the non-oxidative ethane dehydration reaction was 450 °C. Above this temperature, the selectivity of undesired byproducts increased. Catalysts containing molybdenum exhibited higher ethane conversion. Moreover, a comparison of MgO–C-supported catalysts with MgO-supported catalysts revealed that the core–shell catalysts exhibited superior ethane conversion. Notably, the 5Mo@MgO–C catalyst demonstrated exceptional catalytic activity, achieving a high ethane conversion rate of 72% along with excellent stability. [ABSTRACT FROM AUTHOR]

A series of KF/Mg‐Fe oxides were fabricated via the solid‐state reaction between KF and Mg‐Fe oxides. Especially, when 20 wt % KF was supported on the Mg‐Fe bi‐metal oxides and calcined at 400–600 °C, the solid material with more basic sites than the support itself was obtained. When applied as catalyst to dimethyl carbonate (DMC) synthesis through transesterification of ethylene carbonate (EC) and methanol, this material can afforded up to 88 % yield and 97 % selectivity toward DMC in 2 h under reflux conditions with the molar ratio of methanol to ethylene carbonate set at 8. It is worth noting that the catalyst was easily separated and reused, retaining at least 89 % catalytic activity during the first four recycles. Although an attenuated activity was still observed due to the inevitable filtration loss and dissolution, this solid base can still provide clues to the development recyclable catalyst in green synthesis of DMC. [ABSTRACT FROM AUTHOR]

The oxidative carbonylation of methanol to synthesize dimethyl carbonate (DMC) has been extensively studied over Cu‐based catalysts, but the activity and selectivity are not high. The Co catalysts exhibit high DMC selectivity, but the difficulty in recycling homogeneous Co catalyst and the low conversion of heterogeneous Co catalyst limit the application of Co catalysts. Here, the core–shell ZIFs materials were synthesized and carbonized to obtain solid core–shell cobalt catalysts, and then the catalytic performance for methanol conversion to DMC was investigated. The CoNC@NC catalyst, carbonized from Z67@Z8 with Z67 as the core and Z8 as the shell, shows that the carbonized NC shell effectively suppressed the aggregation of Co NPs and the Co NPs were only 15.4 nm, which was much smaller than those of NC@CoNC (34.5 nm) and CoNC (48.1 nm) catalysts. Compared with the CoNC catalyst, CoNC@NC significantly improved the pulse chemisorption of CH3OH and CO, leading to a significant increase in methanol conversion from 6.9% to 17.1%. Furthermore, the deactivation rate of the CoNC@NC catalyst (22.8%) was much lower than that of CoNC (59.4%) after five reaction cycles. The results of this work provide a new strategy for the design and preparation of solid cobalt catalysts for the oxidative carbonylation of methanol to DMC. [ABSTRACT FROM AUTHOR]

Cu/SiO2 catalysts were prepared by co-precipitation (CP), hydrothermal (HT), ammonia evaporation (AE), and sol–gel (SG) methods and tested for their performance in the dehydrogenation reaction of secondary butyl alcohol to methyl ethyl ketone. The results showed that the Cu/SiO2 catalyst prepared by the sol–gel method has the best performance. By BET and H2–TPR characterization, it can be found that the catalysts prepared by sol–gel method has the largest specific surface areas and lowest reduction temperatures. Based on the characterization results of XRD, XPS and XAES, it shows that the catalyst prepared by sol–gel method has a better dispersion of copper components and a higher content of Cu0 species after reduction, which leads to its higher catalytic activity. At a copper loading of 22.96% (w%), the conversion of secondary butyl alcohol was up to 99.0% and the selectivity of methyl ethyl ketone was up to 99.8% by using the Cu/SiO2 catalysts prepared by sol–gel (SG) methods. [ABSTRACT FROM AUTHOR]

This work studied the one-step conversion of ethane (C2H6) to ethylene oxide (EO) in an AC parallel plate dielectric barrier discharge (DBD) system with two frosted glass plates under ambient temperature and atmospheric pressure. EO is directly produced from C2H6 in a single step without the requirement to separate and recycle ethylene. The effects of the applied voltage, input frequency, and O2/C2H6 feed molar ratio on the EO synthesis performance were examined. The results showed that a higher applied voltage and lower input frequency generated more highly energetic electrons, resulting in a higher current. More electrons collided with reactant gas molecules to initiate plasma reactions, increasing C2H6 and O2 conversions. The increased O2/C2H6 feed molar ratio enhanced C2H6 and O2 conversions. The optimum conditions were found to be an applied voltage of 7 kV, input frequency of 550 Hz, and O2/C2H6 feed molar ratio of 1:1, which demonstrated the highest EO selectivity (42.6%), EO yield (19.4%), and lowest power consumption per EO molecule produced (6.7 x 10-18 Ws/molecule). [ABSTRACT FROM AUTHOR]

Densities (ρ ) and viscosities (η ) of the binary mixtures of 2-ethyl-1-hexanol (2-EH) with ethylenediamine, 1,2-dichloroethane (DCE) and monoethanolamine (MEA) were measured at T = (298.15–318.15) K under atmospheric pressure over the entire composition range ( x 1 = 0 - 1.0 ). For these binary mixtures ultrasonic speeds (u ) and refractive indices ( n D ) were also measured at 298.15 K. With these experimental data the excess molar volumes ( V m E ), viscosity deviations ( Δ η ), excess molar refractions ( R m E ), excess isentropic compressibility ( κ S E ) and other derived properties were determined at various experimental temperatures. Such thermophysical properties were discussed in terms of molecular interactions and structural effects well corroborated with IR spectra of the mixtures. Excess molar volumes ( V m E ) of the binary mixtures were used to derive partial molar volumes ( V ¯ m,1 0 and V ¯ m, 2 0 ) and excess partial molar volumes ( V ¯ m,1 0,E and V ¯ m,2 0,E ) at infinite dilution to reveal the volume changes of the binary mixtures. Prigogine-Flory-Paterson theory (PFP), Peng-Robinson Equation of States (PR-EOS) and Bloomfield-Dewan (BF-D) model were used to predict excess molar volumes ( V m E ) and viscosities (η ) of the mixtures. Ultrasonic speeds (u ) of the binary mixtures predicted using empirical or semi-empirical theories like free length theory, Impedance dependence relation, Ideal mixture relation, Junjie's relation, collision factor theory and Nomoto's relation, etc. Computational studies have also been performed to establish the degree and nature of solvent–solvent interactions theoretically. [ABSTRACT FROM AUTHOR]

Electrification of adsorption processes is emerging as an adaptable solution for future gas separations. This study develops magnetic sorbent structures for use in induction vacuum swing adsorption (IVSA) process specifically designed for olefin/paraffin separation. Two sorbents, namely Fe3O4/ZIF‐7 (ethane‐selective) and Fe3O4/13X (ethylene‐selective) were developed and formulated into extrudates (Fe20/ZIF‐7‐P) and monoliths (Fe20/13X‐M), and tested under different regeneration scenarios, including simultaneous and subsequent induction‐evacuation, induction only, and evacuation only. The dynamic adsorption results demonstrated that regeneration under subsequent induction‐evacuation improves desorption rate and capability. Under this regeneration scenario, Fe20/ZIF‐7‐P achieved an ethane desorption rate of 0.24 mmol/g.min, representing a remarkable 37.5% enhancement over the induction‐only scenario. Similarly, Fe20/13X‐M exhibited an ethylene desorption rate of 0.35 mmol/g.min, indicative of a 34.2% enhancement. Moreover, the IVSA cyclic runs highlighted the excellent regeneration capability and stability of both Fe20/ZIF‐7‐P and Fe20/13X‐M with Fe20/13X‐M exhibiting ethylene purity, recovery, and productivity of 99.4%, 99.6%, and 39.9 mol/kg.h, respectively. Overall, these findings underscore the potential of the hybrid induction/vacuum process as an effective technique for achieving efficient regeneration of sorbents in olefin/paraffin separation. [ABSTRACT FROM AUTHOR]

Biodegradation of 1,4-Dioxane at environmentally relevant concentrations usually requires the addition of a primary electron-donor substrate to sustain biomass growth. Ethane is a promising substrate, since it is available as a degradation product of 1,4-Dioxane's common co-contaminants. This study reports kinetic parameters for ethane biodegradation and co-oxidations of ethane and 1,4-Dioxane. Based on experiments combined with mathematical modeling, we found that ethane promoted 1,4-Dioxane biodegradation when the initial mass ratio of ethane:1,4-Dioxane was < 9:1 mg COD/mg COD, while it inhibited 1,4-Dioxane degradation when the ratio was > 9:1. A model-independent estimator was used for kinetic-parameter estimation, and all parameter values for 1,4-Dioxane were consistent with literature-reported ranges. Estimated parameters support competitive inhibition between ethane as the primary substrate and 1,4-Dioxane as the secondary substrate. The results also support that bacteria that co-oxidize ethane and 1,4-Dioxane had a competitive advantage over bacteria that can use only one of the two substrates. The minimum concentration of ethane to sustain ethane-oxidizing bacteria and ethane and 1,4-Dioxane-co-oxidizing bacteria was 0.09 mg COD/L, which is approximately 20-fold lower than the minimum concentration reported for propane, another common substrate used to promote 1,4-Dioxane biodegradation. The minimum 1,4-Dioxane concentration required to sustain steady-state biomass with 1,4-Dioxane as the sole primary substrate was 1.3 mg COD/L. As 1,4-Dioxane concentrations at most groundwater sites are less than 0.18 mg COD/L, providing ethane as a primary substrate is vital to support biomass growth and consequently enable 1,4-Dioxane bioremediation. [ABSTRACT FROM AUTHOR]

Light-driven oxidative coupling of methane (OCM) for multi-carbon (C2+) product evolution is a promising approach toward the sustainable production of value-added chemicals, yet remains challenging due to its low intrinsic activity. Here, we demonstrate the integration of bismuth oxide (BiOx) and gold (Au) on titanium dioxide (TiO2) substrate to achieve a high conversion rate, product selectivity, and catalytic durability toward photocatalytic OCM through rational catalytic site engineering. Mechanistic investigations reveal that the lattice oxygen in BiOx is effectively activated as the localized oxidant to promote methane dissociation, while Au governs the methyl transfer to avoid undesirable overoxidation and promote carbon-carbon coupling. The optimal Au/BiOx-TiO2 hybrid delivers a conversion rate of 20.8 millimoles per gram per hour with C2+ product selectivity high to 97% in the flow reactor. More specifically, the veritable participation of lattice oxygen during OCM is chemically looped by introduced dioxygen via the Mars-van Krevelen mechanism, endowing superior catalyst stability. [ABSTRACT FROM AUTHOR]

The long‐term trends and seasonality of many tropospheric pollutants are not well characterized in the high Arctic due to a dearth of trace‐gas measurements in this remote region. In this study, the inter‐ and intra‐annual variabilities of carbon monoxide (CO), acetylene (C2H2), ethane (C2H6), methanol (CH3OH), formaldehyde (H2CO), formic acid (HCOOH), and peroxyacetyl nitrate (PAN) in the high Arctic region were derived from the total column time‐series of ground‐based Fourier transform infrared (FTIR) measurements at Eureka, Nunavut (80.05°N, 86.42°W, 2006–2020) and Thule, Greenland (76.53°N, 68.74°W, 1999–2022). Consistent seasonal cycles were observed in the FTIR measurements at both sites for all species. Negative trends were observed for CO, C2H2, and CH3OH at both sites, and for HCOOH at Eureka. Positive trends were detected for C2H6 and H2CO at both sites, and for PAN at Eureka. Additionally, a 19‐year simulation was performed using the novel GEOS‐Chem High Performance model v14.1.1 for the period of 2003–2021. The model was able to reproduce the observed seasonality of all gases, but all species showed negative biases relative to observations, and CH3OH was found to have a particularly large bias of approximately −70% relative to the FTIR measurements. The GEOS‐Chem modeled trends broadly agreed with observations for all species except C2H6, H2CO, and PAN, which were found to have opposite trends in the model. For some species, the measurement‐model differences are suspected to be the result of errors or underestimations in the emissions inventories used in the simulation. Plain Language Summary: In this study, we investigate the seasonality and long‐term trends of seven atmospheric pollutants measured from ground‐based spectrometers at two locations in the North American high Arctic; Eureka, Nunavut (80.05°N, 86.42°W, 2006–2020), and Thule, Greenland (76.53°N, 68.74°W, 1999–2022). We observe consistent seasonal cycles at both sites for all gases. Carbon monoxide and acetylene were found to be decreasing over the years at both locations, while others gases, like ethane and formaldehyde were steadily increasing. At Eureka, formic acid concentrations were also found to be steadily decreasing. To better understand these changes, we used a chemical transport model to simulate the behavior of these gases in the high Arctic over a 19‐year period (2003–2021). The model broadly captured the shape of the seasonal cycles, however, the simulation displayed some discrepancies relative to the ground‐based measurements. For some gases, such as methanol and peroxyacetyl nitrate, the model showed greater discrepancies with the measurements than for others. The model reproduced the observed trends for all species except ethane, formaldehyde, and peroxyacetyl nitrate, which were found to have opposite trends in the model. Some of these discrepancies are believed to be attributed to errors in the model's emissions inventories. Key Points: Consistent seasonal cycles were observed for seven tropospheric pollutants from the measurements of two high Arctic ground‐based FTIRsCO, C2H2, and CH3OH showed clear negative trends in the Arctic, while C2H6 and PAN displayed positive trendsGEOS‐Chem High Performance reproduced the observed trends of CO, C2H2, and CH3OH, but showed differing trends for C2H6, H2CO, and PAN [ABSTRACT FROM AUTHOR]

Organic electrolytes with Li+ were analyzed by far-ultraviolet (≤200 nm) spectroscopy, achieved by an attenuated total reflectance setup. The spectra showed a redshift with Li+ addition, attributed to the charge transfer, as revealed by quantum chemical calculations. Multivariate analysis successfully decomposed the spectra into pure solvent and Li-coordinated solvent components. [ABSTRACT FROM AUTHOR]

The interplay of host‐guest interactions and controlled modulation of spin‐crossover (SCO) behavior is one of the most exploited topics regarding data storage, molecular sensing, and optical technologies. This study examines the effect of solvents on the spin‐crossover (SCO) behavior of manganese(III) complexes [Mn(sal‐N‐1,5,8,12)]I•S (S=CH3OH, C2H5OH, CH3CN) (1) and [Mn(sal‐N‐1,5,8,12)]I3 (2), where (sal‐N‐1,5,8,12)2− is 2,2′‐((1E,13E)‐2,6,9,13‐tetraazatetradeca‐1,13‐diene‐1,14‐diyl)diphenol synthesized by salicylaldehyde and 1,2‐bis(3‐aminopropylamino)ethane. The complexes, crystallizing in orthorhombic or monoclinic systems, exhibit similar supramolecular arrangements with one‐dimensional cationic chains at low temperatures. Magnetic studies reveal that solvent inclusion sharpens the SCO transition and lowers the transition temperature. Specifically, 1⋅CH3OH shows a 13 K thermal hysteresis due to methanol's mobility through the channels in the cationic framework. Although the solvent‐free compound was not obtained, compound 2 with a linear I3− anion was synthesized, displaying extensive cation‐anion contacts and a distinct 13 K thermal hysteresis upon heating due to altered intermolecular cooperativity. This emphasizes the significant role of solvent introduction and variation in crystal packing and their impact on the SCO properties. [ABSTRACT FROM AUTHOR]

Direct determination of the equilibrium adsorption and spectroscopic observation of adsorbent‐adsorbate interaction is crucial to evaluate the olefin/paraffin separation performance of porous adsorbents. However, the experimental characterization of competitive adsorption of various adsorbates at atomic‐molecular level in the purification of multicomponent gas mixtures is challenging and rarely conducted. Herein, solid‐state NMR spectroscopy is employed to examine the effect of co‐adsorbed guest adsorbates on the separation of ethylene/ethane mixtures on Mg‐MOF‐74, Zn‐MOF‐74 and UTSA‐74. 1H MAS NMR facilitates the determination of equilibrium uptake and adsorption selectivity of ethylene/ethane in ternary mixtures. The co‐adsorption of H2O and CO2 significantly leads to the degradation of ethylene uptake and ethylene/ethane selectivity. The detailed host‐guest and guest‐guest interactions are unraveled by 2D 1H−1H spin diffusion homo‐nuclear correlation and static 25Mg NMR experiments. The experimental results verify H2O coordinated on open metal sites can supply a new adsorption site for ethylene and ethane. The effects of guest adsorbates on the adsorption capacity and adsorption selectivity of ethylene/ethane mixtures are in the following order: H2O>CO2>O2. This work provides a direct approach for exploring the equilibrium adsorption and detailed separation mechanism of multicomponent gas mixtures using MOFs adsorbents. [ABSTRACT FROM AUTHOR]

It is found that the reaction of dimethyl 2-phenylcyclopropane-1,1-dicarboxylate with 2 equivalents each of aromatic aldehydes and TaCl5 in 1,2-dichloroethane at 23 °C for 24 h after hydrolysis gives substituted 4-phenyl-3,4-dihydronaphtalene-2,2(1H)-dicarboxylates in good yield. This represents a new type of reactions between 2-arylcyclopropane-1,1-dicarboxylates and aromatic aldehydes, yielding chlorinated tetrahydronaphthalenes with a cis arrangement of the aryl and chlorine substituents in the cyclohexene moiety. A plausible reaction mechanism is proposed. [ABSTRACT FROM AUTHOR]

The distribution of stable isotopes in organic compounds within geochemical systems reflects the reactions they undergo, which are often kinetically governed and can be elucidated through quantification based on first principles: employing quantum chemical simulations to derive energy barriers and kinetic isotope effects (KIEs), followed by kinetic calculations using these parameters. In this paper, the distribution of 13C in hydrocarbon gases during the thermal generation and decomposition of ethane and propane has been addressed. The work is based on abundant and systematic isotopic data, including the compound- and position-specific 13C compositions, recent improvements in kinetic networks in hydrocarbon generation, and state-of-the-art quantum chemical methods that can process organic geochemical systems involving solid phases. Density Functional Theory computations validate the carbonium path of hydrocarbon generation and the free-radical path of their decomposition under geological conditions. The first step of each path (alkyl sidechain protonation for generation and hydrogen abstraction for decomposition) is the rate-limiting step and determines the 13C fractionations of gaseous hydrocarbons, with the reaction rate constrained by the concentration or accessibility of the active species (hydrated protons and surface free radicals in the two paths, respectively). Alkyl protonation has normal 13C KIEs, but hydrogen abstraction on the surfaces of solid organic matter has inverse ones (substituting 12C by 13C accelerates the reaction). These inverse KIEs explain three isotopic phenomena in gaseous hydrocarbons in their late thermal evolution: 1) the depletion of 13C in ethane and propane accompanied by their decreased fraction in hydrocarbon gases (isotope "rollover"); 2) the reversed 13C sequence with carbon number (δ13C methane > δ13C ethane > δ13C propane); and 3) the depletion of 13C in the center carbon atoms of residual propane. Isotopic fractionation between gaseous hydrocarbons upon generation is evaluated using the Successive Random Chain-Scission model. The covariation of δ13C in alkanes shows a depletion in CH 4 compared with the values expected from the reciprocal of the carbon numbers, indicating that this deviation may be intrinsic instead of mixing with microbial methane. The comparison of intramolecular 13C fractionation of propane between computational and observed data suggests the contribution of isoprenoids at the beginning of the generation, in addition to isotopic homogenization between the center and end carbon atoms through the ring closure of intermediate cations. The 13C–13C clumping exhibits a weak KIE in both the generation and decomposition of ethane; the clumping is essentially stochastically governed. This work demonstrates how first-principle calculations can provide significant insights into the details of geochemical reactions governing the isotopic distributions. [ABSTRACT FROM AUTHOR]

Industrial-scale production of acetaldehyde relies heavily on homogeneous catalysts. Here, we used ethane as the feedstock and developed ZSM-5-supported PdO nanoparticles for the direct oxidation of ethane to acetaldehyde by utilizing O2 and CO. PdO nanoparticles clearly demonstrate effective activity and prevent the further deep oxidation of acetaldehyde. [ABSTRACT FROM AUTHOR]

Collision‐induced dissociation (CID) of the mass‐selected cation [(bipy)Pt(CH3)2(CH2SCH3)]+ in an ion‐trap mass‐spectrometer results in the losses of the neutrals ethane, ethene, dimethyl sulfide, methane, ethyl methyl sulfide, and propane. The generation of the first four neutrals is also observed, when the isolated, dimeric complex [(bipy)Pt(CH3)2(CH2SCH3)]2[SbF6]2 is heated in the condensed phase. While the product distribution is very similar regardless of whether the complex is heated in the solid state or in solution, ethane loss, i. e. the quite rare event of an sp3‐sp3 C−C reductive elimination from a platinum(IV) complex, dominates in the gas‐phase experiment. However, when the counter anion [SbF6]− is exchanged by the more weakly coordinating anion [BAr4F]−, the amounts of ethane and ethene are increased also in the condensed phase. These sum of observations indicates the similarities of the fragmentation of [(bipy)Pt(CH3)2(CH2SCH3)]+ in both phases. Thus, a correlation of processes in both environments is possible for selected systems (and particularly for unimolecular processes), but the choice of the proper conditions is crucial for a meaningful comparison. [ABSTRACT FROM AUTHOR]

Collision‐induced dissociation (CID) of the mass‐selected cation [(bipy)Pt(CH3)2(CH2SCH3)]+ in an ion‐trap mass‐spectrometer results in the losses of the neutrals ethane, ethene, dimethyl sulfide, methane, ethyl methyl sulfide, and propane. The generation of the first four neutrals is also observed, when the isolated, dimeric complex [(bipy)Pt(CH3)2(CH2SCH3)]2[SbF6]2 is heated in the condensed phase. While the product distribution is very similar regardless of whether the complex is heated in the solid state or in solution, ethane loss, i. e. the quite rare event of an sp3‐sp3 C−C reductive elimination from a platinum(IV) complex, dominates in the gas‐phase experiment. However, when the counter anion [SbF6]− is exchanged by the more weakly coordinating anion [BAr4F]−, the amounts of ethane and ethene are increased also in the condensed phase. These sum of observations indicates the similarities of the fragmentation of [(bipy)Pt(CH3)2(CH2SCH3)]+ in both phases. Thus, a correlation of processes in both environments is possible for selected systems (and particularly for unimolecular processes), but the choice of the proper conditions is crucial for a meaningful comparison. [ABSTRACT FROM AUTHOR]

Diesel fuel and corn oil are mixed in the 80:20 volumetric ratio. Dimethyl carbonate and gasoline are added to diesel fuel + corn oil blend in 4:96, 6:94, 8:92, and 10:90 volumetric ratios to obtain ternary blends. Effects of ternary blends on the performance and combustion characteristics of a diesel engine are investigated under different engine speeds (1000–2500 rpm). 3D Lagrange interpolation method is applied to measured data of dimethyl carbonate blends to predict the engine speed, blending ratio, and crank angle giving maximum peak pressure and peak heat release rate. On average, dimethyl carbonate blends and gasoline blends show 4.3642–12.1578% and 1.0323–8.6843% reduction in effective power, and 1.4938–3.4322% and 4.3357–8.7188% reduction in effective efficiency, respectively, relative to diesel fuel. On average, there is a reduction in cylinder peak pressure (4.6701–7.3418%; 4.0457–6.2025%) and peak heat release rate (0.8020–4.5627%; 0.4–1.2654%) for dimethyl carbonate blends and gasoline blends, respectively, compared to diesel fuel. Because of low relative errors (1.0551% and 1.4553%), 3D Lagrange provides well accuracy in the prediction of maximum peak pressure and peak heat release rate. On average, dimethyl carbonate blends produce less CO (7.4744–17.5424%), HC (15.5410–29.5501%) and smoke (14.1767–25.2834%) emissions, compared with diesel fuel. [ABSTRACT FROM AUTHOR]