Dimethyl Carbonate Research Articles

Effects of fluorine and phosphorus-based flame retardants addition on the lower flammability limit of dimethyl carbonate

This study initially examines the alteration pattern of the lower flammable limit (LFL) of dimethyl carbonate (DMC), a typical electrolyte component in lithium batteries, under the influence of inhibitors, namely di(2,2,2trifluoroethyl) carbonate (DtFEC), perfluorohexanone (C6F12O), and trimethylphosphate (TMP), through experimental investigation. Additionally, the critical inhibitory concentration required for complete inhibition is investigated. Subsequently, numerical simulations and chemical kinetic path analyses reveal how these inhibitors control combustion. Results show that C6F12O and DtFEC initially decrease and then increase the LFL of DMC, while TMP causes a monotonic increase. This is due to the competition between reaction-thermal and reaction-radical effects. Reaction kinetic analysis reveal that when small amounts of C6F12O and DtFEC are added, the fluorine-containing components decomposed by the reaction undergo oxidation, thereby promoting combustion. However, with increased amounts, these components combine with H and OH radicals to form stable substances like HF, inhibiting the combustion process. In the case of TMP, the phosphorus-containing intermediate components produced by cleavage catalyze the recombination of H and OH radicals, thereby inhibiting DMC combustion. The research findings offer a theoretical foundation for the development of safer lithium batteries and provide crucial data references for enhancing battery safety and prevention measures.

Li-ion solvation structure at electrified solid-liquid interface: Understanding solvation structure dynamics and its role in electrochemical energy storage through binary ethylene carbonate and dimethyl carbonate solvent.

Binary solvent electrolytes can provide interpretations for designing advanced electrolytes of next generation batteries. This study investigates the adsorption mechanisms of solvated lithium ions in binary solvents near charged electrodes. Molecular dynamic simulations are performed for lithium hexafluorophosphate (LiPF6) in ethylene carbonate and dimethyl carbonate (EC:DMC) solvent sandwiched between two electrodes. Results show that lithium ions form a tetrahedral solvation structure with two EC and two DMC molecules. The solvated lithium ion shows anti-electrostatic interaction with electrodes. This can be attributed to the electrostatic attraction of the polar end of the DMC molecule, which keeps the cation anchored to the positive electrode. Meanwhile, the solvation structure adopts a fix orientation at the negative electrode, which leads to unchanged electrostatic interaction at high charge density. Finally, EC molecules are swapped by DMC molecules near the negative electrode at high charge density. This leads to a decrease in local relative permittivity and, therefore, a decrease in differential capacitance. The differential capacitance of the positive electrode continuously decreases with increasing charge density. This is caused by the partial anchoring of solvent molecules holding the cations, which cancels the adsorption of anions near the positive electrode. This study provides insights into designing better electrolytes for efficient battery performance.

Unveiling the low‐temperature oxidation chemistry of dipropyl carbonate

AbstractDialkyl carbonates (DACs) own an environmentally friendly synthesis route, making them potential candidates as alternative fuels. However, for DACs to be widely accepted as an alternative fuel, a comprehensive understanding of their combustion behavior is essential. Dipropyl carbonate (DPrC) represents a transition from short‐chain to mid‐chain carbonates, understanding its combustion behaviors holds significance in unraveling the combustion chemistry of carbonates. In this study, the oxidation of DPrC was investigated with the initial fuel mole fraction of 0.5% at three equivalence ratios of 0.5, 1.0, and 2.0 within a temperature range of 550–1100 K in a jet‐stirred reactor for the first time. Gas chromatography was utilized for the quantitative detection of reactants, intermediates, and products. A detailed DPrC mechanism was first developed, and good agreements between measurements and simulations were obtained. A notable negative temperature coefficient (NTC) behavior was first observed in the oxidation of DACs. Such NTC phenomenon occurred at fuel‐lean conditions in the temperature range of 620–660 K, while only a weak low‐temperature consumption was observed at the stoichiometric condition. Kinetic modeling studies showed that this unique low‐temperature chemistry of DPrC can be attributed to the differences in the RO2 isomerization reactions between DPrC and short‐chain DACs. The RO2 isomerization via a six‐member ring transition state could happen in DPrC oxidation but not in dimethyl carbonate and diethyl carbonate oxidation, due to the different fuel molecular structure. Therefore, the subsequent reaction pathways via QOOH → O2QOOH → HO2Q = O + OH → OQ = O + OH were promoted and two OH radicals were released in this process. Moreover, it is conceivable that mid or long‐chain DACs could also exhibit an NTC phenomenon due to the increased potential for RO2 isomerization via a six‐ or seven‐member ring transition state, thereby increasing the likelihood of RO2 isomerization occurrence.

Regulation of Surface Oxygen Vacancies on Ce-Based Catalysts for Dimethyl Carbonate Direct Synthesis from CO2 and CH3OH

Regulation of Surface Oxygen Vacancies on Ce-Based Catalysts for Dimethyl Carbonate Direct Synthesis from CO₂ and CH₃OH

Solvation Regulation via Hydrogen Bonding to Mitigate Al Current Collector Corrosion for High‐Voltage Li‐Ion Batteries

AbstractThe exceptional thermal stability and conductivity of lithium bis(fluorosulfonyl)imide (LiFSI) have made it a preferred salt for lithium‐ion batteries (LIBs). However, the corrosion of aluminum (Al) current collectors by LiFSI at low potentials (3.8 V vs Li/Li+) poses a persistent challenge, hindering the application of LiFSI in 4 V‐class LIBs. Herein, 2,2,2‐trifluoroethyl methanesulfonate (TFMS) is proposed as a versatile co‐solvent to address the issue of Al current collector corrosion. It is demonstrated that incorporating TFMS into a conventional LiFSI‐based carbonate electrolyte can precisely tailor the Li+ solvation structure by hydrogen bonding interactions with dimethyl carbonate (DMC) solvent. This weakens the coordination between DMC and Li+ while increasing the participation of FSI− anions in the primary solvation shell, effectively suppressing the Al current collector caused by free FSI− anions attacking. Furthermore, TFMS and FSI− synergically induce the formation of an inorganic‐rich and compact cathode electrolyte interphase, significantly avoiding undesired side reactions. As a result, the TFMS‐electrolyte enables 1.2 Ah‐graphite||NCM811 (LiNi0.8Co0.1Mn0.1O2) pouch‐cells to achieve 89.9% capacity retention with high average Coulombic efficiency of >99.9% for 200 cycles at a cut‐off voltage of 4.4 V, opening up opportunities for the development of advanced high‐voltage LIBs.

Contamination in LIB Pouch Cells Promoting Self‐Discharge and Crosstalk

AbstractStorage studies of lithium‐ion battery electrolyte within bags made of commercial pouch foils, commonly used as encasing material of battery cells, revealed the presence of contamination leaching from the pouch foil material into the electrolyte. By analyzing the stored electrolyte via GC‐MS the appearing compound was identified as 2,4‐di‐tert‐butylphenol (2,4‐DTBP). To investigate the influence of DTBP on the battery cell performance, full cells employing commercial LiNi1/3Mn1/3Co1/3O2 based cathodes and graphite‐type anodes were assembled using 1 M LiPF6 in ethylene carbonate/ dimethyl carbonate mixture as the electrolyte with/out the intentional addition of either 2,4‐DTBP or its constitutional isomer 2,6‐DTBP. Furthermore, dimethyl terephthalate (DMT), a literature known redox shuttle triggering impurity leaching from PET‐based fixing tape used in LIBs, was added to compare the effect of DMT to DTBPs. It was revealed that either DTBP contaminations have a significant impact on the self‐discharge behavior of the studied cells, which exceed the effect of present DMT. Moreover, all contaminants heavily increase transition metal dissolution‐migration‐deposition (TM DMD) processes and irreversible capacity loss. When vinylene carbonate, an SEI forming additive, is added to the electrolyte mixtures self‐discharge, as well as TM DMD are suppressed to a different degree depending on the type of contaminant added.

Substrate-Induced Cooperative Ionic Catalysis: Difunctionalization of Indole Derivatives Employing Dimethyl Carbonate.

The global urge to adopt sustainable chemistry has resulted in the development of more environmentally benign strategies (EBS) that use CO2 and CO2-derived chemicals in a step-economic manner. In this context, we investigated a dual C-H methylation and (C═O)-methoxylation of indole derivatives using dimethyl carbonate (DMC) in the presence of catalytic amounts of Cs2CO3. Mechanistic insights include DMF-assisted, DMC-induced cooperative ionic catalysis, which allows DMC to act as both a nucleophilic and an electrophilic precursor, resulting in (C═O)-methoxylation and C-H methylation of N-benzylindolyl ketones.

Sustainable C-H Methylation Employing Dimethyl Carbonate.

The use of CO2 and CO2-derived chemicals offers society sustainable and biocompatible chemistry for a variety of applications, ranging from materials to medicines. In this context, dimethyl carbonate (DMC) stands out owing to its low toxicity, high biodegradability, tunable reactivity, and sustainable production. Further, the ability of DMC to act as an ambient electrophile at varied temperatures and reaction conditions in order to produce methoxycarbonylated (via BAC2) and methylated products (via BAL2) is very promising. While the methylation of hetero-H (N-, O-, and S-methylation) with DMC is established and well-reviewed, the C-H methylation reaction with DMC is limited, and there is no specific literature detailing the C-methylation reaction using DMC, creating new opportunities as well as challenges in the same domain. In this context, the present perspective focuses on the new breakthroughs, recent advances, and trends in C-H methylation reactions employing DMC. A critical analysis of the mechanistic course of reactions under each category was undertaken. We believe this timely perspective will offer an in-depth analysis of existing literature with critical remarks, which will certainly inspire fellow researchers across disciplines to understand and pursue cutting-edge research in the area of C-H methylation (alkylation) using DMC and related organic carbonates.

Glycerol Carbonate as an Emulsifier for Light Crude Oil: Synthesis, Characterization, and Stability Analysis

This study focuses on the synthesis and application of glycerol carbonate (GC) as an emulsifier for light crude oil. GC was synthesized from glycerol and dimethyl carbonate via transesterification, achieving a 90% yield. Characterization through 1H-NMR, 13C-NMR, and FT-IR confirmed its structure. The emulsification properties of GC were tested by mixing it with light crude oil and water, demonstrating effective emulsification and forming stable emulsions. Stability tests with GC concentrations of 60/40, 70/30, and 80/20 revealed that emulsions remained stable for over 24 h. A particle size analysis indicated that higher GC concentrations produced smaller droplet sizes, enhancing the emulsification efficiency. This study highlights the potential applications of GC in oil spill remediation and enhanced oil recovery, emphasizing its biodegradability and low toxicity as environmental benefits. Overall, GC is presented as an effective and eco-friendly emulsifier for light crude oil, offering stable emulsions and promising industrial applications.

Palladium-Catalyzed Cascade Distal C-H Methylation and Cyclization for the Construction of Spirooxindole Skeletons.

Transition metal-catalyzed C-H methylation represents a straightforward approach for introducing methyl groups into organic molecules. Herein, we report a palladium-catalyzed alkene-relayed remote C-H methylation reaction that utilizes dimethyl carbonate as the methylation reagent. The aryl groups distal to a bromo group were dimethylated via C-H activation, leading to the formation of spirooxindoles as the final products through C(sp3)-H activation and C(sp3)-C(sp3) coupling. This cascade process involves the formation of four C-C bonds and the activation of three C-H bonds. The reaction not only provides a new approach to C-H methylation but also offers a novel method for constructing spirooxindole skeletons by merging skeleton construction and methylation into a single step.

Unveiling Eco-Friendly Reverse Micelle Systems: Dimethyl Carbonate as a Novel Biocompatible Solvent.

In this study, we systematically explored the characteristics of dimethyl carbonate (DMC)/sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT) reverse micelles (RMs) in the presence of water using dynamic light scattering (DLS), proton nuclear magnetic resonance (1H NMR), and molecular probes. DMC, a biocompatible solvent, enables the formulation of AOT RMs without the need for a co-surfactant. DLS revealed that as the water content increased, the droplet sizes grew larger. 1H NMR studies indicated that at low water content, water molecules interacted with DMC via hydrogen bonding. This interaction promoted the penetration of DMC toward the interface, affecting the solvation of AOT's sulfonate group. At higher water content, a competition for hydrogen bonding emerged between water-water and water-surfactant molecules, leading to distinct interfacial properties, as evidenced by molecular probes. The critical micellar concentration for DMC/AOT/water RMs was 7x10-3 M, similar to RMs formed with other biocompatible solvents. The presence of water facilitated the solvation of the surfactant's polar regions, promoting the RMs formation. The polarity of this system was measured using the ET(30) value. This novel micellar system holds significant potential in various fields, including catalysis, nanomaterials, and green chemistry.

Ruthenium(II)-Catalyzed C–H Allylation of N,N-Dialkylthiobenzamides with Allyl Methyl Carbonate by Sulfur Coordination

AbstractThis report describes a Ru(II)-catalyzed C–H allylation of N,N-dialkylthiobenzamides with allyl methyl carbonate. The reaction is carried out using [RuCl2(p-cymene)]2 in the presence of Cu(OAc)2 and Ag2O. This method represents the first example of a Ru-catalyzed C–H allylation directed by a sulfur-containing group. As a further advantage, the method is performed in sustainable and ecofriendly MeCN as the solvent.

Simulation and optimization of DMC synthesis process based on conventional and advanced exergy analyses

Dimethyl carbonate has received more and more attentions as an organic solvent in electrolytes. Aiming at the problem of high energy consumption in the process of dimethyl carbonate (DMC) production, the root of the problem was analyzed by using exergy analysis, which provides a theoretical basis for the construction of energy-saving process. Firstly, the overall process of DMC production was constructed, including propylene carbonate (PC) synthesis, DMC synthesis, azeotrope separation and propylene glycol (PG) purification processes. Secondly, the conventional and advanced exergy analyses of the four proposed processes were carried out. The distributions of exergy and exergy destruction were obtained through conventional exergy analysis. The exergy destructions were further divided through advanced exergy analysis, and the avoidable parts were focused on. Based on the above analyses, the corresponding heat integration processes were proposed. Finally, the conventional processes and the heat integration processes were evaluated with the performance indicators of the exergy destruction, total annual cost (TAC), total energy consumption (TEC) and CO2 emissions.

Formulating Electrolytes for 4.6 V Anode-Free Lithium Metal Batteries

High-voltage initial anode-free lithium metal batteries (AFLMBs) promise the maximized energy densities of rechargeable lithium batteries. However, the reversibility of the high-voltage cathode and lithium metal anode is unsatisfactory in sustaining their long lifespan. In this research, a concentrated electrolyte comprising dual salts of LiTFSI and LiDFOB dissolved in mixing solvents of dimethyl carbonate (DMC) and fluoroethylene carbonate (FEC) with a LiNO3 additive was formulated to address this challenge. FEC and LiNO3 regulate the anion-rich solvation structure and help form a LiF, Li3N-rich solid electrolyte interphase (SEI) with a high lithium plating/stripping Coulombic efficiency of 98.3%. LiDFOB preferentially decomposes to effectively suppress the side reaction at the high-voltage operation of the Li-rich Li1.2Mn0.54Ni0.13Co0.13O2 cathode. Moreover, the large irreversible capacity during the initial charge/discharge cycle of the cathode provides supplementary lithium sources for cycle life extension. Owing to these merits, the as-fabricated AFLMBs can operate stably for 80 cycles even at an ultrahigh voltage of 4.6 V. This study sheds new insights on the formulation of advanced electrolytes for highly reversible high-voltage cathodes and lithium metal anodes and could facilitate the practical application of AFLMBs.

Kinetic and mechanistic studies on the synthesis of dimethyl carbonate reaction using deep eutectic solvents as catalysts

Dimethyl carbonate (DMC) is extensively utilized in various industries due to its exceptional physical and chemical properties, functioning as an additive in gasoline and an electrolyte solvent in lithium batteries. Among several production methods, the transesterification of propylene carbonate (PC) with methanol (MeOH) is the most efficient and environmentally friendly. This study synthesized various deep eutectic solvents (DESs) using choline chloride (ChCl) as the hydrogen bond acceptor (HBA) and monoethanolamine (MEA) as the hydrogen bond donor (HBD) in molar ratios of 1: n (n = 5, 6, 7, 8). The DESs’ structures were analyzed using Fourier Transform Infrared (FT-IR) spectroscopy, and their melting points were determined via differential scanning calorimetry (DSC). The density, viscosity, and surface tension of the DESs were measured over a temperature range from 318.15 K to 358.15 K. The catalytic effects of four different DESs on PC transesterification with MeOH were investigated, revealing that ChCl-6MEA was the most effective catalyst, prompting its selection for further experiments. Subsequent investigations examined the effects of temperature, MeOH quantity, and catalyst dosage on PC conversion and DMC yield. Additionally, this study explored chemical equilibrium and reaction kinetics through experimental and theoretical approaches. Activity-based chemical equilibrium constants, derived from experimental data, and the van’t Hoff equation elucidated their temperature dependency. A pseudo-homogeneous (PH) model characterized the non-ideal thermodynamic behavior of the liquid phase in reaction kinetics analysis. The Arrhenius equation was employed to delineate the impact of temperature variations on reaction rate constants. Finally, the proposed reaction mechanism for ChCl-6MEA catalyzed transesterification was elucidated and verified through quantum chemistry (QC) calculations.

Multistage Linkage Internal Exclusion External Electrolyte Tactic Unlocks Extreme Fast Charge Lithium Metal Batteries.

Lithium metal batteries are booming because of their inherent preponderance, but a negative electric field from concentration dipolarization and slow solid-phase transfer at the electrode interface become blocking modules for extreme fast charging. Achieving an anion-rich solvation shell with a high dielectric constant (ε) is a feasible strategy to bootstrap an interface microenvironment for mass-transport reaction, but it is still an uncultivated field. Herein, the superposition, including the donor number values, the high ε, and the spatial potential resistance, are complementarily considered; we propose a low-cost electrolyte with an internal excluding external tactic to answer the above issue. Explanatorily, an optimized solvation shell follows the cascading exclusion relationship of nitrate ion (NO3-) → tetraglyme → ethylene carbonate → dimethyl carbonate. And the culminated bilayer structure establishes ideal conditions for Li+ transfer-reaction kinetics, of which an anion-rich internal shell facilitates solid-phase transport and a high-ε external shell slashes the negative electric field.

Development of Fluorine-Free Electrolytes for Aqueous-Processed Olivine-Type Phosphate Cathodes.

Environmental impacts and resource availability are significant concerns for the future of lithium-ion batteries. This study focuses on developing novel fluorine-free electrolytes compatible with aqueous-processed cobalt-free cathode materials. The new electrolyte contains lithium 1,1,2,3,3-pentacyanopropenide (LiPCP) salt. After screening various organic carbonates, a mixture of 30:70 wt.% ethylene carbonate and dimethyl carbonate was chosen as the solvent. The optimal salt concentration, yielding the highest conductivity of 9.6 mS·cm-1 at 20 °C, was 0.8 mol·kg-1. Vinylene carbonate was selected as a SEI-stabilizing additive, and the electrolyte demonstrated stability up to 4.4 V vs. Li+/Li. LiFePO4 and LiMn0.6Fe0.4PO4 were identified as suitable cobalt-free cathode materials. They were processed using sodium carboxymethyl cellulose as a binder and water as the solvent. Performance testing of various cathode compositions was conducted using cyclic voltammetry and galvanostatic cycling with the LiPCP-based electrolyte and a standard LiPF6-based one. The optimized cathode compositions, with an 87:10:3 ratio of active material to conductive additive to binder, showed good compatibility and performance with the new electrolyte. Aqueous-processed LiFePO4 and LiMn0.6Fe0.4PO4 achieved capacities of 160 mAh·g-1 and 70 mAh·g-1 at C/10 after 40 cycles, respectively. These findings represent the first stage of investigating LiPCP for the development of greener and more sustainable lithium-ion batteries.

Alkaline ILs Supported onto Mesoporous Polymeric 3D Spheres for Catalytic Synthesizing Dimethyl Carbonate in Transesterification

AbstractA novel type of alkyl amine‐based ILs [Et3N]+[OH]− (triethylammonium hydroxide) behaving strong alkali property have been chemically immobilized onto the polymeric 3D spheres with mesoporous structures, spherical morphology and more uniformed active species onto them to form alkali ILs supported 3D polymeric catalysts(3DPs‐ILsOH), which was synthesized via a combined method of substitution with its subsequent anion unites’ exchanging process. The supported 3DPs‐ILsOH catalyzed the transesterification of ethylene carbonate (EC) with methanol, which preferred to exhibit the excellent, efficient activities. At milder reaction temperature of 70 °C within 4.0 h, the conversion of EC achieved to 83.3 % with 99.5 % selectivity of dimethyl carbonate (DMC). Under the same reaction conditions, this type of catalysts could be recovered by a simple filtration and was reused eight times without obvious losing catalytic activities and hardly without any leaching of catalytic species. Its’ catalytic process for generating the chemical of DMC from the CO2 fixation material of EC was studied by using the in‐situ FTIR, and was further verified that the synergetic function roles of triethyl amino cations units with OH− anion units onto the supported catalysts might be one of the important reasons for progressing DMC's yields and its’ catalytic efficiency in transesterification reaction.

Exploring Electrolyte Adsorption on the Different Types of Layered Cathode Surfaces in Lithium-Ion Batteries via a Universal Neural Network Potential Method.

LiNi x Mn y Co z O2 (NCM) is a promising cathode material for lithium-ion batteries. Their long-term stability and impedance growth as cycles are strongly influenced by the properties of the cathode electrolyte interface (CEI), formed by the reaction between the electrolyte and electrode surface. Understanding of these interactions at the atomic level of the NCM electrode surface and electrolyte will provide a new strategic approach for the design of a highly functional CEI layer. In this study, we explored the influence of Ni content in transition metal layers on surface energies under different synthetic conditions and terminations using a density functional theory (DFT) validated universal neural network potential (UNNP) method. Furthermore, we investigated the adsorption of ethylene carbonate (EC) and dimethyl carbonate (DMC) on the most favorable NCM surfaces. EC and DMC displayed similar adsorption energy trends; however, differences were observed in the preferred configurations, which can affect the formation of the CEI.

Process development and environmental impact assessment of sustainable poly(3-hydroxybutyrate) separation and purification via Paraburkholderia sacchari cell lysis using crude enzymes

Downstream separation and purification of poly(3-hydroxybutyrate) has been developed via combined crude enzyme bacterial cell lysis followed by solvent extraction and circular utilisation of bacterial lysate as nutrient supplement for PHB production. Enzymatic lysis of Paraburkholderia sacchari cells was initially evaluated using crude enzymes produced via solid state fermentation of Aspergillus oryzae. The optimum protease activity (156 U per g cell dry weight) resulted in 66.9% lysis of residual cell weight. PHB purification with 1,3-dioxolane, dimethyl carbonate, anisole, ammonium laurate and chloroform were evaluated at different processing parameters (extraction duration, temperature) using wet and dry bacterial cells as well as enzymatically lysed wet bacterial cells. The highest recovery yield (94.5%) and purity (98.1%) were obtained with 1,3-dioxolane at 80°C and 6h processing time using enzymatically disrupted bacterial cells. The bacterial cell lysate was used as nutrient supplement for circular PHB production in fed-batch P. sacchari bioreactor cultures leading to the production of 78.7 gPHB/L, 56.9% (w/w) PHB content and 2.3g/(Lꞏh) productivity. Low global warming potential (1.3 CO2-eq/kgPHB) and abiotic depletion fossil (14.4 MJ/kgPHB) were estimated for PHB purification via enzymatic cell lysis and PHB extraction with 1,3-dioxolane demonstrating the development of a sustainable and circular process for PHB production.