Mixture Of Propylene Carbonate Research Articles

Studies on Sodium Ion Conducting Gel Polymer Electrolytes

Sodium ion conducting gel polymer electrolyte (GPE) films consisting of polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP) as a polymer host were prepared using the solution casting technique. Sodium trifluoromethane-sulfonate (NaCF3SO3) was used as an ionic salt and the mixture of ethylene carbonate (EC) and propylene carbonate (PC) as the solvent plasticizer. The GPE films were found to be stable up to temperature of 145 °C as shown by TGA analysis. The AC impedance study show that the optimum conductivity of 2.50 x 10-3 S cm-1 at room temperature is achieved for the film containing 20 wt.% of NaCF3SO3 salt. The temperature dependence of conductivity obeys VTF relation in the temperature range of 303 K to 373 K.

Leakage currents and self-discharge of ionic liquid-based supercapacitors

Ionic liquid (IL)-based supercapacitors have been widely demonstrated to outperform electrochemical double-layer capacitors (EDLCs) working with conventional organic electrolytes in terms of specific energy and operating voltage. Here, the results of a study on the leakage currents (I leak) and self-discharge energy loss factors (SDLF) of IL-based EDLCs at different cell voltages up to 3.2 V and at 30° and 60 °C are reported. Cells assembled with the N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl) imide (PYR14TFSI) and N-methoxyethyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide pure ILs and a mixture of PYR14TFSI and propylene carbonate (PC) 1 to 1 molar were tested. The results are compared to those achieved with EDLCs featuring the conventional 1 M tetraethyl ammonium tetrafluoroborate (Et4NBF4)-PC electrolyte. The study demonstrates that ILs provide I leak and SDLF that are lower than those obtained with the latter electrolyte, with PYR14TFSI allowing the lowest values.

Anodic Aluminum Dissolution of LiTFSA Containing Electrolytes for Li-Ion-Batteries

In this study, novel electrolyte solvents and the conducting salt lithium bis(trifluoromethanesulfonyl)azanide (LiTFSA) are compared with respect to aluminum anodic dissolution, often called in an ambiguous manner aluminum corrosion. Namely, mixtures of propylene carbonate, sulfolane, the ionic liquid N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)azanide (DMMA-TFSA) and various concentrations of LiTFSA are prepared and investigated in Al|Li cell configuration. It is verified that the choice of the concentration of LiTFSA and the composition of the solvent mixture affects the tendency of Al dissolution significantly. Principally, the best results (least dissolution/corrosion) are obtained in case of high LiTFSA concentrations and by adding the ionic liquid DMMA-TFSA to the organic solvents.

Fluoroethylene Carbonate and Propylene Carbonate Mixtures Based Electrolytes for Supercapacitors

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Quasi solid state dye-sensitized solar cells based on polyvinyl alcohol (PVA) electrolytes containing $$\mathbf{I}^{\mathbf{-}}/\mathbf{I}_{\mathbf{3}}^{\mathbf{-}}$$ I - / I 3 - redox couple

Quasi solid state dye-sensitized solar cells (DSSCs) have been fabricated with electrolytes containing I-/I-3(-) redox couple using 80% hydrolyzed polyvinyl alcohol (PVA) doped with potassium iodide (KI) and a mixture of potassium iodide and tetrapropyl ammonium iodide (Pr4NI) salts. The quasi solid state gel polymer electrolytes were prepared using 1: 1 ethylene carbonate (EC): propylene carbonate (PC) mixture. The solar cells have the structure of ITO/TiO2/N-3-Dye/electrolyte/Pt/ITO. The conductivity of the electrolytes has been calculated from the bulk resistance value determined using the electrochemical impedance spectroscopy. The performance of the DSSCs has been studied by varying the concentration of the doping salts in the electrolyte and incident light intensity. The DSSC fabricated with the KI salt electrolyte containing 9.9 wt% PVA, 39.6 wt% EC, 39.6 wt% PC, 10.9 wt% KI(+I-2) exhibited the best power conversion efficiency of 1.97 %. However, the DSSC with a double-salt electrolyte containing 9.9 wt% PVA: 39.6 wt% EC: 39.6 wt% PC: (6.5 wt% KI: 4.4 wt% Pr4NI) (+I-2) exhibited a higher efficiency of 3.27% under 100 mW/cm(2) light intensity. The efficiency of this cell increased to 4.59 % under dimmer light of intensity of 54 mW/cm(2).

Sn–O–C composite anode for Li secondary battery synthesized by an electrodeposition technique using organic carbonate electrolyte

The Sn–O–C composite anode for the Li secondary battery was synthesized by electrodeposition using an organic carbonate solvent. The composite of Sn with organic/inorganic compounds was prepared by the simultaneous reaction of the reduction of Sn2+ ions and electrolysis of the mixture of ethylene carbonate and propylene carbonate. The galvanostatic potential transients for the electrodeposition of the Sn–O–C composite indicate that multiple steps of reactions corresponding to the electrochemical reduction of the tin precursor and the decomposition of organic solvents are involved. The morphology, crystalline structure and chemical composition of the as-deposited Sn–O–C composite anode were characterized to elucidate the mechanism of the synthesis of the buffering matrix enduring volume expansion.The electrochemical behavior of the Sn–O–C composite anode was investigated by cyclic voltammetry and galvanostatical charge/discharged tests. The discharge capacity of 465 mAh (g of Sn)−1 was obtained at the 100th cycle showing 80% of the capacity retention after the 100th cycle. The discharge capacity was stable after the 50th cycle, where the phase transformation of the Sn element from Sn to Li0.4Sn at the discharged state was found.

Structure, Disorder, and Crystallization; Lessons Learned from Analysis of Lithium Trifluoromethanesulfonate

Batteries are one of the most impactful inventions humankind has ever developed. Lithium-ion energy cells represent a significant advance in battery technology. Electrolytes used in batteries are still not well understood in terms of solution structure. We investigate electrolyte solvate structure with the aid of differential scanning calorimetry, Raman spectroscopy, and X-ray diffraction. Here is a report on the solvate structure(s) present in mixtures of propylene carbonate (PC) and lithium trifluoromethanesulfonate (LiTf). Mixtures of racemic PC with LiTf form glasses whereas enantiomerically pure PC, both R and S isomers, forms mixtures with more complex phase behavior. At concentrations approaching a 1:1 molar ratio of solvent to salt, a solvate that melts at ~150 °C was detected. A crystal of the 1:1 solvate of the R-(+)-PC:LiTf was successfully grown and analyzed by X-ray diffraction. This solvate has an aggregated structure where the Li+ cations are tetrahedrally coordinated. Three directions of coordination come from Tf– anions acting as a bridging ligand between three different Li+ cations and the 4th direction of coordination comes from the carbonyl oxygen of the solvent molecule.

Ionic Conductivity, Morphology and Transport Number of Lithium Ions in PMMA Based Gel Polymer Electrolytes

The gel polymer electrolytes (GPEs) composed of polymethylmethacrylate (PMMA) with lithium trifluoromethanesulfonate (LiCF3SO3) salt dissolved in a binary mixture of ethylene carbonate (EC) and propylene carbonate (PC) organic solvents have been prepared by the solution casting technique. The samples are prepared by varying the salt concentrations from 5 wt.% to 30 wt.%. Impedance spectroscopy measurement has been carried out to determine the ionic conductivity of the samples. The sample containing 25 wt.% of LiCF3SO3 salt exhibits the highest room temperature ionic conductivity of 2.56 x 10-3 S cm-1. The conductivity of the GPEs has been found to depend on the salt concentration added to the sample, while at higher salt concentration reveals a decrease in the ionic conductivity due to ions association. The temperature dependence of conductivity from 303 K to 373 K is found to obey the Arrhenius law. The ionic transference number, ti of GPEs has been estimated by the DC polarization method and the value is found to be 0.98, 0.93, and 0.97 for the sample containing 25 wt.%, 5 wt.% and 30 wt.% respectively. This result is consistent with the conductivity studies.

Low temperature pretreatment of sugarcane bagasse at atmospheric pressure using mixtures of ethylene carbonate and ethylene glycol

A low temperature lignocellulose pretreatment process was developed using acid-catalysed mixtures of alkylene carbonate and alkylene glycol. Pretreatment of sugarcane bagasse with mixtures of ethylene carbonate (EC) and ethylene glycol (EG) was more effective than that with mixtures of propylene carbonate (PC) and propylene glycol (PG). These mixtures were more effective than the individual components in making bagasse cellulose more amenable to cellulase digestion. Glucan digestibilities of ≥87% could be achieved with a wide range of EC to EG ratios from 9 : 1 to 1 : 1 (w/w). Pretreatment of bagasse by the EC–EG mixture with a ratio of 4 : 1 in the presence of 1.2% H2SO4 at 90 °C for 30 min led to the highest glucan enzymatic digestibility of 93%. The high glucan digestibilities obtained under these acidic conditions were due to (a) the ability of alkylene carbonate to cause significant biomass size reduction, (b) the ability of alkylene glycol to cause biomass defibrillation, (c) the ability of alkylene carbonate and alkylene glycol to remove xylan and lignin, and (d) the magnified above attributes in the mixtures of alkylene carbonate and alkylene glycol.

Specific Performance of Supercapacitors at Lower Temperatures Based on Different Separator Materials

Influence of temperature and the separator material characteristics (composition, porosity, structure) on the performance of supercapacitors (SCs), based on microporous titanium carbide−derived carbon electrodes in 1 M triethylmethylammonium tetrafluoroborate solution in dimethyl carbonate, ethylene carbonate and propylene carbonate mixture with 1:1:1 volume ratio, has been tested by cyclic voltammetry, constant power and electrochemical impedance spectroscopy methods at temperatures from +24 to −30°C. Self−made separator materials have been prepared from poly(vinylidene fluoride) solutions in N,N−dimethylacetamide or N,N−dimethylformamide and acetone mixture (8:2 mass ratio) by using the electrospinning method. Noticeable influence of temperature, porosity and chemical composition of separator on the shape of cyclic voltammetry curves and Nyquist plots, low−frequency limiting series capacitance and resistance, parallel capacitance and resistance, time constant, complex power components, and specific energy and power of the SCs has been established and discussed.

Studies of a plasticized PEO + NH4PF6 proton-conducting polymer electrolyte system and its application in a proton battery

We have synthesized polyethylene oxide (PEO) + NH4PF6 polymer electrolyte films plasticized with ethylene carbonate (EC) and a mixture of ethylene carbonate and propylene carbonate (EC/PC) by using a solution cast technique. X-ray diffraction (XRD) results show a decrease in crystallinity from ∼67% in the unplasticized complex to 39% and 35% in the EC- and the EC/PC-plasticized complexes, respectively. Scanning electron microscopy (SEM) results show the formation of a fringed miscellar structure in the plasticized complexes. An increased coordination between dissociated ions and the ether oxygen of PEO on plasticization is established from the Fourier transform infrared (FTIR) studies. The ionic conductivity shows an enhancement of about two orders of magnitude on plasticization. The room-temperature ionic conductivities of the highest conducting compositions are obtained as ∼1.52 × 10−5 S cm−1 and ∼1.03 × 10−5 S cm−1 in the EC- and the EC/PC-plasticized complexes, respectively. The highest conducting compositions of plasticized polymer electrolyte films are used to fabricate proton batteries with the configuration Zn/ZnSO4.7H2O (anode) ‖Polymer electrolyte‖ PbO2/V2O5 (cathode), and different battery parameters are reported.

Composite Carbon Nano-Tubes (CNT)/Activated Carbon Electrodes for Non-Aqueous Super Capacitors Using Organic Electrolyte Solutions

We present herein activated carbon/carbon nano tube (AC/CNT)) composite electrodes for non-aqueous, high voltage electrical double layer capacitors (EDLC). Mixtures comprising CNT and polymeric species were carbonized and further activated, thus forming matrices with unique hierarchical porous structure, with both micro- and meso-pores. The possible use of these electrodes in high energy density EDLC was studied with non-aqueous solutions based on mixtures of acetonitrile and propylene carbonate and tetra-ethyl ammonium tetra-fluoroborate as the electrolyte. The electrochemical performance of the composite electrodes in these non-aqueous electrolyte solutions is much better than that of electrodes comprising activated carbon without CNT. Capacitance higher than 170 F/g EDL at 2.5 V (118 mAh/g) could be demonstrated at a good rate capability with thick electrodes (>100 microns), during very prolonged cycling. After 10,000 cycles the capacitance fading measured was less than 7%.

An investigation about the use of mixtures of sulfonium-based ionic liquids and propylene carbonate as electrolytes for supercapacitors

This study describes the use of mixtures of the ionic liquid (IL) trimethyl-sulfonium bis[(trifluoromethyl)sulfonyl]imide (Me3STFSI) and propylene carbonate (PC) as electrolytes for carbon-based electrochemical double layer capacitors (EDLCs). Two different mixtures have been investigated. The first one contained the maximum amount of Me3STFSI (3.8 mol L−1) soluble in PC at room temperature (RT). The second one contained 1.9 mol L−1 of Me3STFSI, which is the concentration featuring the highest conductivity among all possible mixtures between PC and Me3STFSI at RT. The physicochemical properties, including conductivity, viscosity, and electrochemical and thermal stability of both mixtures, have been initially investigated. Afterward, the use of these mixtures as electrolytes for EDLCs has been considered. This study showed that by using these innovative electrolytes, it is possible to develop EDLCs with an operative voltage as high as 3.0 V. It was clearly demonstrated that the EDLC cycle life strongly depends on the concentration of Me3STFSI present in the mixture. Moreover, it was also proved that mixtures containing high concentrations of IL are able to suppress anodic oxidation of the Al current collector at high potential. When a solution with a high salt concentration is used, an EDLC with high energy, high cycle life and a broad temperature range of operation can be realized.

Greening pharmaceutical applications of liquid chromatography through using propylene carbonate–ethanol mixtures instead of acetonitrile as organic modifier in the mobile phases

Substitution of acetonitrile (ACN) as organic modifier in mobile phases for liquid chromatography by mixtures of propylene carbonate (PC) and ethanol (EtOH) may be considered a greener approach for pharmaceutical applications. Such a replacement is achievable without any major compromise in terms of elution order, chromatographic retention, efficiency and peak symmetry. This has been equally demonstrated for reverse phase (RP), ion pair formation (IP) and hydrophilic interaction liquid chromatography (HILIC) separation modes. The impact on the sensitivity induced by the replacement between these organic solvents is discussed for UV–vis and mass spectrometric detection. A comparison between Van Deemter plots obtained under elution conditions based on ACN and PC/EtOH is presented. The alternative elution modes were also compared in terms of thermodynamic parameters, such as standard enthalpy (ΔH0) and entropic contributions to the partition between the mobile and the stationary phases, for some model compounds. Van’t Hoff plots demonstrated that differences between the thermodynamic parameters are minor when shifting from ACN/water to PC/EtOH/water elution on an octadecyl chemically modified silicagel stationary phase. As long as large volume injection (LVI) of diluents non-miscible with the mobile phase is a recently developed topic having a high potential of greening the sample preparation procedures through elimination of the solvent evaporation stage, this feature was also assessed in the case of ACN replacement by PC/EtOH.

Dielectric constants of binary mixtures of propylene carbonate with dimethyl carbonate and ethylene carbonate from molecular dynamics simulation: comparison between non-polarizable and polarizable force fields

Using non-polarizable and polarizable molecular dynamics simulations, binary mixtures of propylene carbonate + dimethyl carbonate and propylene carbonate + ethylene carbonate with various compositions were investigated. The polarizable model produces more reasonable estimation of dielectric constants than the non-polarizable model; however, combining the electronic continuum model with the non-polarizable MD improves the comparison between the two models. Fair agreement was found between the results from these simulations and available experimental data. In addition, for a better understanding of the mixing behaviour, the excess dielectric constants over the entire composition were calculated. By comparison of the two mixtures in various mole fractions, distinctive mixing behaviours of propylene carbonate + dimethyl carbonate (poorly symmetric mixture) and propylene carbonate + ethylene carbonate (highly symmetric mixture) were observed.

Thermodynamic and dynamic properties in binary mixtures of propylene carbonate with dimethyl carbonate and ethylene carbonate

Molecular dynamics simulations of binary mixtures of propylene carbonate (PC)+dimethyl carbonate (DMC) and PC+ethylene carbonate (EC) with various compositions were performed to study thermodynamic and dynamic properties such as density, dielectric constant and self-diffusion coefficient. For a better understanding of the thermodynamic behavior of the mixtures, the excess molar volume and excess dielectric constant with the various mole fractions were calculated. In addition, a computational approach of the Molecular Dynamics with Electronic Continuum (MDEC) model combined with density functional theory was used to determine the dielectric constants. Fair agreement was found between the results from our simulations and available experimental data. By comparison of the two mixtures observed in various mole fractions, the thermodynamic and dynamic behaviors of PC+DMC were highly asymmetrical whereas those of PC+EC were nearly symmetrical.

A new series of cross-linked (meth)acrylate polymer electrolytes for energy storage

A series of methacrylate-crosslinked polymers were investigated as potential polymer electrolytes for energy storage application. Methacrylate ester crosslinkers (25–50mol.%) with different spacer lengths and MMA as comonomer were polymerised into thin films. Mixtures of ethylene carbonate and propylene carbonate (EC/PC) or alternatively the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM TFSI), both doped with lithium bis(trifluoromethane)sulfonimide (LiTFSI), fulfilled the role of electrolyte and porogen simultaneously. Ionic conductivity increased with increasing porogen content, Li ion concentration, and decreasing amounts of crosslinker (maximum values: 0.5mS/cm (EC/PC) and 4.5mS/cm (EMIM TFSI)). Thin films with permanent porosity were obtained for both electrolyte systems. The flexibility of the films increased with a lower concentration of crosslinker or the choice of a crosslinker with a longer spacer. The relationship between pore size, pore morphology, glass transition temperature and ionic conductivity on the other hand was complex and did not exhibit distinct trends. High thermal stability, ionic conductivity and tunable mechanical properties make these polymer thin films attractive candidates as in situ filled Li ion battery separator films either preformed or directly printed.

Isentropic Compressibility for Binary Mixtures of Propylene Carbonate with Benzene and Substituted Benzene

Ultrasonic velocities (u) for binary mixtures of propylene carbonate (PC) (1) with benzene and substituted benzenes (2) viz. benzene, ethylbenzene, o-xylene and p-xylene have been measured at 288.15-308.15 K over the entire range of composition. The experimental values of ultrasonic velocities (u) have been utilized to calculate isentropic compressibility (), intermolecular free length (), acoustic impedance (Z).

The solubility of carbon dioxide and propylene oxide in polymers derived from carbon dioxide

As a part of the optimization of a recently developed process through which polyurethanes are produced using carbon dioxide (CO2) as a raw material, the solubilities of CO2 and of propylene oxide (PO) in polyether polycarbonate polyols (PPP), an intermediary in the production of polyurethanes, were measured at pressures up to 10MPa and 1MPa, respectively, at temperatures between 363K and 413K. Experiments were performed using the synthetic-isothermal method. The influence of propylene carbonate, also present in the process, was investigated by studying the solubilities of CO2 and PO in different mixtures of PPP and propylene carbonate at 383K. Finally, the solubility of CO2 in a polyether, one of the reactants in the process, was also measured at 383K.The experimental results were modeled with the Soave–Redlich–Kwong equation of state with the Péneloux–Rauzy volume translation and Mathias–Klotz–Prausnitz mixing rules.

REPLACEMENT OF ACETONITRILE BY MIXTURES OF PROPYLENE CARBONATE AND METHANOL AS ORGANIC MODIFIER IN MOBILE PHASES FOR RPLC SEPARATION MECHANISM: APPLICATION TO THE ASSAY OF ALPRAZOLAM AND SERTRALINE IN COMBINED PHARMACEUTICAL FORMULATIONS

Acetonitrile (ACN), methanol (MeOH), and tetrahydrofuran are the most commonly used organic solvents in RP-HPLC. The present work suggests how ACN in the mobile phase has been efficiently replaced by a new solvent mixture of propylene carbonate (PC) and MeOH in the ratio 60:40 in RP-HPLC method for simultaneous estimation of Alprazolam and Sertraline. Presently, PC is used as a solvent for synthetic polymers and as an electrochemical solvent. However, through the present study, it has been proved that it can also be used as a mobile phase component in RP-HPLC. PC has numerous advantages over ACN with respect to boiling point, flashpoint, biodegradability, clinical toxicity, and so forth. Two RP-HPLC methods have been developed and validated for the simultaneous estimation of Alprazolam and Sertraline in combined dosage forms using both ACN and Solvent-X (PC:Methanol; 60:40), respectively, as a mobile phase component. The two methods are then compared. It is observed that the method developed using Solvent-X is rapid, reproducible, and precise and meets the acceptance criteria for all parameters set by International Conference on Harmonization (ICH). Hence, it is speculated that Solvent-X can be used as a mobile phase component in RP-HPLC for routine qualitative and quantitative analysis in industries.