Mixture Dimethyl Carbonate Research Articles

Vapor–Liquid Equilibrium Data for Binary Mixtures of Dimethyl Carbonate with Methyl Acetate, Ethyl Acetate, n-Propyl Acetate, Isopropyl Acetate, n-Butyl Acetate, and Isoamyl Acetate at 93.13 kPa

Isobaric vapor–liquid equilibrium (VLE) data was measured at the local atmospheric pressure of 93.13 kPa for the binary systems of dimethyl carbonate (DMC) with methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, and isoamyl acetate using a dynamic recirculation still. VLE data was generated in the form of T–x,y and was checked for thermodynamic consistency using the Herington area test, Van Ness test, and mean absolute deviation between experimental and calculated total pressure and vapor phase composition. Data for all pairs meet the criteria for thermodynamic consistency and were found suitable for process modeling. Binary interaction parameters for the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models were determined using the objective function of minimizing the deviation between the experimental and the calculated vapor phase composition and total pressure. For all binary systems, Wilson, NRTL, and UNIQUAC models g...

Diffusion coefficient of 10-methylphenothiazine and dimethyl carbonate mixture from 288.15 K to 313.15 K

Diffusivity of redox shuttle additive in solvent plays an important role in the design of Li-ion battery. As redox shuttle additive, 10-methylphenothiazine (MPT) can give good overcharge protection in LiFePO4-based Li-ion cells, therefore diffusion coefficient of MPT in solvent needs to be known. A different data processing method based on optical digital interferometry is put forward to determine diffusion coefficient in this work. This method is verified by KCl aqueous solution and the relative standard uncertainty of diffusion coefficient is about 2.3%. The diffusion coefficients of MPT in dimethyl carbonate (DMC) from 288.15K to 313.15K at several concentrations are measured and the corresponding calculation equation of diffusion coefficient is presented.

Orientational effects in mixtures of organic carbonates with alkanes or 1-alkanols

Interactions and structure of organic carbonate + alkane, and 1-alkanol + organic carbonate mixtures have been investigated by means of a set of molar excess functions, enthalpies (HmE), volumes (VmE), isobaric heat capacities, (CpmE) or entropies; and considering internal pressure (Pint); liquid-liquid equilibria or permittivity data. In addition, the mentioned systems have been studied using the Flory model and the concentration-concentration structure factorSCC(0), formalism. The mixtures under consideration are characterized by dipolar interactions and by homocoordination (that is, by interactions between like molecules). In systems with a given solvent, dipolar interactions are weakened in the order: propylene carbonate (PC) > dimethyl carbonate (DMC) > diethyl carbonate (DEC). Comparison of mixtures containing DMC or DEC with those involving 2-propanone or 3-pentanone shows that dipolar interactions are not determined merely by values of the dipole moment, but they also depend on the size group. The enthalpies of the alkanol-carbonate interactions have been evaluated from calorimetric data. They are stronger in DMC solutions, and become weaker when the alcohol size increases in mixtures with a given carbonate. Application of the Flory model to 43 systems of the type 1-alkanol + carbonate provides a mean relative standard deviation for HmE equal to 0.107. Results reveal that orientational effects decrease in the order DEC > PC > DMC. Orientational effects are particularly relevant in methanol or ethanol + DEC mixtures. Interestingly, the mentioned effects are weaker in 1-alkanol + DMC mixtures than in DMC + alkane systems. A similar trend is observed in DEC solutions when the considered alcohol is longer than ethanol.

Steric and electronic effects to interpret non-covalent interactions in binary mixtures of dimethyl carbonate and isomeric cresols through thermophysical, acoustic and spectroscopic studies

The densities (ρ), viscosities (η) and ultrasonic velocities (u) were measured for the binary mixtures of dimethyl carbonate (DMC) and isomeric cresols viz., o-cresol, m-cresol, p-cresol over the entire range of composition at atmospheric pressure and at different temperatures (303.15, 308.15,313.15, 318.15) K. From these experimental results, excess molar volume $$(V_{\text{m}}^{\text{E}} )$$ , deviation in adiabatic compressibility (Δβ ad), excess intermolecular free length ( $$L_{\text{f}}^{\text{E}}$$ ), excess acoustic Impedance (Z E), deviation in viscosity (Δη), excess Gibbs free energy of activation of viscous flow $$\left( {\Delta G^{{*{\text{E}}}} } \right)$$ and excess enthalpy ( $$H^{\text{E}}$$ ) have been calculated. The excess or deviation properties were fitted to Redlich–Kister polynomial equation to obtain their coefficients and standard deviations. The excess or deviation properties were found to be either negative or positive depending on the molecular interactions between the components of hetero molecules, and the nature of liquid mixtures has been discussed in terms of molecular interactions through steric and electronic effects. To know more about solute–solvent interactions, partial molar volumes ( $$\bar{V}_{{{\text{m}},1}} ,\bar{V}_{{{\text{m}},2}}$$ ) and excess partial molar volumes ( $$\bar{V}_{{{\text{m}},1}}^{\text{E}} , \bar{V}_{{{\text{m}},2}}^{\text{E}}$$ ) have been computed. Further, variation of excess molar enthalpy with pressure is also evaluated to elucidate the molecular interactions in the liquid mixture. The present investigation also comprises of evaluation of the acoustic nonlinearity parameter (B/A) in the mixtures and calculation of cohesive energy (ΔA), Van der Wall’s constants (a, b), distance of closest approach (d). The FTIR provides support to the thermodynamic findings to explain specific interaction between unlike molecules.

Viscometric Study of Molecular Interactions in Dimethyl Carbonate +n-Alkoxyethanol Mixtures at Different Temperatures

The viscosities (η) and densities (ρ) have been measured for the binary mixtures of dimethyl carbonate (DMC) with 2-alkoxyethanols such as 2-methoxyethanol (MOE), 2-ethoxyethanols (EOE) and 2-butoxyethanols (BOE) over the entire range of mole fraction at T=(303.15, 308.15, 313.15, 318.15) K and at constant atmospheric pressure. The excess/deviation properties such as deviation in viscosity and excess Gibbs free energy of activation of viscous flow are calculated. Excess/deviation properties are correlated by the Redlich-Kister equation to obtain the binary coefficients and standard deviations. Further several semi empirical models such as Grunberg-Nissan, Katti- Chaudhri, Heric-Brewer and Hind et al. are used to correlate the viscosity of binary mixtures. The values of Δη, which refers to the deviation of the experimental values of the viscosity of the mixture from the mole fraction mixture law rules, are found to be negative for all the mixtures. The results are discussed in terms of molecular interactions due to physical, chemical and structural effects between the unlike molecules.

Separation of an azeotropic mixture of dimethyl carbonate and methanol via partial heat integration pressure swing distillation

AbstractA method for dimethyl carbonate and methanol separation using pressure swing distillation is presented, and the optimum design is proposed by minimizing the total annual cost as the objective function. It is revealed that compared with no heat integration pressure swing distillation (HIPSD), partial HIPSD reduces the total annual cost by 20.01%. This paper presents a criterion for selection of the temperature control stage in the low‐pressure column (LPC), the temperature profile of which is quite close to linear. Additionally, the influences of the temperature stage in the LPC on the dynamic responses in the partial HIPSD are investigated. The results show that the composition/temperature cascade control structure with stage 10 or 31 selected as the control stage in the LPC can achieve efficient controllability of the process, even for large feed flow rates and composition disturbances. © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.

Densities, Viscosities, and Refractive Indices of Dimethyl Carbonate + 1-Hexanol/1-Octanol Binary Mixtures at Different Temperatures

The densities, viscosities, and refractive indices for the binary mixtures of dimethyl carbonate (DMC) + 1-hexanol/1-octanol were measured at atmospheric pressure and temperature of 293.15, 298.15, 303.15, 308.15, 313.15, 318.15, and 323.15 K over the whole concentration range. Different thermodynamic, transport, and optical properties, such as excess molar volume, partial molar volume, thermal expansion coefficient, isothermal coefficient of pressure excess molar enthalpy, activation energy of flow, excess refractive index, and electronic polarizability were obtained from the experimental data. The results were analyzed in terms of specific molecular interactions and mixing behavior between mixture components with taking into considerations the effect of temperature. Moreover, the thermophysical properties were examined with predictive and correlative equations. The quality of the predictions for the studied systems was evaluated by measuring the deviations and drawing the comparison plots.

ChemInform Abstract: Oxidation of Aryl Sulfides to Sulfones with Alumina‐Supported Ruthenium Catalyst in Dimethyl Carbonate—Water Media.

A new procedure for the oxidation of sulfides to sulfones utilizing heterogeneous ruthenium reagent has been developed. A small amount of ruthenium trichloride (RuCl 3 ) supported on alumina and excess sodium metaperiodate (NaIO 4 ) was used to produce the ruthenium oxidizing catalyst in the reaction mixture. Sodium metaperiodate oxidized the pre-catalyst RuCl 3 to RuO 4 and also maintained a constant supply of RuO 4 by oxidizing lower valent ruthenium ions during the course of the reaction. An environmentally friendly solvent mixture of dimethyl carbonate (DMC) and water was employed. A wide variety of aromatic sulfides were oxidized to sulfones in good to excellent yields by utilizing this procedure.

Chopping high‐molecular weight poly(1,4‐butylene carbonate‐co‐aromatic ester)s for macropolyol synthesis

ABSTRACTThe condensation of a mixture of dimethyl carbonate and phthalate derivatives with 1,4‐butanediol (BD), catalyzed by sodium alkoxide, generated high‐molecular weight poly(1,4‐butylene carbonate‐co‐aromatic ester)s with molecular weights (Mn) of 50–120 kDa. The subsequent addition of polyols [BD, glycerol propoxylate, 1,1,1‐tris(hydroxymethyl)ethane, or pentaerythritol] chopped these high‐molecular weight polymers to afford macrodiols or macropolyols with facile control of their molecular weights (Mn, 2000–3000 Da) and unique chain topological compositions. Macropolyols prepared by chopping poly(1,4‐butylene carbonate‐co‐terephthalate) were waxy in nature, whereas those containing isophthalate and phthalate units were oily. The macropolyols synthesized by this chopping method may have potential applications in the polyurethane industry. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43754.

Investigation into glutaraldehyde crosslinked chitosan/cardo-poly-etherketone composite membrane for pervaporation separation of methanol and dimethyl carbonate mixtures

Methanol/dimethyl carbonate mixtures were separated using GA–STA–CS/PEK-C membrane, which was prepared using glutaraldehyde (GA) crosslinked silicatungtic acid hydrate (STA)/chitosan (CS) as active layer and cardo-polyetherketone (PEK-C) as substrate.

Oxidation of Aryl Sulfides to Sulfones with Alumina-Supported Ruthenium Catalyst in Dimethyl Carbonate–Water Media

A new procedure for the oxidation of sulfides to sulfones utilizing heterogeneous ruthenium reagent has been developed. A small amount of ruthenium trichloride (RuCl 3 ) supported on alumina and excess sodium metaperiodate (NaIO 4 ) was used to produce the ruthenium oxidizing catalyst in the reaction mixture. Sodium metaperiodate oxidized the pre-catalyst RuCl 3 to RuO 4 and also maintained a constant supply of RuO 4 by oxidizing lower valent ruthenium ions during the course of the reaction. An environmentally friendly solvent mixture of dimethyl carbonate (DMC) and water was employed. A wide variety of aromatic sulfides were oxidized to sulfones in good to excellent yields by utilizing this procedure.

Ab Initio Characterization of the Electrochemical Stability and Solvation Properties of Condensed-Phase Ethylene Carbonate and Dimethyl Carbonate Mixtures

A central challenge in the refinement of lithium-ion batteries is to control cathode-induced oxidative decomposition of electrolyte solvents, such as ethylene carbonate (EC) and dimethyl carbonate (DMC). We study the oxidation potentials of neat EC, neat DMC, and 1:1 mixtures of EC and DMC using the newly developed projection-based embedding method, which we demonstrate to be capable of correcting qualitative inaccuracies in the electronic densities and ionization energies obtained from conventional Kohn–Sham density functional theory (DFT) methods. Our wave function-in-DFT embedding approach enables accurate calculation of the vertical ionization energy (IE) of individual molecules at the CCSD(T) level of theory while explicitly accounting for the solvent using a combination of DFT and molecular mechanics interactions. We find that the ensemble-averaged distributions of vertical IEs are consistent with a linear response interpretation of the statistics of the solvent configurations, enabling determination of both the intrinsic oxidation potential of the solvents and the corresponding solvent reorganization energies. Interestingly, we reveal that large contributions to the solvation properties of DMC originate from quadrupolar interactions, resulting in a much larger solvent reorganization energy than that predicted using simple dielectric continuum models. Demonstration that the solvation properties of EC and DMC are governed by fundamentally different intermolecular interactions provides insight into key aspects of lithium-ion batteries, with relevance to electrolyte decomposition processes, solid–electrolyte interphase formation, and the local solvation environment of lithium cations.

The Stability of Carbonaceous Electrodes in Ether Based Electrolyte Solutions for Advanced Li Batteries

In this work we have studied the stability and performance of hard carbon in comparison with petroleum coke (soft carbon) as electrode materials for Li-ion batteries in an ethereal and alkyl carbonate based electrolyte solutions. 1 M bis(triflouromethane) sulfonimide lithium salt (LiTFSI) in diethylene glycol dimethyl ether (diglyme)) and a mixture of dimethyl carbonate (DMC)/mono-fluorinated ethylene carbonates (FEC) 4:1 (%v) with 1 M Lithium hexaflourophosphate (LiPF6) where chosen as representative solutions for this study. The motivation for this work is the potential importance of ethereal solutions for high energy density Li-S and Li-O2 batteries and the possibility of using carbons as an alternative to Li metal anodes in these systems. An acceptable performance of hard carbon electrodes in the ether based solutions was demonstrated. In contrast, soft carbon electrodes which preform very well in alkyl carbonates solutions behave poorly in the ethereal solutions. Their failure mechanism was explored and is explained in this report.

Characterization of LTO//NMC Batteries Containing Ionic Liquid or Carbonate Electrolytes after Cycling and Overcharge

Electrochemical stabilities under cycling and overcharge of Li4Ti5O12 (LTO) // LiNi1/3Mn1/3Co1/3O2 (NMC) batteries with two ionic liquid-based electrolytes and a commercial electrolyte were investigated at 25 and 60°C. The electrolytes were constituted of ethylene carbonate / dimethyl carbonate mixtures with LiPF6, and of imidazolium and pyrrolidinium-based ionic liquids containing the bis(trifluoromethanesulfonyl)imide anion (NTf2) associated to LiNTf2 salt. The experiments were performed in coin and pouch cells in order to follow the evolution of the stability of both solid, liquid and gas phases. The decomposition products and stability of the electrolytes was assessed by gas chromatography coupled with infrared spectroscopy. The characterization of the electrode surfaces by SEM, XRD and XPS techniques was reported, after cycling and overcharge. The XPS analysis of both electrodes indicated that their surfaces were covered by an IL film in the case of NMC, and by several NTf2 anion decomposition products in the case of LTO. This work highlights the difference between thermal and electrochemical stability, especially for imidazolium-based electrolytes.

Supercritical carbon dioxide extraction of lithium-ion battery electrolytes

Two different separator materials (polyethylene fleece – Freudenberg 2190 and porous glass fiber – Whatman® GF/D) and two different lithium-ion battery electrolytes have been investigated regarding their behavior in an autoclave extraction with supercritical helium head pressure carbon dioxide (sc HHPCO2). Mixtures of dimethyl carbonate (DMC)/ethylene carbonate (EC) and ethylmethyl carbonate (EMC)/EC, each with 1mol/L LiPF6 were used.In addition to these proof of principle experiments, the developed extraction method was further applied to real battery samples. Commercial 18650cells (after formation and aging) were opened and the jelly roll was extracted with sc HHPCO2. Extracts were analyzed with gas and ion chromatography (GC, IC). Recovery rates and extract compositions strongly depend on the material of which the electrolyte is extracted. Further structure determination of electrolyte aging products was performed with different ionization modes in GC–mass spectrometry (GC–MS) experiments. Diethyl carbonate (DEC), dimethyl-2,5-dioxahexane dicarboxylate (DMDOHC), ethylmethyl-2,5-dioxahexane dicarboxylate (EMDOHC) and diethyl-2,5-dioxahexane dicarboxylate (DEDOHC) are aging products of electrolyte degradation which were successfully extracted and identified. Their concentrations correlate with solid electrolyte interphase (SEI) growth on the negative electrode which was investigated with scanning electron microscopy (SEM).

Ternary liquid–liquid equilibria and binary excess and deviation properties at constant temperature for mixtures of dimethyl carbonate, anisole, methanol, phenol and water

This study aims to determine the phase equilibria and mixture properties for the separation of reaction intermediates generated during the synthesis of non-phosgene diphenylcarbonate (DPC). The intermediates are based on dimethyl carbonate (DMC), phenol, methanol and anisole, etc. We analytically determined ternary liquid–liquid equilibria (LLE) for the following mixtures at atmospheric pressure and constant temperature: {water+DMC+anisole} at 313.15K, {water+methanol+anisole} at 308.15K and {water+methanol+phenol} at 328.15K. In addition, density, refractive indices, excess molar volumes (VE) and deviations in the molar refractivity (ΔR) of constituent binary systems at 298.15K were determined. The experimental LLE data correlated well with two excess Gibbs free energy models: Non-Random Two-Liquid (NRTL) and UNIversal QUAsiChemical (UNIQUAC). VE and ΔR data were correlated well with Redlich–Kister polynomial.

Biodiesel Production by Transesterification of Corn Oil with Dimethyl Carbonate Under Heterogeneous Base Catalysis Conditions Using Potassium Hydroxide

We have studied the process of transesterification of corn oil with dimethyl carbonate (DMC) in the presence of a heterogeneous catalyst: potassium hydroxide (KOH). Response surface methodology was used to optimize the three transesterification variables: reaction time, dimethyl carbonate:oil ratio, and catalyst loading. The Box–Behnken design was used to study the influence of these variables on the yield of fatty acid methyl esters (FAMEs) and an empirical model was developed. The maximum yield of FAMEs (90.9%) with low pour point (–11°C) was achieved by boiling a mixture of dimethyl carbonate and the oil (mole ratio 9:1) and 16.3 wt.% catalyst (based on oil weight) for 9 hours. The kinetics of KOH-catalyzed transesterification of triglyceride (TG) and diglyceride (DG) with DMC was studied in the temperature range 65°C-75°C. We found that both reactions are pseudo-second order, and the activation energy for transesterification of triglycerides and diglycerides is equal respectively to 83.3 and 89.8 kJ/mol.

LiNi0.5Mn1.5O4 Thin-Film Cathodes on Gold-Coated Stainless Steel Substrates: Formation of Interlayers and Electrochemical Properties

Thin films of LiNi0.5Mn1.5O4 (LNMO) were prepared on gold-coated stainless steel substrates via a poly(vinylpyrrolidone)-based sol-gel process. Films with a thickness in the range of 1μm were found to exhibit a capacity close to the theoretical one. The formation of interlayers (i) between the LNMO films and the LP30 electrolyte (mixture of dimethyl carbonate (DMC) and ethylene carbonate (EC) (1:1 v/v) containing 1 mol·l−1LiPF6) and (ii) between the LNMO films and the gold-coated substrate was studied by means of electrochemical impedance spectroscopy (EIS), time-of-flight secondary-ion mass-spectrometry (ToF-SIMS), and scanning transmission electron microscopy together with energy dispersive X-ray spectroscopy (STEM/EDX). The combination of these methods turns out to be very powerful for understanding the chemical composition and properties of interlayers and for identifying the origin of semicircles in Nyquist impedance plots. At the LNMO/LP30 interface, we observe an interlayer (solid electrolyte interface, SEI) with a thickness of about 50 nm, while at the LNMO/gold interface, a mixed oxide layer with a thickness in the range of 250nm is found. The mixed oxide layer is caused by diffusion of Cr and Ni from the stainless steel through the gold layer. While the LNMO/LP30 interlayer contributes significantly to the interfacial impedance, the impedance of the LNMO/gold interlayer seems to be negligible, despite its larger thickness.

Synthesis and characterization of a novel type of mixed matrix membrane: surface sieving membrane

A novel surface sieving membrane was prepared by attaching zeolite crystals on the polymer membrane surface. The top zeolite layer serves as a pre-screen layer which only allows the permeation of small molecules based on a molecular sieving mechanism. The separation factor of the new membrane was substantially increased by 300% for the pervaporation separation of a methanol–dimethyl carbonate mixture.

Synthesis of dimethyl carbonate and propylene glycol in a pilot-scale reactive distillation column: Experimental investigation, modeling and process analysis

The transesterification of propylene carbonate with methanol to produce the two valuable products dimethyl carbonate and propylene glycol is associated with an unfavorable chemical equilibrium and complex thermodynamic behavior. This results in a challenging and cost-intensive process currently used for their production. The application of reactive distillation, which integrates chemical reaction and distillation into one single column is considered as potential candidate to improve efficiencies and product yields within chemical-equilibrium-limited systems. However, the design of such a column for industrial-scale applications is challenging as it needs the integration of model-based approaches with reliable experimental data. This paper presents an experimental and theoretical investigation of the simultaneous production of dimethyl carbonate and propylene glycol in a pilot-scale reactive distillation column. Experiments varying decisive operating parameters were successfully performed showing the feasibility of simultaneously producing dimethyl carbonate and propylene glycol in a reactive distillation column. The experimental results were used to select and validate a modeling approach for the simulation of the reactive distillation process. The successfully validated non-equilibrium stage model was applied to perform a process analysis pointing out the trends of both the reactant conversions and the product purities. The simulation results showed the option of achieving high propylene carbonate conversions while recovering an azeotropic mixture of dimethyl carbonate and methanol in the distillate. These results define the operating range for the economic optimization and establishment of an industrial-scale reactive distillation process for this chemical system.