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Nkululeko Nkosi - One of the best experts on this subject based on the ideXlab platform.

  • Activity coefficients at infinite dilution of various organic solutes in the deep eutectic solvent (Tetramethylammonium Chloride + 1,6 hexanediol in the 1:1 molar ratio)
    Elsevier, 2019
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Deep eutectic solvents (DESs) have emerged as potential green and low-cost substitutes to ionic liquids in various chemical processes. In this study, experimental activity coefficients at infinite dilution for 22 organic solutes were measured in the DES consisting of Tetramethylammonium Chloride and 1,6 hexanediol (1:1 molar ratio) by gas-liquid chromatography at four temperatures within the range of (313.15–343.15) K at 101.3 kPa. The effect of the molecular structure of the solute on limiting activity coefficient was also examined. From infinite dilution activity coefficients, limiting partial molar excess enthalpies, entropies and Gibbs free energies were calculated to gain insight into solute-DES interactions. It emerged that the strongest soulte-DES interactions were associated with pyridine, thiophene and methyl acetate. Subsequently, limiting selectivities and capacities were calculated for various separation problems to evaluate the potential use of the DES as a separation agent. The best separation performance of the investigated DES was obtained for mixtures consisting of n-alkanes and thiophene or pyridine. For this reason, it was concluded that the DES (Tetramethylammonium Chloride + 1,6 hexanediol in the 1:1 molar ratio) is a credible candidate to be considered for the denitrogenation as well as the desulphurisation of transportation fuels. Keywords: Deep eutectic solvent, Activity coefficient at infinite dilution, Enthalpies at infinite dilution, Gas-liquid chromatography, Separatio

  • activity coefficients at infinite dilution of various organic solutes in the deep eutectic solvent Tetramethylammonium Chloride 1 6 hexanediol in the 1 1 molar ratio
    South African Journal of Chemical Engineering, 2019
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Abstract Deep eutectic solvents (DESs) have emerged as potential green and low-cost substitutes to ionic liquids in various chemical processes. In this study, experimental activity coefficients at infinite dilution for 22 organic solutes were measured in the DES consisting of Tetramethylammonium Chloride and 1,6 hexanediol (1:1 molar ratio) by gas-liquid chromatography at four temperatures within the range of (313.15–343.15) K at 101.3 kPa. The effect of the molecular structure of the solute on limiting activity coefficient was also examined. From infinite dilution activity coefficients, limiting partial molar excess enthalpies, entropies and Gibbs free energies were calculated to gain insight into solute-DES interactions. It emerged that the strongest soulte-DES interactions were associated with pyridine, thiophene and methyl acetate. Subsequently, limiting selectivities and capacities were calculated for various separation problems to evaluate the potential use of the DES as a separation agent. The best separation performance of the investigated DES was obtained for mixtures consisting of n-alkanes and thiophene or pyridine. For this reason, it was concluded that the DES (Tetramethylammonium Chloride + 1,6 hexanediol in the 1:1 molar ratio) is a credible candidate to be considered for the denitrogenation as well as the desulphurisation of transportation fuels.

  • Tetramethylammonium Chloride glycerol deep eutectic solvent as separation agent for organic liquid mixtures assessment from experimental limiting activity coefficients
    Fluid Phase Equilibria, 2018
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Abstract Solute retention data acquired by gas-liquid chromatography were used to determine the activity coefficients at infinite dilution for 24 organic solutes in the deep eutectic solvent (DES) consisting of Tetramethylammonium Chloride and glycerol in a molar ratio of 1.001:2. The organic solutes included alk-1-anes, alk-1-enes, alk-1-ynes, cycloalkanes, alkanols, alkylbenzenes, ketones, esters and heterocyclics. The measurements were undertaken at four different temperatures, viz T = (313.15, 323.15, 333.15 and 343.15) K with an estimated uncertainty of ±3.8%. From the experimental infinite dilution activity coefficient data, the values of partial molar excess enthalpy at infinite dilution were calculated using Gibbs Helmholtz relationship. Limiting selectivity and capacity values were also calculated from experimental limiting activity coefficients and compared to those of other separation agents, including other deep eutectic solvents, ionic liquids and industrial molecular agents. Results obtained in this study indicate that Tetramethylammonium Chloride + glycerol DES can potentially be used as an alternative solvent for nitrogen and sulphur removal from transportation fuels as well as the separation of cycloalkanes, aromatics and esters from light alkanols.

  • measurements of activity coefficient at infinite dilution for organic solutes in Tetramethylammonium Chloride ethylene glycol deep eutectic solvent using gas liquid chromatography
    Fluid Phase Equilibria, 2018
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Abstract Deep eutectic solvents (DESs) are considered as the new ionic liquids (ILs) analogues that have emerged as potential alternative ‘green’ solvents, for a diversity of applications. In this study, a type III DES based on ammonium salt was investigated as an alternative solvent to currently employed conventional organic solvents in separation processes. Activity coefficients at infinite dilution, γ 13 ∞ for 19 organic solutes in the Tetramethylammonium Chloride + ethylene glycol DES were measured by the gas-liquid chromatography (GLC) method at four temperatures in the range from (313.15–343.15) K. Experimental measurements were undertaken with an overall uncertainty of ±5.4%. The effect of the structure of the solutes on γ 13 ∞ was also investigated. For all investigated solutes, Gibbs helmholtz relationship was utilised to derive partial molar excess enthalpy values at infinite dilution ( Δ H i E , ( ∞ ) ) from experimental limiting activity coefficient data. From selectivity ( S i j ∞ ) and capacity ( k j ∞ ) values at infinte dilution, it was concluded that the investigated DES has the potential to replace a number of industrial solvents for the separation of various industrial mixtures.

Suresh Ramsuroop - One of the best experts on this subject based on the ideXlab platform.

  • Activity coefficients at infinite dilution of various organic solutes in the deep eutectic solvent (Tetramethylammonium Chloride + 1,6 hexanediol in the 1:1 molar ratio)
    Elsevier, 2019
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Deep eutectic solvents (DESs) have emerged as potential green and low-cost substitutes to ionic liquids in various chemical processes. In this study, experimental activity coefficients at infinite dilution for 22 organic solutes were measured in the DES consisting of Tetramethylammonium Chloride and 1,6 hexanediol (1:1 molar ratio) by gas-liquid chromatography at four temperatures within the range of (313.15–343.15) K at 101.3 kPa. The effect of the molecular structure of the solute on limiting activity coefficient was also examined. From infinite dilution activity coefficients, limiting partial molar excess enthalpies, entropies and Gibbs free energies were calculated to gain insight into solute-DES interactions. It emerged that the strongest soulte-DES interactions were associated with pyridine, thiophene and methyl acetate. Subsequently, limiting selectivities and capacities were calculated for various separation problems to evaluate the potential use of the DES as a separation agent. The best separation performance of the investigated DES was obtained for mixtures consisting of n-alkanes and thiophene or pyridine. For this reason, it was concluded that the DES (Tetramethylammonium Chloride + 1,6 hexanediol in the 1:1 molar ratio) is a credible candidate to be considered for the denitrogenation as well as the desulphurisation of transportation fuels. Keywords: Deep eutectic solvent, Activity coefficient at infinite dilution, Enthalpies at infinite dilution, Gas-liquid chromatography, Separatio

  • activity coefficients at infinite dilution of various organic solutes in the deep eutectic solvent Tetramethylammonium Chloride 1 6 hexanediol in the 1 1 molar ratio
    South African Journal of Chemical Engineering, 2019
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Abstract Deep eutectic solvents (DESs) have emerged as potential green and low-cost substitutes to ionic liquids in various chemical processes. In this study, experimental activity coefficients at infinite dilution for 22 organic solutes were measured in the DES consisting of Tetramethylammonium Chloride and 1,6 hexanediol (1:1 molar ratio) by gas-liquid chromatography at four temperatures within the range of (313.15–343.15) K at 101.3 kPa. The effect of the molecular structure of the solute on limiting activity coefficient was also examined. From infinite dilution activity coefficients, limiting partial molar excess enthalpies, entropies and Gibbs free energies were calculated to gain insight into solute-DES interactions. It emerged that the strongest soulte-DES interactions were associated with pyridine, thiophene and methyl acetate. Subsequently, limiting selectivities and capacities were calculated for various separation problems to evaluate the potential use of the DES as a separation agent. The best separation performance of the investigated DES was obtained for mixtures consisting of n-alkanes and thiophene or pyridine. For this reason, it was concluded that the DES (Tetramethylammonium Chloride + 1,6 hexanediol in the 1:1 molar ratio) is a credible candidate to be considered for the denitrogenation as well as the desulphurisation of transportation fuels.

  • Tetramethylammonium Chloride glycerol deep eutectic solvent as separation agent for organic liquid mixtures assessment from experimental limiting activity coefficients
    Fluid Phase Equilibria, 2018
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Abstract Solute retention data acquired by gas-liquid chromatography were used to determine the activity coefficients at infinite dilution for 24 organic solutes in the deep eutectic solvent (DES) consisting of Tetramethylammonium Chloride and glycerol in a molar ratio of 1.001:2. The organic solutes included alk-1-anes, alk-1-enes, alk-1-ynes, cycloalkanes, alkanols, alkylbenzenes, ketones, esters and heterocyclics. The measurements were undertaken at four different temperatures, viz T = (313.15, 323.15, 333.15 and 343.15) K with an estimated uncertainty of ±3.8%. From the experimental infinite dilution activity coefficient data, the values of partial molar excess enthalpy at infinite dilution were calculated using Gibbs Helmholtz relationship. Limiting selectivity and capacity values were also calculated from experimental limiting activity coefficients and compared to those of other separation agents, including other deep eutectic solvents, ionic liquids and industrial molecular agents. Results obtained in this study indicate that Tetramethylammonium Chloride + glycerol DES can potentially be used as an alternative solvent for nitrogen and sulphur removal from transportation fuels as well as the separation of cycloalkanes, aromatics and esters from light alkanols.

  • measurements of activity coefficient at infinite dilution for organic solutes in Tetramethylammonium Chloride ethylene glycol deep eutectic solvent using gas liquid chromatography
    Fluid Phase Equilibria, 2018
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Abstract Deep eutectic solvents (DESs) are considered as the new ionic liquids (ILs) analogues that have emerged as potential alternative ‘green’ solvents, for a diversity of applications. In this study, a type III DES based on ammonium salt was investigated as an alternative solvent to currently employed conventional organic solvents in separation processes. Activity coefficients at infinite dilution, γ 13 ∞ for 19 organic solutes in the Tetramethylammonium Chloride + ethylene glycol DES were measured by the gas-liquid chromatography (GLC) method at four temperatures in the range from (313.15–343.15) K. Experimental measurements were undertaken with an overall uncertainty of ±5.4%. The effect of the structure of the solutes on γ 13 ∞ was also investigated. For all investigated solutes, Gibbs helmholtz relationship was utilised to derive partial molar excess enthalpy values at infinite dilution ( Δ H i E , ( ∞ ) ) from experimental limiting activity coefficient data. From selectivity ( S i j ∞ ) and capacity ( k j ∞ ) values at infinte dilution, it was concluded that the investigated DES has the potential to replace a number of industrial solvents for the separation of various industrial mixtures.

Kaniki Tumba - One of the best experts on this subject based on the ideXlab platform.

  • Activity coefficients at infinite dilution of various organic solutes in the deep eutectic solvent (Tetramethylammonium Chloride + 1,6 hexanediol in the 1:1 molar ratio)
    Elsevier, 2019
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Deep eutectic solvents (DESs) have emerged as potential green and low-cost substitutes to ionic liquids in various chemical processes. In this study, experimental activity coefficients at infinite dilution for 22 organic solutes were measured in the DES consisting of Tetramethylammonium Chloride and 1,6 hexanediol (1:1 molar ratio) by gas-liquid chromatography at four temperatures within the range of (313.15–343.15) K at 101.3 kPa. The effect of the molecular structure of the solute on limiting activity coefficient was also examined. From infinite dilution activity coefficients, limiting partial molar excess enthalpies, entropies and Gibbs free energies were calculated to gain insight into solute-DES interactions. It emerged that the strongest soulte-DES interactions were associated with pyridine, thiophene and methyl acetate. Subsequently, limiting selectivities and capacities were calculated for various separation problems to evaluate the potential use of the DES as a separation agent. The best separation performance of the investigated DES was obtained for mixtures consisting of n-alkanes and thiophene or pyridine. For this reason, it was concluded that the DES (Tetramethylammonium Chloride + 1,6 hexanediol in the 1:1 molar ratio) is a credible candidate to be considered for the denitrogenation as well as the desulphurisation of transportation fuels. Keywords: Deep eutectic solvent, Activity coefficient at infinite dilution, Enthalpies at infinite dilution, Gas-liquid chromatography, Separatio

  • activity coefficients at infinite dilution of various organic solutes in the deep eutectic solvent Tetramethylammonium Chloride 1 6 hexanediol in the 1 1 molar ratio
    South African Journal of Chemical Engineering, 2019
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Abstract Deep eutectic solvents (DESs) have emerged as potential green and low-cost substitutes to ionic liquids in various chemical processes. In this study, experimental activity coefficients at infinite dilution for 22 organic solutes were measured in the DES consisting of Tetramethylammonium Chloride and 1,6 hexanediol (1:1 molar ratio) by gas-liquid chromatography at four temperatures within the range of (313.15–343.15) K at 101.3 kPa. The effect of the molecular structure of the solute on limiting activity coefficient was also examined. From infinite dilution activity coefficients, limiting partial molar excess enthalpies, entropies and Gibbs free energies were calculated to gain insight into solute-DES interactions. It emerged that the strongest soulte-DES interactions were associated with pyridine, thiophene and methyl acetate. Subsequently, limiting selectivities and capacities were calculated for various separation problems to evaluate the potential use of the DES as a separation agent. The best separation performance of the investigated DES was obtained for mixtures consisting of n-alkanes and thiophene or pyridine. For this reason, it was concluded that the DES (Tetramethylammonium Chloride + 1,6 hexanediol in the 1:1 molar ratio) is a credible candidate to be considered for the denitrogenation as well as the desulphurisation of transportation fuels.

  • Tetramethylammonium Chloride glycerol deep eutectic solvent as separation agent for organic liquid mixtures assessment from experimental limiting activity coefficients
    Fluid Phase Equilibria, 2018
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Abstract Solute retention data acquired by gas-liquid chromatography were used to determine the activity coefficients at infinite dilution for 24 organic solutes in the deep eutectic solvent (DES) consisting of Tetramethylammonium Chloride and glycerol in a molar ratio of 1.001:2. The organic solutes included alk-1-anes, alk-1-enes, alk-1-ynes, cycloalkanes, alkanols, alkylbenzenes, ketones, esters and heterocyclics. The measurements were undertaken at four different temperatures, viz T = (313.15, 323.15, 333.15 and 343.15) K with an estimated uncertainty of ±3.8%. From the experimental infinite dilution activity coefficient data, the values of partial molar excess enthalpy at infinite dilution were calculated using Gibbs Helmholtz relationship. Limiting selectivity and capacity values were also calculated from experimental limiting activity coefficients and compared to those of other separation agents, including other deep eutectic solvents, ionic liquids and industrial molecular agents. Results obtained in this study indicate that Tetramethylammonium Chloride + glycerol DES can potentially be used as an alternative solvent for nitrogen and sulphur removal from transportation fuels as well as the separation of cycloalkanes, aromatics and esters from light alkanols.

  • measurements of activity coefficient at infinite dilution for organic solutes in Tetramethylammonium Chloride ethylene glycol deep eutectic solvent using gas liquid chromatography
    Fluid Phase Equilibria, 2018
    Co-Authors: Nkululeko Nkosi, Kaniki Tumba, Suresh Ramsuroop
    Abstract:

    Abstract Deep eutectic solvents (DESs) are considered as the new ionic liquids (ILs) analogues that have emerged as potential alternative ‘green’ solvents, for a diversity of applications. In this study, a type III DES based on ammonium salt was investigated as an alternative solvent to currently employed conventional organic solvents in separation processes. Activity coefficients at infinite dilution, γ 13 ∞ for 19 organic solutes in the Tetramethylammonium Chloride + ethylene glycol DES were measured by the gas-liquid chromatography (GLC) method at four temperatures in the range from (313.15–343.15) K. Experimental measurements were undertaken with an overall uncertainty of ±5.4%. The effect of the structure of the solutes on γ 13 ∞ was also investigated. For all investigated solutes, Gibbs helmholtz relationship was utilised to derive partial molar excess enthalpy values at infinite dilution ( Δ H i E , ( ∞ ) ) from experimental limiting activity coefficient data. From selectivity ( S i j ∞ ) and capacity ( k j ∞ ) values at infinte dilution, it was concluded that the investigated DES has the potential to replace a number of industrial solvents for the separation of various industrial mixtures.

Raoul Zana - One of the best experts on this subject based on the ideXlab platform.

  • Effect of the Nature of the Counterion on the Properties of Anionic Surfactants. 1. Cmc, Ionization Degree at the Cmc and Aggregation Number of Micelles of Sodium, Cesium,
    2016
    Co-Authors: Tetrabutylammonium Dodecyl Sulfates, Mohamed Benrraou, Barney L. Bales, Raoul Zana
    Abstract:

    ion-exchange. The critical micellization concentration in the absence of added salt (cmc) has been determined at 10, 25, and 40 °C using the electrical conductivity method. The cmc was found to decrease in the sequence CsDS> TMADS> TEADS> TPADS> TBADS. The value of the cmc depends very little on temperature, going through a shallow minimum around 25 °C for most surfactants investigated. The micelle aggregation numbers have been determined using the time-resolved fluorescence quenching method, with the pyrene/ dodecylpyridinium Chloride as fluorescent probe/quencher pair, at various surfactant concentrations and, in the case of TMADS, in the presence of Tetramethylammonium Chloride. The micelle ionization degree R0 at the cmc has been determined from the electrical conductivity data and the values of the aggregation number extrapolated to the cmc. The micelle ionization degree was the largest for SDS (sodium dodecyl sulfate) and the smallest for TBADS. The micelle micropolarity, as determined by the pyrene polarity ratio I1/I3, was a maximum for TEADS. The micelle microviscosity, investigated using the fluorescent probe 1,3-dipyrenyl-propane, increased in the sequence CsDS < SDS < TMADS < TEADS TBADS TPADS. At 10 °C, the micelle aggregation number decreases as the counterion radius increases, contrary to what was expected on the basis of the cmc values. At 40 °C, the sequence of the aggregation numbers is almost that expected from the cmc values. An intermediate result was obtained at 25 °C. The micelle aggregation number increase

  • effect of the nature of the counterion on the properties of anionic surfactants 1 cmc ionization degree at the cmc and aggregation number of micelles of sodium cesium Tetramethylammonium tetraethylammonium tetrapropylammonium and tetrabutylammonium d
    Journal of Physical Chemistry B, 2003
    Co-Authors: Mohamed Benrraou, And Barney L Bales, Raoul Zana
    Abstract:

    The surfactants cesium, Tetramethylammonium, tetraethylammonium, tetrapropylammonium and tetrabutylammonium dodecyl sulfates (CsDS, TMADS, TEADS, TPADS, and TBADS) have been synthesized by ion-exchange. The critical micellization concentration in the absence of added salt (cmc) has been determined at 10, 25, and 40 °C using the electrical conductivity method. The cmc was found to decrease in the sequence CsDS > TMADS > TEADS > TPADS > TBADS. The value of the cmc depends very little on temperature, going through a shallow minimum around 25 °C for most surfactants investigated. The micelle aggregation numbers have been determined using the time-resolved fluorescence quenching method, with the pyrene/dodecylpyridinium Chloride as fluorescent probe/quencher pair, at various surfactant concentrations and, in the case of TMADS, in the presence of Tetramethylammonium Chloride. The micelle ionization degree α0 at the cmc has been determined from the electrical conductivity data and the values of the aggregation n...

Maaike C. Kroon - One of the best experts on this subject based on the ideXlab platform.

  • Experimental determination of the LLE data of systems consisting of {hexane + benzene + deep eutectic solvent} and prediction using the Conductor-like Screening Model for Real Solvents
    Journal of Chemical Thermodynamics, 2017
    Co-Authors: Nerea R. Rodriguez, Daniëlle Scheepers, Thomas Gerlach, Maaike C. Kroon, Irina Smirnova
    Abstract:

    Recently, deep eutectic solvents (DESs) have proven to be excellent extracting agents in the separation of aromatic components from their mixtures with aliphatic compounds. The tunable properties of the DESs allow to tailor-make optimal solvents for this application. In this work type III DESs, based on Chloride quaternary ammonium salts (Tetramethylammonium Chloride, tetraethylammonium Chloride, tetrabutylammonium and tetrahexylammonium Chloride) as hydrogen bond acceptor molecules and polyols (ethylene glycol and glycerol) as hydrogen bond donor molecules were used. The liquid-liquid equilibrium (LLE) data of the system {hexane + benzene + DES} was measured at room temperature and atmospheric pressure. The solute distribution ratio and the selectivities were calculated and compared. The highest solute distribution ratios were obtained for salts with long alkyl chain length as hydrogen bond acceptor molecules and for ethylene glycol as hydrogen bond donor molecules. COSMO-RS was used for the prediction of the LLE data of the studied systems. It was found that both the LLE data and the solute distribution ratio of the ternary systems containing DESs can be qualitatively well predicted using this model. Moreover, the LLE data was quantitatively predicted within a root mean square error of 10 wt% without the need of any experimental data. This implies that COSMO-RS is an effective screening tool for the optimization of the separation process of aromatic components from {aliphatic + aromatic} mixtures using DESs as extracting agents.

  • Glycerol-Based Deep Eutectic Solvents as Extractants for the Separation of MEK and Ethanol via Liquid–Liquid Extraction
    2016
    Co-Authors: Nerea R. Rodriguez, Jordi Ferre Guell, Maaike C. Kroon
    Abstract:

    Four different glycerol-based deep eutectic solvents (DESs) were tested as extracting agents for the separation of the azeotropic mixture {methyl ethyl ketone + ethanol} via liquid–liquid extraction. The selected DESs for this work were: glycerol/choline Chloride with molar ratios (4:1) and (2:1), and glycerol/Tetramethylammonium Chloride with molar ratios (4:1) and (2:1). The selected DESs have been characterized by measuring the density and the viscosity at different temperatures. The liquid–liquid equilibria data of the ternary systems {methyl ethyl ketone + ethanol + DES} were experimentally determined at T/K = 298.15 and atmospheric pressure. The extraction efficiencies of the selected DESs were analyzed by determining the solute distribution coefficients and the selectivity values, which were calculated from the experimental results. The extraction performance of the DESs was compared to the extraction data of pure glycerol. The integrity of the DESs after recovery was also studied. Finally, the experimental LLE data were regressed using the nonrandom two liquid (NRTL) model. It was found that the addition of a hydrogen bond acceptor to glycerol, and therefore, the formation of a deep eutectic solvent, improves the extraction efficiency of this mixture via liquid–liquid extraction

  • PC-SAFT Modeling of CO2 Solubilities in Deep Eutectic Solvents
    2016
    Co-Authors: Lawien F. Zubeir, Christoph Held, Gabriele Sadowski, Maaike C. Kroon
    Abstract:

    Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT), a physically based model that accounts for different molecular interactions explicitly, was applied to describe for the first time the phase behavior of deep eutectic solvents (DESs) with CO2 at temperatures from 298.15 to 318.15 K and pressures up to 2 MPa. DESs are mixtures of two solid compounds, a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA), which form liquids upon mixing with melting points far below that of the individual compounds. In this work, the HBD is lactic acid and the HBAs are Tetramethylammonium Chloride, tetraethylammonium Chloride, and tetrabutylammonium Chloride. Two different modeling strategies were considered for the PC-SAFT modeling. In the first strategy, the so-called pseudo-pure component approach, a DES was considered as a pseudo-pure compound, and its pure-component parameters were obtained by fitting to pure DES density data. In the second strategy, the so-called individual-component approach, a DES was considered to consist of two individual components (HBA and HBD), and the pure-component parameters of the HBA and HBD were obtained by fitting to the density of aqueous solutions containing only the individual compounds of the DES. In order to model vapor–liquid equilibria (VLE) of DES + CO2 systems, binary interaction parameters were adjusted to experimental data from the literature and to new data measured in this work. It was concluded that the individual-component strategy allows quantitative prediction of the phase behavior of DES + CO2 systems containing those HBD:HBA molar ratios that were not used for kij fitting. In contrast, applying the pseudo-pure component strategy required DES-composition specific kij parameters

  • the low transition temperature mixture lactic acid Tetramethylammonium Chloride 2 1 as novel co2 capture solvent
    2014
    Co-Authors: L Lawien F Zubeir, Mhm Mark Lacroix, Maaike C. Kroon
    Abstract:

    Oral SCF5 : keywords : Low transition temperature mixtures (LTTMs), deep eutectic solvents (DESs), CO2 solubility

  • Low Transition Temperature Mixtures as Innovative and Sustainable CO2 Capture Solvents
    2014
    Co-Authors: Lawien F. Zubeir, Mark H. M. Lacroix, Maaike C. Kroon
    Abstract:

    The potential of three newly discovered low transition temperature mixtures (LTTMs) is explored as sustainable substituents for the traditional carbon dioxide (CO2) absorbents. LTTMs are mixtures of two solid compounds, a hydrogen bond donor (HBD) and a hydrogen bond acceptor (HBA), which form liquids upon mixing with melting points far below those of the individual compounds. In this work the HBD is lactic acid and the HBAs are Tetramethylammonium Chloride, tetraethylammonium Chloride, and tetrabutylammonium Chloride. These compounds were found to form LTTMs for the first time at molar ratios of HBD:HBA = 2:1. First, the LTTMs were characterized by determining the thermal operating window (e.g., decomposition temperature and glass transition temperature) and the physical properties (e.g., density and viscosity). Thereafter, the phase behavior of CO2 with the LTTMs has been measured using a gravimetric magnetic suspension balance operating in the static mode at 308 and 318 K and pressures up to 2 MPa. The CO2 solubility increased with increasing chain length, increasing pressure, and decreasing temperature. The Peng–Robinson equation of state was applied to correlate the phase equilibria. From the solubility data, thermodynamic parameters were determined (e.g., Henry’s law coefficient and enthalpy of absorption). The heat of absorption was found to be similar to that in conventional physical solvents (−11.21 to −14.87 kJ·mol–1). Furthermore, the kinetics in terms of the diffusion coefficient of CO2 in all LTTMs were determined (10–11–10–10 m2·s–1). Even though the CO2 solubilities in the studied LTTMs were found to be slightly lower than those in thoroughly studied conventional physical solvents, LTTMs are a promising new class of absorbents due to their low cost, their environmentally friendly character, and their easy tunability, allowing further optimization for carbon capture