Environmentally friendly solutions of liquid poly(ethylene glycol) and imidazolium based ionic liquids with bistriflamide and triflate anions: Volumetric and viscosity studies

Ion self-diffusion coefficients (D Si ) for [EMIM][CF 3 SO 3 ] and [chol][Tf 2 N] and cation self-diffusion coefficients for [CH 3 SO 3 ] − , [TCB] − , and [FAP] − salts of [EMIM] + are reported together with ancillary data allowing calculation of velocity cross-correlation (VCC or f ij ), distinct diffusion (D d ij ) and Laity resistance coefficients (r ij ). Comparison of ion Stokes−Einstein−Sutherland (SES) exponents is a useful test of experimental consistency. New analysis shows the viscosity (η) and molar conductivity (Λ) of [EMIM][CH 3 SO 3 ] and [EMIM][TCB] do not show the dynamic crossovers previously reported. Nor do D S and η for the comparison substance propylene carbonate. For all the ionic liquids, D S+ > D S-. Data show fractional SES (D Si -η, D d ij -η) and Walden (Λ−η) plots. The Nernst−Einstein parameter, Δ, for [EMIM][FAP] is approximately zero, implying the relative velocity of any ion pair selected randomly is uncorrelated with those of other distinct pairs. For the other ionic liquids, the relative pair velocities are anticorrelated. VCC values for the [EMIM] + salts except [EMIM] [FAP] lie in the order |f +− | < |f ++ | < | f −− |; that is, the anticorrelation is smallest for the unlike ion interactions: correspondingly, r ++ < r −− < r +− . For [EMIM][FAP], | f ++ | < |f +− | < |f −− |, with f +− ∼ ( f ++ + f −− )/2 and r +− 2 ∼r ++ r −− , consistent with Δ ∼ 0.

Section: ■ Resultsmentioning

confidence: 83%

Self-Diffusion Coefficients and Related Transport Properties for a Number of Fragile Ionic Liquids

Harris

Kanakubo

2016

“…Densities ρ of pure substances were measured using an Anton Paar DMA 5000 digital vibrating U-tube densimeter with a procedure described earlier. 27,28 The temperature in the cell was regulated to ±0.001 K by a built in solid-state thermostat. The experimental uncertainty in density is about ±1·10 −2 kg·m −3 .…”

Section: Methodsmentioning

confidence: 99%

Cloud Point Phenomena in the (Aniline or N,N-Dimethylaniline + Water) Solutions, and Cosolvent Effects of Liquid Poly(ethylene glycol) Addition: Experimental Measurements and Modeling

Grozdanić

Soldatović²,

Šerbanović

et al. 2015

In this work, liquid phase behavior (cloud point phenomena) was studied for two binary and four aqueous pseudobinary systems containing aniline or N,N-dimethylaniline and poly(ethylene glycol) 200 or poly(ethylene glycol) 400, (PEG200 and PEG400, respectively) in the temperature range T = (290.15 to 351.15) K and an ambient pressure of 0.1 MPa. Experimental data (cloud-points) were obtained by the visual cloud point method. The studied systems exhibit an upper critical solution temperature (UCST) type of phase behavior and the immiscibility increases with increasing the average molar mass of poly(ethylene glycols). PEG200/PEG400 showed as a good cosolvent for aniline in water. The experimental data were correlated using non-random two-liquid model (NRTL) with one form of temperature dependent parameters.

“…Pd-catalyzed reactions (the importance of these can be seen in the 2010 Nobel prize award for their discovery) have also been carried out in PEG under both homocatalytic and heterocatalytic conditions where Pd is immobilized onto a porous silica material. − PEGs have also been successfully used as components in deep eutectic solvents. − Despite all of these successes, there are only limited experimental and theoretical studies on the dynamics of neat PEG. − Experimental physicochemical properties of PEGs are needed to further this effort. In this respect, densities and viscosities have been repeatedly reported for several polydisperse PEGs usually as part of studies on binary mixtures involving polydisperse PEGs. − The polydisperse PEGs are composed of mixtures of PEG oligomers with approximately a Gaussian mole fraction distribution around the mean chain length. ,, It is likely that the exact mole fraction distribution may vary from vendor to vendor and possibly even from batch to batch. Unfortunately, a composition analysis of polydisperse PEGs is typically not included in the above cited studies.…”

Section: Introductionmentioning

confidence: 99%

Densities, Viscosities, and Self-Diffusion Coefficients of Ethylene Glycol Oligomers

Hoffmann

Horowitz

Gutmann³

et al. 2021

Polyethylene glycol (PEG) is gaining interest as an alternative green solvent in chemical synthesis and processing. This report presents density and viscosity data from 293.15 K to 358.15 K as well as self-diffusion coefficient data from 298.15 K to 358.15 K for oligomers of PEG from di-to nonaethylene glycol. The results were obtained by extrapolation from measurement series where water, the most common impurity in PEGs, was intentionally added in several increments. The obtained results are carefully compared to literature data, which are widely available only for density and viscosity, and only for the lower oligomers. Densities are found to be linearly dependent on temperatures for all studied oligomers. The temperature dependence of viscosity and self-diffusion coefficients show only slight deviations from the Arrhenius equation over the investigated temperature range. The activation energies obtained from the viscosity data agree well with the activation energies from the self-diffusion coefficient data and appear to be linearly dependent with respect to the number of ethylene oxide repeat units in the PEG oligomer. This linearity combined with the observation that the pre-exponential factor appears to be the same for all studied oligomers may serve as a tool to estimate viscosities and self-diffusion coefficients for higher oligomers within the investigated temperature range. The densities of the oligomers all fall within a rather narrow range without a clear trend in homologous series.