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Author: search.filters.author.Ramjugernath, DereshHas files: No

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    Application of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ionic liquid for the different types of separations problem: Activity coefficients at infinite dilution measurements using gas-liquid chromatography technique
    (Elsevier, 2016) Singh, Sangeeta; Bahadur, Indra; Naidoo, Paramespri; Ramjugernath, Deresh
    The present work focussed on application of the environmental friendly 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([BMIM]+[Tf2N]−) ionic liquid for the separations of (alkane/aromatic), (al-kane/alk-1-ene), (cycloalkane/aromatic) and (water/alkan-1-ol) using gas-liquid chromatography (GLC) tech-nique. In this reason the activity coefficients at infinite dilution, γ∞13, for 31 organic solutes (alkanes, cycloalkanes, alkenes, alkynes, aromatics, alkanol and ketones) and water in ionic liquid were measured at temper-atures of (323.15, 333.15, 343.15, 353.15 and 363.15) K. Stationary phase loadings of (42.83 and 68.66) % by mass were used to ensure repeatability of measurements. Density and viscosity values were measured to confirm the purity of ionic liquid. Partial molar excess enthalpies at infinite dilution, ΔH1,∞, were also determined. The selectiv-ities, Sij∞, and capacities, kj∞, were determined for the above separations. The separating ability of the investigated ionic liquid was compared with previously investigated ionic liquids and industrial solvents such as sulfolane, n-methyl-2-pyrrolidine (NMP) and n-formylmorpholine (NFM).
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    Influence of the alkyl group on thermophysical properties of carboxylic acids in 1-butyl-3-methylimidazolium thiocyanate ionic liquid at various temperatures
    (Elsevier, 2015) Redhi, Gan G.; Ebenso, Eno E.; Singh, Suren; Bahadur, Indra; Ramjugernath, Deresh
    In the present study, influence of the alkyl group and temperature on the interactions between the carboxylic acid and ionic liquid (IL) mixtures were discussed in term of density and sound velocity measurements. The IL used in this study was 1-butyl-3-methylimidazolium thiocyanate ([BMIM]+[SCN]−). The density (ρ), and sound velocity (u), of the IL, acetic acid, propionic acid, and their corresponding binary systems {[BMIM]+[SCN]− (x1) + acetic or propionic acid (x2)} have been measured at T = (293.15, 298.15, 303.15, 308.15 and 313.15) K and at p = 0.1 MPa. The excess molar volumes, View the MathML sourceVmE, isentropic compressibility, κs, and deviation in isentropic compressibility, Δκs, were calculated using experimental density and sound velocity data, respectively. The Redlich–Kister polynomial equation was used to fit the excess/deviation properties. These results are useful for describing the intermolecular interactions that exist between the IL and carboxylic acid mixtures.
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    Density and speed of sound of 1-ethyl-3-methylimidazolium ethyl sulphate with acetic or propionic acid at different temperatures
    (Elsevier, 2014-11) Singh, Sangeeta; Bahadur, Indra; Redhi, Gan G.; Ramjugernath, Deresh; Ebenso, Eno, E.
    In this work, new density, ρ, and speed of sound, u, were measured for IL, acetic acid, propionic acid, and their binary systems {IL (x1) + acetic or propionic acid (x2)} at 293.15, 298.15, 303.15, 308.15 and 313.15 K under at-mospheric pressure. The IL used in this study was 1-ethyl-3-methylimidazolium ethyl sulphate ([EMIM]+[EtSO4]−). The derived properties such as excess molar volumes, Vm, isentropic compressibility, κs, and deviation in isentropic compressibility, Δκs, were calculated using experimental density and speed of sound data, respectively. Derived properties such as excess molar volumes, Vm, and deviation in isentropic com-pressibility, Δκs, data were fitted to the Redlich–Kister polynomial equation. The measured and calculated data were interpreted on the basis of intermolecular interactions and structural effects between like and unlike mol-ecules upon mixing.
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    Density, speed of sound, and refractive index measurements for the binary systems (butanoic acid + propanoic acid, or 2-methyl-propanoic acid) at T = (293.15 to 313.15) K
    (Elsevier, 2012-09-17) Bahadur, Indra; Deenadayalu, Nirmala; Naidoo, Paramespri; Ramjugernath, Deresh
    Density, speed of sound, and refractive index for the binary systems (butanoic acid + propanoic acid, or 2-methyl-propanoic acid) were measured over the whole composition range and at T = (293.15, 298.15, 303.15, 308.15, and 313.15) K. The excess molar volumes, isentropic compressibilities, excess isentropic compressibilities, molar refractions, and deviation in refractive indices were also calculated by using the experimental densities, speed of sound, and refractive indices data, respectively. The Redlich–Kister smoothing polynomial equation was used to fit the excess molar volume, excess isentro- pic compressibility and deviation in refractive index data. The thermodynamic properties have been discussed in terms of intermolecular interactions between the components of the mixtures.
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    Ternary excess molar volumes of {methyltrioctylammonium bis(trifluoromethylsulfonyl)imide + ethanol + methyl acetate, or ethyl acetate} systems at T = (298.15, 303.15, and 313.15) K
    (Elsevier, 2010-01-28) Gwala, Nobuhle V.; Deenadayalu, Nirmala; Tumba, Kaniki; Ramjugernath, Deresh
    The activity coefficient at infinite dilution for 30 solutes: alkanes, alkenes, cycloalkanes, alkynes, ketones, alcohols, and aromatic compounds was determined from gas–liquid chromatography (glc) measurements at three temperatures (303.15, 313.15, and 323.15) K. The ionic liquid: trioctylmethylammonium bis(trifluoromethylsulfonyl)imide, was used as the stationary phase. For each temperature, values were determined using two columns with different mass percent packing of the ionic liquid. The selectivity value was calculated from the to determine the suitability of the solvent as a potential entrainer for extractive distillation in the separation of an hexane/benzene mixture, indicative of a typical industrial separation problem for benchmarking purposes.
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    Solid–liquid equilibria measurements for binary systems comprising (butyric acid + propionic or pentanoic acid) and (heptanoic acid + propionic or butyric or pentanoic or hexanoic acid)
    (Elsevier, 2013-02) Ramjugernath, Deresh; Deenadayalu, Nirmala; Naidoo, Paramespri; Ngema, Peterson Thokozani; Reddy, Prashant; Bahadur, Indra; Tadie, Margreth
    Solid–liquid equilibria (SLE) measurements have been undertaken for carboxylic acid systems comprising (butyric acid + propionic or pentanoic acid) and (heptanoic acid + propionic or butyric or pentanoic or hexanoic acid) via a synthetic method using two complementary pieces of equipment. The measurements have been obtained at atmospheric pressure and over the temperature range of (225.6 to 270.7) K. All the acid mixtures exhibit a eutectic point in their respective phase diagrams, which have been determined experimentally. The estimated maximum uncertainties in the reported temperatures and compositions are ±1 K and ±0.0006 mole fraction, respectively. The experimental data have been satisfactorily correlated with the Wilson and NRTL activity coefficient models.