The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Masayoshi Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Physicochemical properties and structures of room temperature ionic liquids. 2. variation of alkyl chain length in imidazolium cation
Journal of Physical Chemistry B, 2005Co-Authors: Hiroyuki Tokuda, Kunikazu Ishii, Md Abu Bin Hasan Susan, Kikuko Hayamizu, Masayoshi WatanabeAbstract:The alkyl chain length of 1-alkyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide ([Rmim][(CF(3)SO(2))(2)N], R = methyl (m), ethyl (e), butyl (b), hexyl (C(6)), and octyl (C(8))) was varied to prepare a series of room-temperature ionic liquids (RTILs), and the thermal behavior, density, viscosity, self-diffusion coefficients of the cation and anion, and ionic Conductivity were measured over a wide temperature range. The self-diffusion coefficient, viscosity, ionic Conductivity, and Molar Conductivity change with temperature following the Vogel-Fulcher-Tamman equation, and the density shows a linear decrease. The pulsed-field-gradient spin-echo NMR method reveals a higher self-diffusion coefficient for the cation compared to that for the anion over a wide temperature range, even if the cationic radius is larger than that of the anion. The summation of the cationic and anionic diffusion coefficients for the RTILs follows the order [emim][(CF(3)SO(2))(2)N] > [mmim][(CF(3)SO(2))(2)N] > [bmim][(CF(3)SO(2))(2)N] > [C(6)mim][(CF(3)SO(2))(2)N] > [C(8)mim][(CF(3)SO(2))(2)N], which greatly contrasts to the viscosity data. The ratio of Molar Conductivity obtained from impedance measurements to that calculated by the ionic diffusivity using the Nernst-Einstein equation quantifies the active ions contributing to ionic conduction in the diffusion components, in other words, ionicity of the ionic liquids. The ratio decreases with increasing number of carbon atoms in the alkyl chain. Finally, a balance between the electrostatic and induction forces has been discussed in terms of the main contribution factor in determining the physicochemical properties.
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Physicochemical properties and structures of room temperature ionic liquids. 1. Variation of anionic species
Journal of Physical Chemistry B, 2004Co-Authors: Hiroyuki Tokuda, Kunikazu Ishii, Md Abu Bin Hasan Susan, Kikuko Hayamizu, Masayoshi WatanabeAbstract:Room-temperature ionic liquids (RTILs) based on 1-butyl-3-methylimidazolium ([bmim]) with a variety of fluorinated anions were prepared, and the thermal behavior, density, viscosity, self-diffusion coefficients of the cations and anions, and ionic Conductivity were measured over a wide temperature range. The temperature dependencies of the self-diffusion coefficient, viscosity, ionic Conductivity, and Molar Conductivity have been fitted to the Vogel−Fulcher−Tamman equation, and the best-fit parameters for the self-diffusion coefficient, viscosity, ionic Conductivity, and Molar Conductivity have been estimated, together with the linear fitting parameters for the density. The self-diffusion coefficients determined for the individual ions by pulsed-field-gradient spin−echo NMR method exhibit higher values for the cation compared with the anion over a wide temperature range, even if its radius is larger than that of the anionic radii. The summation of the cationic and anionic diffusion coefficients for the RT...
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Pulsed-gradient spin-echo 1H and 19F NMR ionic diffusion coefficient, viscosity, and ionic Conductivity of non-chloroaluminate room-temperature ionic liquids
Journal of Physical Chemistry B, 2001Co-Authors: Akihiro Noda, Kikuko Hayamizu, Masayoshi WatanabeAbstract:Room-temperature ionic liquids, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4), 1-ethyl-3-methylimidazolium 1-butylpyridinium tetrafluoroborate (BPBF4), and 1-butylpyridinium bis(trifluoromethylsulfonyl)imide (BPTFSI), were prepared and characterized. The thermal property, density, self-diffusion coefficient of the anions and cations, viscosity, and ionic Conductivity were measured for these ionic liquids in wide temperature ranges. A pulsed-gradient spinecho NMR method was used to independently measure self-diffusion coefficients of the anions (19F NMR) and the cations (1H NMR). The results indicate that the cations diffuse almost equally to the anion in EMIBF4 and BPBF4, whereas they diffuse faster than the anion in EMITFSI and BPTFSI. The summation of the cationic and anionic diffusion coefficients for each ionic liquid follows the order EMITFSI > EMIBF4 > BPTFSI > BPBF4, under an isothermal condition. The order of the magnitude of the diffusion coefficient well contrasts with that of the viscosity for each ionic liquid. The temperature dependencies of the self-diffusion coefficient, viscosity, and ionic Conductivity obey the VogelTammanFulcher (VTF) equation, and the VTF parameters were presented. Relationships among the self-diffusion coefficient, viscosity, and Molar Conductivity were analyzed in terms of the StokesEinstein equation and the NernstEinstein equation. The most interesting feature of the relationships is that the ratios of the Molar Conductivity, determined by complex impedance measurements, to that calculated from the NMR diffusion coefficients, range from 0.6 to 0.8 for EMIBF4 and BPBF4, whereas the ratios range from 0.3 to 0.5 for EMITFSI and BPTFSI. This difference could be understood by taking the ionic association into consideration for EMITFSI and BPTFSI.
Makoto Ue - One of the best experts on this subject based on the ideXlab platform.
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ionic radius of cf 3 so 2 3 c and applicability of stokes law to its propylene carbonate solution
Journal of The Electrochemical Society, 1996Co-Authors: Makoto UeAbstract:The ionic radius of (CF 3 SO 2 ) 3 C - was calculated to be 0.375 nm from its van der Waals volume, which was obtained by molecular mechanics calculations with the aid of its crystallogaphic data. This radius was correlated with its single ion limiting Molar Conductivity in propylene carbonate at 25°C, and it was proven that this anion also nearly follows the behavior of perfect slip in Stokes law, as is observed for other popular anions for lithium battery applications
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ionic radius of cf sub 3 so sub 2 sub 3 c sup minus and applicability of stokes law to its propylene carbonate solution
Journal of The Electrochemical Society, 1996Co-Authors: Makoto UeAbstract:The ionic radius of (Cf{sub 3}SO{sub 2}){sub 3}C{+-}{sup {minus}} was calculated to be 0.375 nm from its van der Waals volume, which was obtained by molecular mechanics calculations with the aid of its crystallographic data. This radius was correlated with its single ion limiting Molar Conductivity in propylene carbonate at 25 C, and it was proven that this anion also nearly followed the behavior of perfect slip in Stokes law, as is observed for other popular anions for lithium battery applications.
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Ionic radius of (CF{sub 3}SO{sub 2}){sub 3}C{sup {minus}} and applicability of Stokes law to its propylene carbonate solution
Journal of The Electrochemical Society, 1996Co-Authors: Makoto UeAbstract:The ionic radius of (Cf{sub 3}SO{sub 2}){sub 3}C{+-}{sup {minus}} was calculated to be 0.375 nm from its van der Waals volume, which was obtained by molecular mechanics calculations with the aid of its crystallographic data. This radius was correlated with its single ion limiting Molar Conductivity in propylene carbonate at 25 C, and it was proven that this anion also nearly followed the behavior of perfect slip in Stokes law, as is observed for other popular anions for lithium battery applications.
Venkat Ganesan - One of the best experts on this subject based on the ideXlab platform.
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influence ofhost polarity on correlating salt concentration molecular weight and Molar Conductivity in polymer electrolytes
ACS Macro Letters, 2019Co-Authors: Bill K Wheatle, Erick Fuentes, Nathaniel A Lynd, Venkat GanesanAbstract:We use coarse-grained molecular dynamics simulations to study the effect of salt concentration and host polymer molecular weight on ion transport in polymer electrolytes. We find that increasing salt concentration or molecular weight similarly slows polymer dynamics across a wide range of host polarities, and that the resulting relaxation times display a correlation to the product of the salt concentration and polymer molecular weight. However, we find that Molar Conductivity only decreases with polymer dynamics at high polarities but is uncorrelated with the latter at low polarities. We attribute such differences to the variation in ionic aggregation between high and low polarity electrolytes. At low polarity, ionic dissociation significantly increases with molecular weight and salt concentration, offsetting the slowdown in polymer dynamics and yielding the observed insensitivity of Molar Conductivity. However, at high polarity, ions are mostly dissociated, independent of either molecular weight or salt ...
Małgorzata Jóźwiak - One of the best experts on this subject based on the ideXlab platform.
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Molar Conductivity and association constants of sodium salts of selected cinnamic acids in water at temperatures from 288.15 to 318.15 K
Journal of Molecular Liquids, 2019Co-Authors: Marta Stańczyk, Agnieszka Boruń, Małgorzata JóźwiakAbstract:Abstract The electrical conductivities of aqueous solutions of sodium salts of cinnamic acid, 4-hydroxycinnamic (p-coumaric) acid, 3,4-dihydroxycinnamic (caffeic) acid, 4-hydroxy-5-methoxycinnamic (ferulic) acid and 3,5-dimethoxy-4-hydroxycinnamic (sinapinic) acid were measured over the temperature range (T) of 288.15 to 318.15 K at 5 K intervals. The limiting Molar Conductivity Λ m o and ionic association constants (KAo) were obtained using the low concentration Chemical Model (lcCM). The limiting ionic Conductivity and the Eyring's activation enthalpy of charge transport of the investigated anions were determined.
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conductance studies of aqueous solutions of sodium salts of selected benzoic acid derivatives at temperatures from 288 15 to 318 15 k
Journal of Molecular Liquids, 2019Co-Authors: Marta Stanczyk, Agnieszka Borun, Małgorzata JóźwiakAbstract:Abstract The electrical conductivities of aqueous solutions of sodium salts of benzoic acid, 2-hydroxybenzoic (o-salicylic) acid, 3-hydroxybenzoic (m-salicylic) acid, 4-hydroxybenzoic (p-salicylic) acid, 3,4-dihydroxybenzoic (protocatechuic) acid, 4-hydroxy-3-methoxybenzoic (vanillic) acid and 4-hydroxy-3,5-dimethoxybenzoic (syringic) acid were measured over a temperature range (T) of 288.15 to 318.15 K and a concentration range (c) of ~1 · 10−4 to ~1,5 · 10−2 mol·dm−3. The results were analyzed with Barthel's low concentration Chemical Model (lcCM) to obtain the ionic association constants (KAo) and the limiting Molar Conductivity (Λmo) of the electrolytes. The limiting ionic Conductivity and hydrodynamic radius of the investigated anions were determined, as well as the value for Eyring's activation enthalpy of charge transport. The study also analyzes and discusses the influence of hydrolysis of the salts on their limiting Molar Conductivity.
Wang Wei-dong - One of the best experts on this subject based on the ideXlab platform.
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Determination of the Infinite Dilution Molar Conducvity of ErCl_3 in DMF
Journal of Xianyang Teachers College, 2020Co-Authors: Wang Wei-dongAbstract:The infinite dilution Molar Conductivity of ErCl3 from temperature 293K to 313K was determined in solvent DMF. The Molar Conductivity λof ErCl3 was calculated The λ0 in DMF could be obtained by using extrapolation method. The relationship between infinite dilution Molar Conductivity andtemperature was discussed in this paper.
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Study on Thermodynamic Properties of LiCl in 2-Propanol Solvent
Journal of Salt Lake Research, 2020Co-Authors: Wang Wei-dongAbstract:The electric Conductivity of LiCl in 2-Propanol solvent was measured using Conductivity meter at 288～308 K.The Molar Conductivity of LiCl was calculated with the help of the formula.The data were linear fitted with the software of Origin according to Kohlrausch empirical formula.And the Molar Conductivity at infinite dilution of LiCl was obtained by the extrapolation method.The changes of the Conductivity,Molar Conductivity,activity coefficient and relative partial Molar free energy of LiCl with concentration and temperature of the solution were discussed.Moreover,the influence of temperature on Molar Conductivity at infinite dilution of LiCl was also discussed.
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Study on the Conductivity of NaCl in DMF and 1,2-Propanediol Mixture Solvent
Journal of Salt Lake Research, 2020Co-Authors: Wang Wei-dongAbstract:The electrical Conductivity of NaCl in DMF and 1,2-propanediol at 283K to 308K were determined, based on which, the Molar Conductivity of NaCl in the mixture solvent was calculated. By using the Kohlrausch formula, and the Origin software, the Molar Conductivity was plotted against the square root of concentration at different temperature. By extrapolating the curves to zero concentration, the Molar conductivities of NaCl at infinite dilution in the mixed solvent at different temperatures were obtained. The relat ionships of the Conductivity, Molar Conductivity, and Molar Conductivity at infinite dilution of NaCl in DMF and 1,2-propanediol mixture solvent were also discussed.
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Study on the Conductivity of ErCl_3,DyCl_3,NdCl_3 and YCl_3 in H_2O at 298 K
Journal of Jishou University, 2020Co-Authors: Wang Wei-dongAbstract:The electric Conductivity of rare earths salt ErCl_3,DyCl_3,NdCl_3 and YCl_3 was determined in H_2O at 298 K by Conductivity meter,and the Molar Conductivity was calculated according to the related formula.The effect of concentration on the electric Conductivity and Molar Conductivity was discussed.With the increasing concentration of rare earths salt solution,the Conductivity proportion of rare earths salt in the solution got higher and the Molar Conductivity of rare earths salt got lower.
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Study on the Conductivity of rare earths salt NdCl_3 in DMF and H_2O at 298 K
Journal of Baoji College of Arts and Science, 2020Co-Authors: Wang Wei-dongAbstract:Determined electrice Conductivity of rare earths salt NdCl_3 in DMF and H_2O at 298K ,The use of formula has calculated the Molar Conductivity of rare earths salt NdCl_3 in DMF and H_2O. The use of Origin Software has made the diagram to push outside and calculated the Molar Conductivity at infinite clilutionλ_0=300.01 S·cm~2·mol~(-1) of NdCl_3 in DMF and H_2O obtained by linear fiting, and discussed the effect of the electrice Conductivity and the Molar Conductivity of rare earths salt NdCl_3 in DMF and H_2O with concentration at 298 K. With the inereasing of the concentration of rare earths salt in the solution at 298 K, the Conductivity proportion of rare earths salt in the solution got higher and the Molar Conductivity got lower.
