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1.
Study on cloud points of Triton X-100-cationic gemini surfactants mixtures: A spectroscopic approach
Halide Akbaş Mesut Boz Çiğdem Batıgöç 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(2):671-677
This study investigates the effects of various cationic surfactants on the cloud point (CP) of the nonionic surfactant Triton X-100 (TX-100) in aqueous solutions. Instead of visual observation, a spectrophotometer was used for measurement of the cloud point temperatures. The values of CPs for Triton X-100 can be measured directly because TX-100 has an average number of oxyethylene units per molecule of p ≈ 9.5 and a CP = 66.0 °C. Quaternary ammonium dimeric surfactants (m-s-m, m = 10, 12, and 16, and s = 2, 6, and 10) were synthesized and used. The melting temperature TM and the Krafft temperature TK were measured for 1 wt% aqueous solutions of these synthesized surfactants. The melting temperature of the solid gemini surfactants increased with the carbon number of the alkyl chain. The results showed that additions of the gemini surfactants (which are infinitely miscible with water) to Triton X-100 increased the cloud point of the TX-100 solutions. All salts tested in these studies had a large effect on the CPs of nonionic surfactants due to their effect on water structure and their hydrophilicity. The effect of the alkyl chain length of the gemini surfactant on the CP of Triton X-100 is therefore more important than the spacer chain length. 相似文献
2.
Francisco J. Deive Miguel A. Rivas Ana Rodríguez 《The Journal of chemical thermodynamics》2011,43(8):1153-1158
Several methylsulfate and chloride anion-based ionic liquids, such as 1-alkyl-3-methyl imidazolium methyl sulfate, CnMIM CH3SO4 (n = 1, 2, and 4), 1-benzyl-3-methyl imidazolium methyl sulfate, BzMIM CH3SO4, 1-benzyl, or hexyl-3-methyl imidazolium chloride, XMIM Cl (X = Bz and Hx), and methylpyridinium methylsulfate, Mpy CH3SO4, with sodium carbonate, Na2CO3, as phase forming salt, have been investigated and discussed for their potential use in separations based on aqueous two-phase systems (ATPS). Phase diagrams have been experimentally ascertained at T = 298.15 K, and Merchuck equation and a variation of this model have been used for correlating the binodal data. The alkyl chain length in the cation and the type of anion and cation have been explored and discussed due to their decisive influence in the ATPS behavior. The consistence of tie-line data was ascertained by applying the Othmer–Tobias and Bancroft equations. 相似文献
3.
During the last years, the extraction of biomolecules and chemicals by means of Aqueous Biphasic Systems (ABS) has triggered a renewed interest, making it necessary to characterize fully the solubility data of this kind of system. In this study, two surfactants belonging to Triton X series (Triton X-100 and Triton X-102) are proposed as candidates to form ABS, by adding different potassium-based salts (K3PO4, K2HPO4, K2CO3, K2S2O3 and K2SO3) at T = 298.15 K. Several equations were used to fit the solubility data which were previously obtained by means of the cloud point method. The different phase forming capacities were analyzed in the light of the Hofmeister series, the Effective Excluded Volume (EEV) theory and the molar Gibbs free energy of hydration (ΔhydG). The Othmer–Tobias equation was proposed to correlate the tie-line data. 相似文献
4.
During recent last years, outstanding properties of ionic liquids such as low melting point, large liquid range and negligible volatility have turned them into possible volatile organic solvents replacers to break alcohol-alkane azeotropic mixtures. On this basis, two ionic liquids, butyltrimethylammoniumbis(trifluoromethylsulfonyl)imide, [BTMA][NTf2], and tributylmethylammoniumbis(trifluoromethylsulfonyl)imide, [TBMA][NTf2], were studied through ternary liquid+liquid equilibrium (LLE) of {alkane(1) + alcohol (2) + IL(3)} at T = 298.15 K and atmospheric pressure in order to consider the effect of ionic liquid cation alkyl chain length on the extraction process.The ILs capability as azeotrope breakers was determined by the calculation of parameters such as solute distribution ratio, β, and selectivity, S and this capability was compared with other bis (trifluoromethylsulfonyl)imide based ionic liquids from literature. The consistency of tie-line data was ascertained by applying the Othmer–Tobias and Hand equations. Finally, the experimental LLE were correlated by the Non Random Two Liquid (NRTL) thermodynamic model. 相似文献
5.
《The Journal of chemical thermodynamics》2012,44(12):1886-1892
Osmotic coefficients of the binary solutions of two room-temperature ionic liquids (1-butyl-3-methylimidazolium chloride and bromide) in methanol and ethanol have been measured at T = 298.15 K by the isopiestic method. The experimental osmotic coefficient data have been correlated using a forth-order polynomial in terms of (molality)0.5, with both, ion interaction model of Pitzer and electrolyte non-random two liquid (e-NRTL) model of Chen. The values of vapor pressures of above-mentioned solutions have been calculated from the osmotic coefficients. The model parameters fitted to the experimental osmotic coefficients have been used for prediction of the mean ionic activity coefficients of those ionic liquids in methanol and ethanol. 相似文献
6.
Xiao-Ming Peng Yu-Feng Hu Chuan-Wei Jin 《The Journal of chemical thermodynamics》2011,43(8):1174-1177
The solubilities of ionic liquids in the ternary systems (ionic liquid + H2O + inorganic salt) were reported at 298.15 K and atmospheric pressure. The examined ionic liquids are [C4mim][PF6] (1-n-butyl-3-methylimidazolium hexafluorophosphate), [C8mim][PF6] (1-n-octyl-3-methylimidazolium hexafluorophosphate), and [C8mim][BF4] (1-n-octyl-3-methylimidazolium tetrafluoroborate). The examined inorganic salts are the chloride-based salts (sodium chloride, lithium chloride, potassium chloride, and magnesium chloride) and the sodium-based salts (sodium thiocyanate, sodium nitrate, sodium trifluoroacetate, sodium bromide, sodium iodide, sodium perchlorate, sodium acetate, sodium hydroxide, sodium dihydrogen phosphate, sodium phosphate, sodium tetrafluoroborate, sodium sulfate, and sodium carbonate). The effects of the cations and the anions of the ionic liquids and of the inorganic salts on the solubility of the ionic liquids in the ternary solutions were systematically compared and discussed. 相似文献
7.
(Liquid + liquid) equilibria for {1-benzyl-3-methylimidazolium chloride ([BzMIM]Cl) or 1-hexyl-3-methylimidazolium chloride ([HMIM]Cl) + inorganic salts (potassium phosphate K3PO4, potassium carbonate K2CO3, or dipotassium hydrogen phosphate K2HPO4) + H2O} aqueous biphasic systems (ABSs) are presented at T = 298.15 K. An empirical equation was used to correlate the binodal data. The experimental tie lines were appropriately correlated by the Othmer–Tobias and Brancroft empirical equations. The influence of the selected inorganic salts in the phase segregation was investigated by means the calculated effective excluded volume (EEV) and Setschenow-type equation. The salting-out ability of salts was also evaluated in terms of the Gibbs energy of hydration of salt (ΔGhyd) and assessed with EEV values. 相似文献
8.
The thermophysical properties of hydroxyl ammonium ionic liquids: density ρ, T = (293.15 to 363.15) K; dynamic viscosity η, T = (298.2 to 348.2) K; and refractive indices nD, T = (293.15 to 333.15) K have been measured. The coefficients of thermal expansion α, values were calculated from the experimental density results using an empirical correlation for T = (293.15 to 363.15) K. The variation of volume expansion of ionic liquids studied was found to be independent of temperature within the range covered in the present work. The thermal decomposition temperature ‘Td’ for all the six hydroxyl ammonium ionic liquids is also investigated using thermogravimetric analyzer (TGA). 相似文献
9.
Suitability of a pyridinium ionic liquid as a solvent in desulfurization has been analyzed. (Liquid + liquid) equilibria for ternary systems composed by 1-hexyl-3,5-dimethyl pyridinium {bis[trifluoromethylsulfonyl]imide, thiophene, and three hydrocarbons representative of fuel (n-heptane, 2,2,4 trimethylpentane, and toluene) have been determined at T = 298.15 K and atmospheric pressure. High solubility of thiophene in the ionic liquid and also of toluene have been found, being this solvent practically immiscible with 2,2,4 trimethylpentane and heptane. Equilibrium data of these systems have been well correlated with UNIQUAC equations finding the highest deviations for the ternary system involving toluene. NRTL model drove to worse results being considered as not suitable model to correlate the experimental results. 相似文献
10.
The ternary (liquid + liquid) equilibrium (LLE) data for mixtures of dodecane (C12H26) and ethanol with ionic liquids 1,3-dimethylimidazolium methylsulfate [Mmim][MeSO4], 1-ethyl-3-methylimidazolium methylsulfate, [Emim][MeSO4] and 1-butyl-3-methylimidazolium methylsulfate, [Bmim][MeSO4], were studied at T = 298.15 K and 0.101 MPa. The selectivity and solute distribution coefficient ratios determined from the data were used to examine the possibility of using these ionic liquids for extraction of ethanol from dodecane. The temperature dependency was investigated by measuring the LLE data for {dodecane + ethanol + [Mmim][MeSO4]} at T = 313.15 K and 0.101 MPa. The Othmer–Tobias and Hand equations were used to test the consistency of the tie-line data. The tie-line data were correlated with the Non-Random Two Liquid (NRTL) equation which provided a good model and representation for the experimental results. 相似文献
11.
Water activity measurements by the isopiestic method have been carried out on the aqueous ternary system of {l-serine + 1-(2-carboxyethyl)-3-methylimidazolium chloride[HOOCEMIM][Cl]} ionic liquid and the aqueous binary system of IL at T = 298.15 K and atmospheric pressure. The data obtained were used to calculate the vapor pressure and osmotic coefficient of solution as a function of concentration. The experimental results for the activity of water were accurately correlated with segment-based local composition models of modified NRTL and UNIQUAC. The fitting quality of the above models has been favorably compared with the NRTL and Wilson models. From these data, the corresponding activity coefficients have been calculated. For the same system, the solubility of the l-serine at various [HOOCEMIM][Cl] ionic liquid concentrations was measured at T = 298.15 K using the gravimetric method. A chemical model was employed to describe the dissociation equilibria of all amino acid species with hydrogen ions in water. Moreover, for l-serine, the chemical model indicated that the formation of cations is insignificant in the [HOOCEMIM][Cl] solution. Also the above local composition models were used to predict the solubility of l-serine in aqueous IL solutions. To provide information regarding (solute + solute) interactions, transfer Gibbs free energies (ΔGtr) of amino acid from water to aqueous IL solutions have been determined. 相似文献
12.
The densities of tetraphenylphosphonium bromide, sodium tetraphenylborate, lithium perchlorate, sodium perchlorate and lithium bromide in γ-butyrolactone at (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15) K and speed of sound at 298.15 K have been measured. From these data apparent molar volumes VΦ at (288.15, 293.15, 298.15, 303.15, 308.15 and 313.15) K and the apparent molar isentropic compressibility KS,Φ, at T = 298.15 K of the salts have been determined. The apparent molar volumes and the apparent molar isentropic compressibilities were fitted to the Redlich, Rosenfeld and Mayer equation as well as to the Pitzer and Masson equations yielding infinite dilution data. The obtained limiting values have been used to estimate the ionic data of the standard partial molar volume and the standard partial isentropic compressibility in γ-butyrolactone solutions. 相似文献
13.
Experimental air–liquid interfacial tension data and density data are presented for three 1-Cn-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphates (FAP), [CnMIM][(C2F5)3PF3], with n = 2, 4, and 6, measured at atmospheric pressure in the temperature range from 267 K to 360 K using the Krűss K100MK2 tensiometer. The accuracy of the surface tension measurements was checked by employing the Wilhelmy plate and the du Noüy ring methods in parallel. The combined standard uncertainty associated with the Wilhelmy plate method is estimated to be ±0.1 mN · m−1. The density data were obtained using buoyancy method with an estimated standard uncertainty less then ±0.4 kg · m−3 (3 · 10−4ϱ). The chloride anions decrease the density of the tris(pentafluoroethyl)trifluorophosphates of interest up to six times more effectively than they decrease the density of the imidazolium based tetrafluoroborates. A QSPR analysis of the surface tension of imidazolium based ionic liquids with BF4, TFA, DCA, FAP, NTf2, and PF6 anions indicates, that the FAP ionic liquids fit well into the analyzed group of imidazolium based ionic liquids while those having hexafluorophosphate anion show anomalously high deviations of the experimental surface tension from the values predicted by the QSPR model. 相似文献
14.
《The Journal of chemical thermodynamics》2007,39(8):1206-1216
Densities of amino acids in aqueous and in aqueous electrolyte solutions have been measured by a high precision vibrating tube digital densitometer at T = 298.15 K under atmospheric pressure. The investigated systems contained amino acids of zwitterionic glycine peptides: glycine (Gly), diglycine (Gly2), triglycine (Gly3), and tetraglycine (Gly4) and cyclic glycylglycine (c(GG)) with electrolytes of potassium chloride (KCl), potassium bromide (KBr) and potassium acetate (KAc). In this series of measurements, the aqueous samples were prepared with various concentrations of the amino acids, up to saturated conditions, and over salt concentrations from 1 to 4 M. The density increments resulting from the addition of the different model compounds of amino acids and the ionic salts were investigated, respectively. An empirical linear combination equation with an augmented term to account the interactions between amino acid and ionic salt was used to quantitatively correlate the experimental densities over the entire concentration ranges. 相似文献
15.
《Comptes Rendus de l''Academie des Sciences Series IIB Mechanics Physics Astronomy》2000,3(5):353-358
The adsorption isotherms of Triton X-100 for air/water–orthophosphoric acid interfaces were determined by the stripping method. The surface chemical parameters, Γmax, F and ΔG°A, and the aggregation ones, CMC and the ΔGM, are determined in different H2O/H3PO4 mixtures. For concentrations higher than 4 M, the values of the CMC, ΔGM, Γmax and ΔG°A increase with increasing acid concentrations due to the occurring changes in the medium structure. ©2000 Académie des sciences / Éditions scientifiques et médicales Elsevier SASsurface tension / non-ionic surfactant / micellization / orthophosphoric acid 相似文献
16.
Ensieh Ghasemian Mojgan Najafi Amir Abbas Rafati Zahra Felegari 《The Journal of chemical thermodynamics》2010,42(8):962-966
Surface and bulk properties of 1-hexyl-3-methylimidazolium chloride [C6mim][Cl] as an ionic liquid (IL) have been investigated by surface tension and electrical conductivity techniques at various temperatures. Results reveal that the ionic liquid behaves as surfactant-like and aggregates in aqueous solution. Critical aggregation concentration (cac) values obtained by conductivity and surface tension measurements are in good agreement with values found in the literature. A series of important and useful adsorption parameters including cac, surface excess concentration (Γ), and minimum surface area per molecule (Amin) at the air + water interface were estimated from surface tension in the presence and absence of different electrolytes. Obtained data show that the surface tension as well as the cac of [C6mim][Cl] is reduced by electrolytes. Also, values of surface excess concentration (Γ) show that the IL ions in the presence of electrolyte have much larger affinity to adsorption at the surface and this affinity increased in aqueous electrolyte solution in the order of I? > Br? > Cl? for counter ion of salts that was explained in terms of a larger repulsion of chloride anions from interface to the bromide and iodide anion as well as difference in their excess polarizability. 相似文献
17.
The effect of six different high charge density sodium inorganic salts, such as Na2CO3, Na2SO4, Na2S2O3, Na2SO3, Na2HPO4 and NaCH3COO, in aqueous solutions of two anionic surfactants Tween 20 and Triton X-102 was investigated at T = 298.15 K and atmospheric pressure. The results were qualitatively analyzed in the light of the Hofmeister series. Also, a quantitative thermodynamic analysis in terms of molar Gibbs free energy of hydration (ΔhydG) was carried out. The Merchuck equation was used to correlate the solubility curves and the tie line data were modelled by applying the Othmer–Tobias and Bancroft equations. 相似文献
18.
Emilio J. González Noelia Calvar Begoña González Ángeles Domínguez 《The Journal of chemical thermodynamics》2010,42(6):752-757
In this paper, the separation of toluene from aliphatic hydrocarbons (heptane, or octane, or nonane) was analyzed by solvent extraction with 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid, [EMpy][ESO4]. Liquid?liquid equilibrium (LLE) data for the ternary systems {heptane (1) + toluene (2) + [EMpy][ESO4] (3)}, {octane (1) + toluene (2) + [EMpy][ESO4] (3)}, and {nonane (1) + toluene (2) + [EMpy][ESO4] (3)} were obtained by measurements at T = 298.15 K and atmospheric pressure. The selectivity, % removal of aromatic, and solute distribution ratio, obtained from experimental equilibrium results, were used to determine the ability of [EMpy][ESO4] as a solvent. The degree of consistency of the experimental LLE values was ascertained using the Othmer–Tobias and Hand equations. The experimental results for the ternary systems were correlated with the NRTL model. Finally, the results obtained were compared with other ionic liquids and other solvents. 相似文献
19.
Rahmat Sadeghi Hemayat Shekaari Rahim Hosseini 《The Journal of chemical thermodynamics》2009,41(2):273-289
The alkyl chain length of 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = propyl (C3), hexyl (C6), heptyl (C7), and octyl (C8)) was varied to prepare a series of room-temperature ionic liquids (RTILs), and experimental measurements of density and speed of sound at different temperatures ranging from (288.15 to 308.15) K for their aqueous and methanolic solutions in the dilute concentration region (0.01 to 0.30) mol · kg?1 were taken. The values of the compressibilities, expansivity and apparent molar properties for [Cnmim][Br] in aqueous and methanolic solutions were determined at the investigated temperatures. The obtained apparent molar volumes and apparent molar isentropic compressibilities were fitted to the Redlich–Mayer and the Pitzer’s equations from which the corresponding infinite dilution molar properties were obtained. The values of the infinite dilution molar properties were used to obtain some information about solute–solvent and solute–solute interactions. The thermodynamic properties of investigated ionic liquids in aqueous solutions have been compared with those in methanolic solutions. Also, the comparison between thermodynamic properties of investigated solutions and those of electrolyte solutions, polymer solutions, cationic surfactant solutions and tetraalkylammonium salt solutions have been made. 相似文献
20.
Zhiyong Li Yuanchao Pei Li Liu Jianji Wang 《The Journal of chemical thermodynamics》2010,42(7):932-937
In the present work, (liquid + liquid) equilibrium data have been determined experimentally for aqueous two-phase systems formed by the imidazolium ionic liquids of [Cnmim][CH3COO] (n = 4, 6, 8) and inorganic salts of K3PO4, K2HPO4, and K2CO3 at T = 298.15 K. Combined with available data in the literature, the effect of alkyl chain length of cations, type of anions of the ionic liquids, and nature of the inorganic salts were examined on the binodal curves of the systems. Then the binodal curves were fitted to a four-parameter empirical equation, and the tie-lines were described by the Othmer–Tobias and Bancroft equations. In addition, the extraction capacity of the {[Cnmim][CH3COO] (n = 4, 6, 8) + K3PO4} aqueous two-phase systems was evaluated through their application to the extraction of l-tryptophan. The high extraction efficiency suggests that these aqueous two-phase systems are feasible to be used in the extraction and separation process. 相似文献