A Crystalline-Water Electrolyte Enabled High Depth-of-Discharge Anodes in Aqueous Zinc Metal Batteries.

Aqueous zinc metal batteries are regarded as a promising energy storage solution for a green and sustainable society in the future. However, the practical application of metallic zinc anode is plagued by the thermodynamic instability issue of water molecules in conventional electrolytes, which leads to severe dendrite growth and side reactions. In this work, an ultra-thin and high areal capacity metallic zinc anode is achieved by utilizing crystalline water with a stable stoichiometric ratio. Unlike conventional electrolytes, the designed electrolyte can effectively suppress the reactivity of water molecules and diminish the detrimental corrosion on the metallic zinc anode, while preserving the inherent advantages of water molecules, including great kinetic performance in electrolytes and H+ capacity contribution in cathodes. Based on the comprehensive performance of the designed electrolyte, the 10 µm Zn||10 µm Zn symmetric cell stably ran for 1000 h at the current density of 1 mA cm-2, and the areal capacity of 1 mAh cm-2, whose depth-of-discharge is over 17.1%. The electrochemical performance of the 10 µm Zn||9.3 mg cm-2 polyaniline (PANI) full-cell demonstrates the feasibility of the designed electrolyte. This work provides a crucial understanding of balancing activity of water molecules in aqueous zinc metal batteries.

Lipidomic Profiling and Pharmacological Activities of Ficus drupacea Oil: Comparative Study Between Conventional vs. Green Solvent.

Ficus drupacea is a medicinal tree found in temperate regions. Various parts of this plant had been used traditionally for the treatment of various ailments such as root powder applied externally for skin infections. Analysis was carried out on the bioactive lipids extracted from Ficus drupacea fruit using both petroleum-based solvent (Hexane) and an environmentally friendly solvent Dimethyl carbonate (DMC). The results showed that DMC extraction yielded a high oil content in Ficus drupacea fruit (6.51 %). When examining the fatty acid composition using GC-FID analysis, Ficus drupacea oil extracted with DMC contained significant proportions of essential fatty acids such as linoleic acid (32.317 %), oleic acid (20.946 %), palmitic acid (25.841 %), etc. Additionally, DMC extraction resulted in higher levels of total phenolics in Ficus drupacea fruit oil compared to hexane. Moreover, DMC extracted oil exhibited stronger antioxidant properties, such as radical scavenging, anti- arthritic, photoprotective activity while displayed similar anti-inflammatory and anti-microbial activity as hexane-extracted oil. In summary, these findings demonstrate that DMC is an efficient and safer alternative to conventional solvent hexane for extracting oils from Ficus drupacea fruit. It is rich in bioactive compounds essential for human nutrition, including polyunsaturated fatty acids, flavonoids, and phenolic compounds, with enhanced biological activities.

Polarized Active Pairs at Grain Boundary Boost CO2 Chemical Fixation.

The chemical fixation of CO2 as a C1 feedstock is considered one of the most promising ways to obtain long-chain chemicals, but its efficiency was limited by the ineffective activation of CO2. Herein, we propose a grain boundary engineering strategy to construct polarized active pairs with electron poor-rich character for effective CO2 activation. By taking CeO2 as a model system, we illustrate that the polarized "Ce4+-Ce3+-Ce4+" pairs at the grain boundary can simultaneously accept and donate electrons to coordinate with O and C, respectively, in CO2. By the combination of synchrotron radiation in situ technique and density functional theory calculations, the mechanism of the catalytic reaction has been systematically investigated. As a result, the CeO2 nanosheets with a rich grain boundary show a high DMC yield of 60.3 mmol/gcat with 100% atomic economy. This study provides a practical way for the chemical fixation of CO2 to high-value-added chemicals via grain boundary engineering.

Stabilization of Pd0 by Cu Alloying: Theory-Guided Design of Pd3Cu Electrocatalyst for Anodic Methanol Carbonylation.

Electrocatalytic carbonylation of CO and CH3OH to dimethyl carbonate (DMC) on metallic palladium (Pd) electrode offers a promising strategy for C1 valorization at the anode. However, its broader application is limited by the high working potential and the low DMC selectivity accompanied with severe methanol self-oxidation. Herein, our theoretical analysis of the intermediate adsorption interactions on both Pd0 and Pd4+ surfaces revealed that inevitable reconstruction of Pd surface under strongly oxidative potential diminishes its CO adsorption capacity, thus damaging the DMC formation. Further theoretical modeling indicates that doping Pd with Cu not only stabilizes low-valence Pd in oxidative environments but also lowers the overall energy barrier for DMC formation. Guided by this insight, we developed a facile two-step thermal shock method to prepare PdCu alloy electrocatalysts for DMC. Remarkably, the predicted Pd3Cu demonstrated the highest DMC selectivity among existing Pd-based electrocatalysts, reaching a peaked DMC selectivity of 93 % at 1.0 V versus Ag/AgCl electrode. (Quasi) in situ spectra investigations further confirmed the predicted dual role of Cu dopant in promoting Pd-catalyzed DMC formation.

Dimethyl Carbonate Synthesis from CO2 over CeO2 with Electron-Enriched Lattice Oxygen Species.

Direct synthesis of dimethyl carbonate (DMC) from CO2 plays an important role in carbon neutrality, but its efficiency is still far from the practical application, due to the limited understanding of the reaction mechanism and rational design of efficient catalyst. Herein, abundant electron-enriched lattice oxygen species were introduced into CeO2 catalyst by constructing the point defects and crystal-terminated phases in the crystal reconstruction process. Benefitting from the acid-base properties modulated by the electron-enriched lattice oxygen, the optimized CeO2 catalyst exhibited a much higher DMC yield of 22.2 mmol g-1 than the reported metal-oxide-based catalysts at the similar conditions. Mechanistic investigations illustrated that the electron-enriched lattice oxygen can provide abundant sites for CO2 adsorption and activation, and was advantageous of the formation of the weakly adsorbed active methoxy species. These were facilitating to the coupling of methoxy and CO2 for the key *CH3OCOO intermediate formation. More importantly, the weakened adsorption of *CH3OCOO on the electron-enriched lattice oxygen can switch the rate-determining-step (RDS) of DMC synthesis from *CH3OCOO formation to *CH3OCOO dissociation, and lower the corresponding activation barriers, thus giving rise to a high performance. This work provides insights into the underlying reaction mechanism for DMC synthesis from CO2 and methanol and the design of highly efficient catalysts.

Boosting Activity and Selectivity of UiO-66 through Acidity/Alkalinity Functionalization in Dimethyl Carbonate Catalysis.

The acid-base properties of supports have an enormous impact on catalytic reactions to regulate the selectivity and activity of supported catalysts. Herein, a train of Pd-X-UiO-66 (X = NO2 , NH2 , and CH3 ) catalysts with different acidity/alkalinity functional groups and encapsulated Pd(II) species is first developed, whose activities in dimethyl carbonate (DMC) catalysis are then investigated in details. Thereinto, the Pd-NO2 -UiO-66 catalyst with acidity functionalization exhibits the best catalytic behavior: the DMC selectivity stemmed from methyl nitrite (MN) is up to 68%, the conversion of CO is 73.4%. The obtained experimental results demonstrate that the NO2 group not only affected the interaction between X-UiO-66 and Pd(II) active sites but also play an indispensable role in the adsorption and activation of MN and CO, which remarkably promote the formation of the COOCH3 * intermediate and DMC product.

Studies on the Prediction and Extraction of Methanol and Dimethyl Carbonate by Hydroxyl Ammonium Ionic Liquids.

The separation of dimethyl carbonate (DMC) and methanol is of great significance in industry. In this study, ionic liquids (ILs) were employed as extractants for the efficient separation of methanol from DMC. Using the COSMO-RS model, the extraction performance of ILs consisting of 22 anions and 15 cations was calculated, and the results showed that the extraction performance of ILs with hydroxylamine as the cation was much better. The extraction mechanism of these functionalized ILs was analyzed by molecular interaction and the σ-profile method. The results showed that the hydrogen bonding energy dominated the interaction force between the IL and methanol, and the molecular interaction between the IL and DMC was mainly Van der Waals force. The molecular interaction changes with the type of anion and cation, which in turn affects the extraction performance of ILs. Five hydroxyl ammonium ILs were screened and synthesized for extraction experiments to verify the reliability of the COSMO-RS model. The results showed that the order of selectivity of ILs predicted by the COSMO-RS model was consistent with the experimental results, and ethanolamine acetate ([MEA][Ac]) had the best extraction performance. After four regeneration and reuse cycles, the extraction performance of [MEA][Ac] was not notably reduced, and it is expected to have industrial applications in the separation of methanol and DMC.

Elucidating the Role of Surface Ce4+ and Oxygen Vacancies of CeO2 in the Direct Synthesis of Dimethyl Carbonate from CO2 and Methanol.

Cerium dioxide (CeO2) was pretreated with reduction and reoxidation under different conditions in order to elucidate the role of surface Ce4+ and oxygen vacancies in the catalytic activity for direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol. The corresponding catalysts were comprehensively characterized using N2 physisorption, XRD, TEM, XPS, TPD, and CO2-FTIR. The results indicated that reduction treatment promotes the conversion of Ce4+ to Ce3+ and improves the concentration of surface oxygen vacancies, while reoxidation treatment facilitates the conversion of Ce3+ to Ce4+ and decreases the concentration of surface oxygen vacancies. The catalytic activity was linear with the number of moderate acidic/basic sites. The surface Ce4+ rather than oxygen vacancies, as Lewis acid sites, promoted the adsorption of CO2 and the formation of active bidentate carbonates. The number of moderate basic sites and the catalytic activity were positively correlated with the surface concentration of Ce4+ but negatively correlated with the surface concentration of oxygen vacancies. The surface Ce4+ and lattice oxygen were active Lewis acid and base sites respectively for CeO2 catalyst, while surface oxygen vacancy and lattice oxygen were active Lewis acid and base sites, respectively, for metal-doped CeO2 catalysts. This may result from the different natures of oxygen vacancies in CeO2 and metal-doped CeO2 catalysts.

Application of Green Chiral Chromatography in Enantioseparation of Newly Synthesized Racemic Marinoepoxides.

Enantioseparation of the newly synthesized series of novel quinoline-2(1H)-one epoxide structures rac-6a-c and rac-8a-c, named marinoepoxides, is described. Marinoepoxide rac-6a, the key intermediate in the total synthesis of natural products marinoaziridines A and B, as well as their structural analogues, was synthesized by addition of the achiral ylide generated in situ from the sulfonium salt 5 or 7, to the carbon-oxygen double bond of the corresponding quinoline-2(1H)-one-4-carbaldehyde 4a-c in good yield. Separation of enantiomers of (±)-2,3,3-trisubstituted marinoepoxides rac-6a-c and (±)-trans-2,3-disubstituted marinoepoxides rac-8a-c was studied using two immobilized polysaccharide type chiral stationary phases (CSPs); tris-(3,5-dichlorophenylcarbamoyl)cellulose stationary phase (CHIRAL ART Cellulose-SC) and tris-(3,5-dimethylphenylcarbamoyl)amylose stationary phase (CHIRAL ART Amylose-SA). Enantioseparation conditions were explored by high-performance liquid chromatography (HPLC) using dimethyl carbonate/alcohol mixtures and n-hexane/ethanol (80/20, v/v) as mobile phase, and by supercritical fluid chromatography (SFC) using CO2/alcohol mixtures as mobile phase. In all examined racemates, enantioseparation was successfully achieved, but its efficiency largely depended on the structure of chiral selector and type/composition of the mobile phase.

Cobalt Element Effect of Ternary Mesoporous Cerium Lanthanum Solid Solution for the Catalytic Conversion of Methanol and CO2 into Dimethyl Carbonate.

A citric acid ligand assisted self-assembly method is used for the synthesis of ternary mesoporous cerium lanthanum solid solution doped with metal elements (Co, Zr, Mg). Their textural property was characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, X-ray photoelectron spectroscopy and TPD techniques, and so on. The results of catalytic testing for synthesis of dimethyl carbonate (DMC) from CH3OH and CO2 indicated that the DMC yield reached 316 mmol/g on Ce-La-Co solid solution when the reaction temperature was 413 K and the reaction pressure was 8.0 MPa. It was found that Co had synergistic effect with La and Ce, doping of Co on the mesoporous Ce-La solid solution was helpful to increase the surface area of the catalyst, promote CO2 adsorption and activation, and improve the redox performance of solid solution catalyst. The conversion of Co2+ to Co3+ resulted in the continuous redox cycle between Ce4+ and Ce3+, and the oxygen vacancy content of the catalyst was increased. Studies have shown that the catalytic performance of Ce-La-Co solid solution is positively correlated with oxygen vacancy content. On this basis, the reaction mechanism of DMC synthesis from CO2 and CH3OH on the catalyst was speculated.

New Strategies on Green Synthesis of Dimethyl Carbonate from Carbon Dioxide and Methanol over Oxide Composites.

Dimethyl carbonate is a generally used chemical substance which is environmentally sustainable in nature and used in a range of industrial applications as intermediate. Although various methods, including methanol phosgenation, transesterification and oxidative carbonylation of methanol, have been developed for large-scale industrial production of DMC, they are expensive, unsafe and use noxious raw materials. Green production of DMC from CO2 and methanol is the most appropriate and eco-friendly method. Numerous catalysts were studied and tested in this regard. The issues of low yield and difficulty in tests have not been resolved fundamentally, which is caused by the inherent problems of the synthetic pathway and limitations imposed by thermodynamics. Electron-assisted activation of CO2 and membrane reactors which can separate products in real-time giving a maximum yield of DMC are also being used in the quest to find more effective production method. In this review paper, we deeply addressed green production methods of DMC using Zr/Ce/Cu-based nanocomposites as catalysts. Moreover, the relationship between the structure and activity of catalysts, catalytic mechanisms, molecular activation and active sites identification of catalysts are also discussed.

Co-Production of Dimethyl Carbonate, Dimethoxymethane and Dimethyl Ether from Methanol: Process Design and Exergy Analysis.

Dimethyl carbonate is an important green chemical that has been widely used in the chemical industry. In the production of dimethyl carbonate, methanol oxidative carbonylation has been studied, but the conversion ratio of dimethyl carbonate using this method is too low, and the subsequent separation requires a large amount of energy due to methanol and dimethyl carbonate being azeotrope. In this paper, the strategy of "reaction instead of separation" is proposed. Based on this strategy, a novel process is developed to combine the production of DMC with that of dimethoxymethane (DMM) and dimethyl ether (DME). The co-production process was simulated using Aspen Plus software, and the product purity was up to 99.9%. The exergy analysis of the co-production process and the existing process was carried out. The exergy destruction and exergy efficiency were compared with those of the existing production processes. The results show that the exergy destruction of the co-production process is about 276% less than that of the single-production processes, and the exergy efficiencies in the developed co-production process are significantly improved. The utility loads of the co-production process are significantly lower than that of the single-production process. The developed co-production process increases the methanol conversion ratio to 95%, with a reduced energy requirement. It is proved that the developed co-production process can provide an advantageous option over the existing processes with improved energy efficiency and material savings. The strategy of "reaction instead of separation" is feasible. A new strategy is proposed for azeotrope separation.

Atom-Economical Synthesis of Dimethyl Carbonate from CO2 : Engineering Reactive Frustrated Lewis Pairs on Ceria with Vacancy Clusters.

The chemical conversion of CO2 to long-chain chemicals is considered as a highly attractive method to produce value-added organics, while the underlying reaction mechanism remains unclear. By constructing surface vacancy-cluster-mediated solid frustrated Lewis pairs (FLPs), the 100 % atom-economical, efficient chemical conversion of CO2 to dimethyl carbonate (DMC) was realized. By taking CeO2 as a model system, we illustrate that FLP sites can efficiently accelerate the coupling and conversion of key intermediates. As demonstrated, CeO2 with rich FLP sites shows improved reaction activity and achieves a high yield of DMC up to 15.3 mmol g-1 . In addition, by means of synchrotron radiation in situ diffuse reflectance infrared Fourier-transform spectroscopy, combined with density functional theory calculations, the reaction mechanism on the FLP site was investigated systematically and in-depth, providing pioneering insights into the underlying pathway for CO2 chemical conversion to long-chain chemicals.

Ultrathin In-Plane Heterostructures for Efficient CO2 Chemical Fixation.

Chemical fixation of carbon dioxide (CO2 ) into value-added organics is regarded as a competitive and viable method in large scale industrial production, during which the catalysts with promoting CO2 activation ability are needed. Herein, we proposed an in-plane heterostructure strategy to construct Lewis acid-base sites for efficient CO2 activation. By taking ultrathin in-plane Cu2 O/Cu heterostructures as a prototype, we show that Lewis acid-base sites on heterointerface can facilitate a mixed C and O dual coordination on surface, which not only strengthen CO2 adsorption, but also effectively activate the inert molecules. As revealed by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and quasi in situ X-ray photoelectron spectroscopy (XPS), Lewis acid-base sites could readily activate CO2 to . CO2 - species, which is the key intermediate radical for CO2 fixation. As a result, abundant Lewis acid-base sites endow Cu2 O/Cu nanosheets with excellent performances for dimethyl carbonate generation, a high conversion yield of 28 % with nearly 100 % selectivity under mild conditions. This study provides a model structure for CO2 fixation reactions.

Co-transesterification of waste cooking oil, algal oil and dimethyl carbonate over sustainable nanoparticle catalysts.

Key challenges for the application of biodiesel include their high acid value, high viscosity, and low ester content. It is essential to develop later-generation biodiesel from unexploited non-food resources for a more sustainable future. Reuse of biowaste is critically important to address these issues of food safety and sustainability. Thus, the co-transesterification of waste cooking oil (WCO), algal oil (AO) and dimethyl carbonate (DMC) for the synthesis of fatty acid methyl esters (FAMEs) was investigated over a series of nanoparticle catalysts containing calcium, magnesium, potassium or nickel under mild reaction conditions. Nanoparticle catalyst samples were prepared from biowaste sources of chicken manure (CM), water hyacinth (WH) and algal bloom (AB), and characterized using XRD, Raman and FESEM techniques for the heterogeneous production of biodiesel. The catalyst was initially prepared by calcination at 850 °C for 4 h in a major presence of CaxMgyCO3, KCl and K2CO3. The WCO and AO co-conversion of 98% and FAMEs co-selectivity of 95% were obtained over CM nanoparticle catalyst under the reaction conditions of 80 °C, 20 mins and DMC to oil molar ratio of 6:1 with 3% catalyst loading and 3% methanol addition. Under the optimum condition, the density, viscosity, and cetane number of the biodiesel were in the range of diesel standards. Nanoparticle catalysts have been proven as a promising sustainable material in the catalytic transesterification of WCO and AO with the major presence of calcium, magnesium and potassium. This study highlights a sustainable approach via biowaste utilization for the enhancement of biodiesel quality with high ester content, low acid value, high cetane number, and low viscosity.

Engine performance and emission characteristics of palm biodiesel blends with graphene oxide nanoplatelets and dimethyl carbonate additives.

This study investigated the engine performance and emission characteristics of biodiesel blends with combined Graphene oxide nanoplatelets (GNPs) and 10% v/v dimethyl carbonate (DMC) as fuel additives as well as analysed the tribological characteristics of those blends. 10% by volume DMC was mixed with 30% palm oil biodiesel blends with diesel. Three different concentrations (40, 80 and 120 ppm) of GNPs were added to these blends via the ultrasonication process to prepare the nanofuels. Sodium dodecyl sulphate (SDS) surfactant was added to improve the stability of these blends. GNPs were characterised using Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR), while the viscosity of nanofuels was investigated by rheometer. UV-spectrometry was used to determine the stability of these nanoplatelets. A ratio of 1:4 GNP: SDS was found to produce maximum stability in biodiesel. Performance and emissions characteristics of these nanofuels have been investigated in a four-stroke compression ignition engine. The maximum reduction in BSFC of 5.05% and the maximum BTE of 22.80% was for B30GNP40DMC10 compared to all other tested blends. A reduction in HC (25%) and CO (4.41%) were observed for B30DMC10, while a reduction in NOx of 3.65% was observed for B30GNP40DMC10. The diesel-biodiesel fuel blends with the addition of GNP exhibited a promising reduction in the average coefficient of friction 15.05%, 8.68% and 3.61% for 120, 80 and 40 ppm concentrations compared to B30. Thus, combined GNP and DMC showed excellent potential for utilisation in diesel engine operation.

Chemical Adsorption Strategy for DMC-MeOH Mixture Separation.

The effective separation of dimethyl carbonate (DMC) from its methanol mixture through simple, inexpensive and low energy-input method is a promising and challenging field in the process of organic synthesis. Herein, a reversible adsorption strategy through the assistance of superbase and CO2 for DMC/methanol separation at ambient condition was described. The process was demonstrated effectively via the excellent CO2 adsorption efficiency. Notably, the protocol was also suitable to other alcohol (i.e., monohydric alcohol, dihydric alcohol, trihydric alcohol) mixtures. The study provided guidance for potential separation of DMC/alcohol mixture in the scale-up production.

Single-Step Methylation of Chitosan Using Dimethyl Carbonate as a Green Methylating Agent.

N,N,N-Trimethyl chitosan (TMC) is one chitosan derivative that, because of its improved solubility, has been studied for industrial and pharmaceutic applications. Conventional methods for the synthesis of TMC involve the use of highly toxic and harmful reagents, such as methyl iodide and dimethyl sulfate (DMS). Although the methylation of dimethylated chitosan to TMC by dimethyl carbonate (DMC, a green and benign methylating agent) was reported recently, it involved a formaldehyde-based procedure. In this paper we report the single-step synthesis of TMC from chitosan using DMC in an ionic liquid. The TMC synthesised was characterised by 1H NMR spectroscopy and a functionally meaningful degree of quaternisation of 9% was demonstrated after a 12-h reaction time.

Compressed-liquid Densities of the Binary Mixture Dimethyl Carbonate + Heptane at Three Compositions.

Compressed-liquid densities of the binary system dimethyl carbonate + heptane have been measured with a vibrating-tube densimeter over the temperature and pressure ranges of 270 K to 470 K, and 1 MPa to 50 MPa at three compositions of the mixture. The measurements are part of an effort to better understand the molecular interactions of polar/non-polar mixtures. These types of mixtures often exhibit very non-ideal behavior. By measuring the mixture at three compositions and over a large range of temperature and pressure, the non-ideality can be assessed. There are no high-pressure liquid density data for this binary system in the literature, thus data reported here could only be compared to literature data at atmospheric pressure to establish their quality. The majority of literature data agree well with the presented results which have a maximum expanded uncertainty of 1.63 kg·m-3 (for the composition with the greatest mole fraction of dimethyl carbonate). The non-ideality for the mixture, in the temperature, pressure and composition range of this study was found to be minimal. This is rationalized by considering the molecular sizes, shapes, and charge distributions of the pure components and the attractive parts of their intermolecular force fields as they are reflected in the temperature ranges of their vapor pressure curves.

Soot reduction by addition of dimethyl carbonate in normal and inverse ethylene diffusion flames: Nanostructural evidence.

Oxygenated fuel represents an attractive alternative as an additive for reducing soot emissions. Dimethyl carbonate (DMC) is an oxygenated compound which is a good option to reduce soot, but the detailed characteristics of soot produced from combustion of hydrocarbon fuels blended with DMC are still lacking. The present research studied the nanostructure and reactivity of soot particles in ethylene/DMC normal and inverse diffusion flames. High resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were used to analyze the nanostructure and reactivity of soot. It was found that DMC addition was effective in decreasing the average weights of soot formed in flames. The results of HRTEM images showed that soot particles obtained with DMC addition showed liquid-like material and tight bonding, and exhibited more highly disorganized layers, which give it higher reactivity than soot obtained without DMC addition. Furthermore, HRTEM was used to analyze soot fringe characteristics consisting of fringe tortuosity, fringe length, and fringe separation. XRD was used to crosscheck the results for fringe separation, and was consistent with HRTEM results. In addition, the mass loss curve of TGA experiments showed that DMC addition could enhance the reactivity of soot particles.