Ethylene Carbonate Research Articles

Selective synthesis of methyl ethyl carbonate intensified by reactive distillation from consecutive transesterification of methyl carbonate and ethanol

Reactive distillation (RD) can be effectively used to improve the selectivity of the intermediate product for complex multi-reaction schemes, which involves using distillation to manipulate the column profiles in the RD column (RDC) to attribute the desired reaction and the manipulating reactions to facilitate separation. As the demand for ethyl methyl carbonate (EMC) has increased significantly due to its structural characteristics, the selective synthesis of EMC from the consecutive transesterification of dimethyl carbonate (DMC) and ethanol (EtOH) in the presence of azeotropes between reactants and products was studied as featured reaction schemes. The basic resin catalyst KC161 is utilized to build the kinetic reaction model and supplement the primary data for the process design. The pilot-scale RD experiments are explored to verify the feasibility and the reliability of the model. The impact of critical operation and structure parameters on the conversion and selectivity of the reaction and the azeotropes formed in the system were analyzed. A hybrid distillation process containing an RDC, pressure-swing distillation columns, and a regular distillation column, was designed and optimized based on minimized total annual cost (TAC) using a sequential iterative algorithm. 0. 9997 (mole purity) EMC and 0. 9999 (mole purity) diethyl carbonate (DEC) were obtained with EMC selectivity up to 0.863%.

Enhanced charge capacity and stability of Germanium(IV) Sulfide-Based anodes through Triton X100-Assisted synthesis and polysulfide shuttle mitigation

Highly soluble germanium oxide,an amorphous macroreticular form of germanium oxide, was used as a precursor for the deposition of GeS2on reduced graphene oxide (rGO) through a low-temperature, wet-chemistry process. Thermal treatment of the solid provided an ultrathin rGO – supported amorphous GeS2coating. The GeS2@rGO composite was tested as a lithium ion battery (LIB) anode. Leveraging the versatility of wet chemistry processing, we employed strategies initially developed for mitigating polysulfide shuttle effects in lithium-sulfur batteries to enhance anode performance. The anode exhibited exceptional stability, surpassing 1000 cycles, with charge capacities exceeding 1220 and 870 mAh.g−1 at rates of 2 and 5 A.g−1, respectively. Performance improvements were achieved by minimizing GeS2 grain size using the non-ionic surfactant Triton X-100 during synthesis and preventing polysulfide shuttle effects through a negatively charged thick glass fiber separator, fluoroethylene carbonate additive (FEC) in EC:DEC (ethylene carbonate: diethyl carbonate) solvent, and a polyacrylic acid (PAA) binder. These cumulative modifications more than tripled the charge capacity of the germanium sulfide LIB anode. Feasibility was further demonstrated through full cell studies using a LiCoO2 counter electrode.

Heteropoly acid catalysis in the valorization of bio-renewables: Acetylation of 1,4-cineole and 1,8-cineole (eucalyptol) in green solvents

In this work, a novel synthesis of monoterpenic acetate esters potentially valuable as flavoring agents was developed. It involves the reactions of 1,4-cineole and 1,8-cineole with acetic anhydride giving the desired products in 80–88 % total yields. The process is performed under ambient conditions in green solvents such as methyl isobutyl ketone, methyl ethyl ketone, dimethyl carbonate or diethyl carbonate in the presence of acidic cesium salt of phosphotungstic acid, Cs2.5H0.5PW12O40, as an efficient solid acid catalyst. The catalyst is stable toward leaching in the reaction system and can be reused. The process produces mixtures of acetate esters with different flavor bouquets which can be used directly as ingredients in fragrance compositions without separating individual compounds.

Effect of Temperature and Alkali Solution to Activate Diethyl Carbonate for Improving Rheological Properties of Modified Hydroxyethyl Methyl Cellulose.

The applications of cellulose ethers in the petroleum industry represent various limitations in maintaining their rheological properties with an increase in both concentration and temperature. This paper proposed a new method to improve the rheological properties of hydroxyethyl methyl cellulose (HEMC) by incorporating diethyl carbonate (DEC) as a transesterification agent and alkali base solutions. Fourier transform infrared (FTIR) analysis confirmed the grafting of both composites onto the HEMC surface. The addition of sodium hydroxide (NaOH) improved the stability of the polymeric solution as observed from ζ-potential measurement. Shear viscosity and frequency sweep experiments were conducted at concentrations of 0.25-1 wt % at ambient and elevated temperatures ranging from 80-110 °C using a rheometer. In the results, the increase in viscosity at specific times and temperatures indicated the activation of DEC through the saponification reactions with alkali solutions. All polymeric solutions exhibited shear-thinning behavior and were fitted well by the Cross model. NaOH-based modified solution exhibited low shear viscosity compared to the DEC-HEMC solution at ambient temperature. However, at 110 °C, its viscosity exceeded that of the DEC-HEMC solution due to the activation of DEC. In frequency sweep analysis, the loss modulus (G″) was greater than the storage modulus (G') at lower frequencies and vice versa at higher frequencies. This signifies the viscoelastic behavior of modified solutions at 0.50 wt % and higher concentrations. The flow point (G' = G″) shifted to a low frequency, indicating the increasing dominance of elastic behavior with the rising temperature. At 110 °C, the NaOH-based modified solution exhibited both viscous and elastic behavior, confirming the solution's thermal stability and flowability. In conclusion, modified HEMC solution was found to be effective in controlling viscosity under ambient conditions, enhancing solubility, and improving thermal stability. This modified composite could play a significant role in optimizing viscoelastic properties and fluid performance under challenging wellbore conditions.

Anion Intercalation into Graphite Electrode from Ethylene Carbonate Solutions Dissolving both Lithium Hexafluorophosphate and Lithium Bis(trifluoromethanesulfonyl)imide

Anion Intercalation into Graphite Electrode from Ethylene Carbonate Solutions Dissolving both Lithium Hexafluorophosphate and Lithium Bis(trifluoromethanesulfonyl)imide

Composition Analysis of the Solid Electrolyte Interface of NaK Anodes in Na-Ion Batteries.

Sodium-ion batteries have emerged as a promising alternative to Li-ion batteries due to the abundance of sodium. However, anodes in Na-ion batteries face challenges such as dendrite formation and an unstable solid electrolyte interface layer. To address these challenges, NaK liquid metal alloy anodes have been proposed as an alternative because they do not form dendrites. In our study, we demonstrate that the NaK alloy anode interacts with the commonly used ethylene carbonate and dimethyl carbonate electrolyte, leading to a continuously growing unstable SEI layer, evidenced by cycling failures under 100 cycles and an increasing charge transfer resistance in electrochemical impedance spectroscopy studies. In situ surface-enhanced Raman spectroscopy and X-ray photoelectron spectroscopy reveal that over the course of cycling the surface of the NaK anode becomes increasingly sodium-rich. After 30 cycles, XPS analysis detects only trace amounts of potassium on the NaK anode surface. When the electrolyte is analyzed postcycling using inductively coupled plasma optical emission spectroscopy, there is a noticeable increase in potassium levels, suggesting that potassium metal dissolves into the electrolyte. The introduction of a 10 wt % fluoroethylene carbonate additive can mitigate this problem to some extent, enabling an enhanced cycling performance of up to 800 cycles at 1C. Nevertheless, the dissolution of K metal is still evident in the XPS results, albeit to a lesser degree. These discoveries provide valuable insights for designing a more robust SEI layer for the NaK anode.

Biphasic solvents based on dual-functionalized ionic liquid for enhanced post-combustion CO2 capture and corrosion inhibition during the absorption process

To reduce the energy consumption for solvent regeneration and mitigate the corrosiveness of saturated solvents, dual-functionalized ionic liquid (IL) [DMAPA][TZ] was synthesized as a primary absorbent, and mixed with a phase separation accelerator poly (ethylene glycol) dimethyl ether (NHD) or propylene carbonate (PC) as biphasic solvents, to achieve high efficiency, energy savings, and corrosion inhibition of post-combustion CO2 capture. The results demonstrated a transition from a homogeneous solvent to a biphasic system upon CO2 absorption, with the majority of CO2 being concentrated in the rich phase, which is related to the formation of hydrogen bonds. Molecular dynamics analysis showed that interaction between the IL and PC is significantly stronger than that with NHD, resulting in a reduced absorption capacity of IL-PC relative to IL-NHD, while NHD effectively suppressed the formation of HCO3−/CO32−. At 373 K, both solvents exhibited efficient regeneration of their respective rich phases within 10 min. The calculated absorption enthalpies for IL-NHD and IL-PC are remarkably low at 0.662 and 0.772 GJ·t−1, respectively, and the regeneration energy consumption of IL-NHD was lower to 1.387 GJ·t−1. Notably, the phase separation accelerator exerts a significant influence on the phase-transition behavior and absorption products of biphasic solvents. Furthermore, ILs effectively inhibited corrosion through the adsorption-passivation mechanism; specifically, the corrosion rate of the CO2-rich phase in IL-NHD relative to 20# carbon steel was only 0.1896 mpy, which is only 1/865 of the rate of the saturated 5 M MEA solution.

Multifunctional Silane Additive Enhances Inorganic–Organic Compatibility with F‐rich Nature of Interphase to Support High‐Voltage LiNi0.5Mn1.5O4//graphite Pouch Cells

AbstractA novel electrolyte additive, 3, 3, 3‐trifluoropropylmethyldimethoxysilane (TFPMDS), is first proposed to modify both the cathode and the anode of lithium‐ion batteries at the same time. Charging/discharging tests demonstrate that the electrolyte with 1 wt% TFPMDS not only greatly improves the capacity retention of LiNi0.5Mn1.5O4 (LNMO)//Li cell (29.6%→90.8%) and graphite//Li cell (68.1%→98.3%), but also successfully ensures the long‐term cycle stability of LNMO//graphite pouch cell at 4.9 V. Further electrochemical measurements combining with spectroscopic characterization and theoretical calculations indicate that TFPMDS additive displays three principal functions: 1) Be preferentially oxidized to build a robust cathode electrolyte interphase (CEI) enriched in F/Si species with F‐rich nature of strong oxidation‐resistance. 2) Be able to scavenge the hazardous HF, F−, and H+ through its strong binding with these species and thus to protect LNMO at high‐voltage. 3) Be preferentially adsorbed on the graphite surface to form a “framework”, and to co‐construct an elastic solid electrolyte interphase (SEI) after the reduction of ethylene carbonate. Importantly, the Si─O group within TFPMDS is especially important for constructing a “molecular bridge” at the CEI/SEI interphase coupling the inorganic and organic species to improve its compatibility, stability, and elasticity.

Ether‐Based Electrolyte for High‐Temperature and High‐Voltage Lithium Metal Batteries

AbstractThe compatibility of lithium metal with organic solvents is the most crucial for lithium metal batteries (LMBs). Even though ether solvents show excellent compatibility toward lithium metal, the reactivity of the ether solvents at elevated temperatures and high voltages hinders their utilization in lithium metal battery systems. In this study, a high‐temperature ether electrolyte is designed comprising lithium oxalyldifluoroborate (LiODFB), diethylene glycol dibutyl ether (DGDE), 3‐methoxypropionitrile (MPN), and fluorinated ethylene carbonate (FEC), which is abbreviated as MDF electrolyte. The presence of MPN in the electrolyte changes the solvation structure, thereby facilitating increased redox reactions of ODFB− and synergizing with FEC to build a robust solid electrolyte interface (SEI), effectively inhibiting lithium dendrites growth and solvent decomposition. Consequently, the MDF electrolyte exhibits not only long cyclic stability and high coulombic efficiency in Li||Cu and Li||Li cells but also excellent cyclic characteristics in both Li||LiFePO4 (LFP) and Li||LiNi0.8Co0.1Mn0.1O2 (NCM811) cells. Remarkably, these cells demonstrate stable operation even when exposed to higher temperatures of up to 80 °C, while the Li||NCM811 cell maintains consistent cyclic stability at an elevated voltage level of 4.5 V.

Towards understanding the reaction network in the hydrogenation of CO2-derived ethylene carbonate

The selective hydrogenation of ethylene carbonate (EC) to produce methanol (MeOH) and ethylene glycol (EG) is a crucial route to achieve indirect and efficient utilization of CO2 under mild reaction conditions. Nonetheless, due to the cyclic carbonate structure of EC, the intricate reaction network involved in the hydrogenation process has not been systematically reported yet. Here, a series of Cu/SiO2 catalysts were designed to investigate the related reaction pathways. The catalytic evaluation results, coupled with thermodynamic calculations, reveal that there are several competitive side-reactions other than EC hydrogenation to MeOH and EG, including decarboxylation, hydrolysis and decarbonylation reactions to produce CO2 and CO as byproducts. Moreover, the distribution of products is significantly influenced by evaluation conditions. Furthermore, by doping metal oxides to adjust the surface properties of Cu/SiO2 catalyst, it is found that acidic sites could promote EC hydrolysis, whereas basic sites predominantly facilitate EC decarboxylation and decarbonylation reactions. Overall, a comprehensive reaction network of EC hydrogenation is systematically proposed to provide appropriate evaluation conditions and guidance for designing new catalysts to minimize unwanted side reactions, which is of great significance to enhance the indirect utilization of CO2.

Hypoeutectic Liquid-Solid Phase Diagrams for Ternary Lithium-Ion Battery Electrolytes.

One of the current efforts of Li-ion battery technology research is to enable the operation of lithium-ion batteries in low temperature environments (<0 °C). However, the ternary phase diagrams of liquid electrolytes commonly used in lithium-ion cells are generally unknown. We herein study the liquidus surface of a ternary liquid electrolyte─up to 1 m LiPF6 in ethylene carbonate and ethyl methyl carbonate. We find that literature electrochemical and thermodynamic measurements of the composing binary electrolytes, in addition to limited ternary liquidus data, can be used to recover the liquidus surface via appropriate mixing terms.

A Critical Analysis of Chemical and Electrochemical Oxidation Mechanisms in Li-Ion Batteries.

Electrolyte decomposition limits the lifetime of commercial lithium-ion batteries (LIBs) and slows the adoption of next-generation energy storage technologies. A fundamental understanding of electrolyte degradation is critical to rationally design stable and energy-dense LIBs. To date, most explanations for electrolyte decomposition at LIB positive electrodes have relied on ethylene carbonate (EC) being chemically oxidized by evolved singlet oxygen (1O2) or electrochemically oxidized. In this work, we apply density functional theory to assess the feasibility of these mechanisms. We find that electrochemical oxidation is unfavorable at any potential reached during normal LIB operation, and we predict that previously reported reactions between the EC and 1O2 are kinetically limited at room temperature. Our calculations suggest an alternative mechanism in which EC reacts with superoxide (O2-) and/or peroxide (O22-) anions. This work provides a new perspective on LIB electrolyte decomposition and motivates further studies to understand the reactivity at positive electrodes.

Non-flammable electrolyte for large-scale Ni-rich Li-ion batteries: Reducing thermal runaway risks

We present a novel, non-flammable electrolyte for Ni-rich 18650 cylindrical lithium-ion batteries (LIBs) based on a blend of triethyl phosphate (TEP) and fluorinated ethylene carbonate (FEC). We conducted a comprehensive analysis of the electrolyte, including electrochemical tests, safety evaluations, electrode surface characterizations, and quantum calculations, to elucidate its property-function relationship. We found that combining TEP with a concentrated FEC as a co-solvent (1.2 M LiPF6 in TEP/FEC, 30/70 %v) resulted in a robust solid electrolyte interface (SEI) predominantly composed of lithium fluoride (LiF). This innovation improved the SEI's stability and suppressed electrolyte decomposition during extended cycling, leading to consistent battery performance. Our findings introduce a promising non-flammable electrolyte solution for LIBs that offers both thermal runaway prevention and seamless integration into existing battery manufacturing processes. This positions it as a potential alternative to solid-state electrolytes in advanced battery technology, with the potential to revolutionize the field.

Readily available, biocompatible sodium citrate catalyst for efficient glycerol carbonate production through transesterification of glycerol and ethylene carbonate

As a by-product in the biodiesel industry, surplus glycerol (Gly) has attracted considerable concern. The transesterification of Gly is one of the most promising reaction pathways to convert Gly to a value-added chemical such as glycerol carbonate (GC). Currently, development of catalysts for the transesterification with high activity is underway. Herein, a readily available biocompatible sodium citrate (Na3-citrate) catalyst was applied for efficient production of GC through transesterification of Gly and ethylene carbonate (EC). The effects of reaction parameters such as reaction time, EC to Gly molar ratio, reaction temperature, and catalyst loading on the reaction were investigated. Under optimal conditions, 0.01 wt% of Na3-citrate showed high catalytic activities with a Gly conversion of > 99 %, a GC yield of > 99 %, and a high turnover frequency of 16,925 gGC⋅g−1Cat⋅h−1. Furthermore, the reaction kinetic model for transesterification was established, and the activation energy of the Na3-citrate catalyzed transesterification was calculated as 51.3 kJ·mol−1. In addition, density functional theory calculations were used to unveil mechanism of the Na3-citrate catalyzed transesterification. It revealed that citrate anion of Na3-citrate could activate hydroxy of Gly via strong hydrogen bond interaction, thereby efficiently promoting transesterification by reducing energy barrier of rate-determining step.

Polycarbonate ethanolysis with imidazolium-based ionic liquids: Recovery of high-purity BPA and value-added by-product

Depolymerization using ionic liquids (ILs) is an efficient and eco-friendly method for recycling waste poly(bisphenol A carbonate) (PC). To use IL for PC ethanolysis, the effect of IL structure on PC depolymerization should be investigated. In this study, we investigated PC ethanolysis using imidazolium-based ILs with different alkyl chain lengths (ethyl, butyl, and hexyl groups) as both the catalyst and solvent to afford the monomer bisphenol-A and a value-added byproduct, diethyl carbonate. 1-Ethyl-3-methyl imidazolium acetate ([EMIM][Ac]) exhibited the highest depolymerization efficiency, and an additional wash step increased the purity of the recovered BPA. A 100 % PC conversion rate, 90.9 % BPA yield, 99.9 % BPA purity, and 99 % [EMIM][Ac] reusability over five depolymerization cycles were observed in the PC ethanolysis using [EMIM][Ac]. In addition, recovered BPA behaved identically to commercially available BPA in the polymerization of PC. This strategy could help reduce the worldwide production of new BPA for PC synthesis.

Molecular dynamics modelling of the structural, dynamic, and dielectric properties of the {LiF - ethylene carbonate} energy storage system at various temperatures

Lithium-ion batteries (LIBs) play a vital role in advancing the hybrid industry, especially in electric vehicles, as clean and sustainable electrochemical energy sources. However, the prevalent use of organic solvents in the liquid electrolytes of these energy storage systems raises environmental concerns. In this study, we investigated the impact of a polar aprotic solvent, Ethylene Carbonate (EC), on the structural, dynamic, and dielectric properties of the LiF electrolyte using molecular dynamics simulations. By employing the CHARMM 36 force field, our goal was to comprehend the various physicochemical phenomena occurring in this electrolytic system across different temperatures within the saturation region. The structural properties were analyzed through the computation of the radial distribution function (RDF) for various pairs, while the dynamic and dielectric behaviors were elucidated by simulating the self-diffusion coefficient (D) and the dielectric constant (?).

Turning lignin into a recyclable bioresource: transesterification vitrimers from lignins modified with ethylene carbonate

Transesterification-based vitrimers from lignins modified with ethylene carbonate, to turn lignins into a recyclable aromatic bioresource.

Comparative study of the reductive decomposition reaction of ethylene carbonate in lithium battery electrolyte: a ReaxFF molecular dynamics study.

Electrolyte decomposition and subsequent solid electrolyte interphase (SEI) are considered to be the primary cause of degradation of lithium batteries. We investigate the multiple factors that can affect the reductive decomposition pathways of ethylene carbonate (EC) and SEI formation using reactive molecular dynamics. Our simulations reveal the effects of lithium concentration, simulation temperature, and the imposition of external electric field on the decomposition reaction and pathways, respectively. The comparative results reveal the increasing lithium concentration has a strong influence on EC decomposition and its pathway at each temperature. Also, the increasing temperature and imposition of an external electric field have been found to non-electrochemically and electrochemically modify the decomposition pathways of EC. This study provides insights into not only the SEI chemistry in Li-ion batteries but also that in lithium metal batteries, which can potentially contribute to the design and optimisation of future novel battery materials and electrolyte solutions.

Efficient iron-catalyzed direct acylation of amines with carboxylic acids and esters under oxygenated conditions

A new use for dioxygen at atmospheric pressure as an inducer of a highly efficient iron-catalyzed direct amidation between amines and carboxylic acids or esters in a biodegradable greener solvent such as diethyl carbonate has been discovered.

Effective synthesis of diethyl carbonate over Mg–Y composite oxides via alcoholysis of ethyl carbamate

Effective synthesis of diethyl carbonate from ethyl carbamate and ethanol using Mg–Y composite oxides.