Pseudoternary System Research Articles

Liquid–liquid equilibria of aromatics removal from middle distillate using NMP

We investigated the removal of aromatics from a typical Kuwait middle distillate using liquid–liquid extraction. A multicomponent system; dodecane + hexadecane + 1,3,5-trimethyl benzene (mesitylene) + butylbenzene; was used to represent the middle distillate mixture. N-methyl-2-pyrrolidone (NMP) was used as a solvent. The liquid–liquid equilibria (LLE) of the mixture was studied over a temperature range of 293–323 K and at different solvent to feed ratios (1.35–1.97). The selectivity and distribution coefficient of the solvent were correlated successfully using the universal quasi-chemical (UNIQUAC) model for the pseudo-ternary system (paraffins (1) + aromatics (2) + NMP (3)) at the studied temperature range. The UNIQUAC model fit the experimental data with an average percentage root mean square deviation (rmds) of 0.2980%.

Phase equilibria in ternary reciprocal systems based on IV–VI compounds

Using the experimental data obtained in this study, literature data, and a unified thermodynamic model, we have calculated the T − x − y phase diagrams of all the pseudoternary reciprocal systems formed by the Group 14 metal chalcogenides: Sn, Pb ‖ S, Se; Sn, Pb ‖ S, Te; and Sn, Pb ‖ Se, Te.

Polyampholyte-modified ionic microemulsions

This paper is focused on the influence of added polyampholyte, namely poly(N,N′-diallyl-N,N′-dimethyl-alt-maleamic carboxylate) on the inverse micellar phase range of the pseudo-ternary system consisting of toluene–pentanol (1:1)/SDS/water in dependence on the pH value and the temperature. Investigations on phase behavior have revealed that a greater extension in direction to the water-rich corner can be found at pH 4 compared to pH 9. In order to understand changes in the microstructure, polymer–surfactant interactions in dependence on pH have been examined by means of diffusion-ordered spectroscopy, differential scanning calorimetry, as well as conductivity measurements. The results have proven that the present microemulsion consists of water-in-oil droplets, with the polyampholyte located more in the inner core of the water droplets at pH 9 rather than at the interphase of the surfactant film at pH 4.

The lanthanum(III) molybdate(VI) La4Mo7O27

Crystals of the ortho­rhom­bic phase La4Mo7O27 (lanthanum molybdenum oxide) were obtained from a non-stoichiometric melt in the pseudo-ternary system La2O3–MoO3–B2O3. In the crystal structure, distorted square-anti­prismatic [LaO8] and monocapped square-anti­prismatic [LaO9] polyhedra are connected via common edges and faces into chains along [010]. These chains are arranged in layers that alternate with layers of [MoO4] and [MoO5] polyhedra parallel to (001). In the molybdate layers, a distorted [MoO5] trigonal bipyramid is axially connected to two [MoO4] tetra­hedra, forming a [Mo3O11] unit.

Liquid−Liquid Equilibrium Data for Fatty Systems Containing Refined Rice Bran Oil, Oleic Acid, Anhydrous Ethanol, and Hexane

The objective of this work was to determine liquid−liquid equilibrium data for fatty systems of interest in the extraction/refining process of vegetable oils and in the biodiesel production. The following systems were investigated: refined rice bran oil + anhydrous ethanol + hexane at (298.15 ± 0.2) K and (313.15 ± 0.2) K and refined rice bran oil + commercial oleic acid + anhydrous ethanol + hexane at (298.15 ± 0.2) K with mass fractions of (5.08, 7.98, 10.65, and 15.09) % of fatty acid in oil. The instrumental technique of near-infrared spectroscopy allied to multivariate calibration (in this work, termed “NIR method”) was used for quantification of the phase compositions. For the pseudoternary system, the relative deviations for global mass balance were (0.10 and 0.11) % for the temperature of (298.15 and 313.15) K, respectively. For the pseudoquaternary systems, the relative deviations for global mass balance varied in the range from (0.15 to 0.31) %. The experimental data were correlated using the NRTL model with overall deviations lower than 1.15 %. We can conclude that the NIR method is highly accurate, and the low deviations obtained indicate the good quality of the equilibrium data.

Polymer-Modified Bicontinuous Microemulsions Used as a Template for the Formation of Nanorods

This article is focused on the characterization of the poly(ethylene glycol) (PEG)-induced bicontinuous microemulsion of the pseudo-ternary system sodium dodecylsulfate (SDS)/xylene-pentanol/water by means of differential scanning calorimetry, rheology, and conductometry. The influence of the polymer concentration (cp) and the molecular weight (Mw) on the microstructure of the microemulsion was investigated using Cryo scanning electron microscopy. It was found that an increase of cp influences the structure of the sponge-like phase significantly. These polymer-modified microemulsions can be used as a template phase for the formation of BaSO4 nanorods, where individual nanoparticles (5 nm in size) are ordered along the polymer backbone.

Synthesis of glasses in the system Na2O – B2O3 – SiO2 for coatings protecting bronze during smelting

A system of requirements for unfired process glass coatings for protecting bronze during smelting is formulated and the properties of the coatings are determined. DTA analysis shows the most critical service temperature interval for the new coatings. The initial system Na 2 - B 2 O 3 - SiO 2 and the initial materials for synthesizing glass coatings on it are chosen. The method of mathematical planning of experiments is used to optimize the composition of the glass flux in the pseudoternary system silicate-block - cullet - borax.

Components Screening and Influence of Surfactant and Cosurfactant on Nanoemulsion Formation

Proper selection of oils, surfactants and cosurfactants along with their optimum concentration is crucial to obtain stable, mild and clinically acceptable nanoemulsions. The focus of the present study was, therefore, to provide an efficient screening approach for the excipients selection for the optimum nanoemulsion formulation development. The oils studied included Lauroglycol 90, Capryol 90, olive oil, jojoba oil, oleic acid and Labrafil M1944. The drug solubility in the oil was taken as the criterion for oil selection. Labrasol, Cremophor EL, Tween 60 and Tween 80 were the surfactants evaluated for determining the solubilizing capacity for the oil. Among them Cremophor EL was found to be an efficient emulsifier for the oil phase. The effect of different cosurfactants such as ethanol, isopropyl alcohol, butanol, propylene glycol, PEG 400 and Carbitol on the phase behaviour of the pseudoternary system Capryol 90/Cremophor EL/cosurfactant/water was investigated. Nanoemulsion region obtained was used as an assessment criterion to evaluate the cosurfactants. The effect of Cremophor EL/carbitol mass ratio on the nanoemulsion formation was also studied by varying the ratio from 3:1 to 1:3 for the further optimization of the system. The highest nanoemulsion region was obtained at Cremophor EL: Carbitol in the mass ratio of 1:1. Formulations were selected from the phase diagram at this mass ratio at a fixed concentration of surfactant mixture (i.e. 45% wt/wt) with increasing concentration of oil (5, 10, 15, 20% wt/wt) and subjected to thermodynamic stability tests. The optimized formulations were characterized for particle size, viscosity, pH and refractive index measurements. The droplet size of all the selected formulations was found to be less than 100 nm. The formulations were thermodynamically stable and can be effectively used for the drug delivery applications. Keywords: Nanoemulsions, solubility, oil, surfactant, cosurfactant, pseudoternary phase diagram

Organization of Amphiphiles, Part IX: Effect of Molecular Structure of Cosurfactants and Oils on the Phase Behavior of Tween-80: Alkanol-Oil-Water Systems

In Tween-80:alkanol-oil-water pseudoternary system the area of the subregions are found to depend upon the molecular volume and structural hierarchy of oil and cosurfactants used. The threshold weight fraction of 0.35 for cosurfactant in emulsifier, required to get maximum area of bicontinuous region is attributed to difference in solubility of the emulsifier in oil and water. The measurement of different physicochemical parameters conforms to the phase transition from w/o to o/w through bicontinuous region. The phase behavior of Tween-80:alkanol-oil-water systems have been studied at 30°C by varying the composition of the emulsifier. The areas of both isotropic and anisotropic regions are found to depend on the type of alcohols and oil used. The results have been attributed to the constraints in packing at the interface due to difference in molar volume as well as structural hierarchy in three-dimensional space. The percolation transition is evident from conductivity studies. The determination of area of the sub-regions as a function of surfactant:cosurfactant ratio reveals the existence of a maximum value for bicontinuous region at 0.35 weight fraction of cosurfactant in the emulsifier. This threshold weight fraction has been attributed to the difference in limiting solubility of emulsifier in water and oil. The phase inversion leading to drastic structural changes has been suggested from physicochemical properties measurements.

Estimation of oxygen potential for U–Pu–O mixed oxide fuel

A thermochemical analysis of the estimation of oxygen potential for mixed oxide fuel is presented. The MOX fuel is treated as a pseudo-quaternary solid solution of UO 2–U c O d –PuO 2–Pu a O b with b = 1.5 a and d = 2.25 c. The hypo-stoichiometric fuel is viewed as UO 2–(1/ a)Pu a O b –PuO 2 pseudo-ternary system and the hyper-stoichiometric fuel is viewed as UO 2–(1/ c)U c O d –PuO 2 pseudo-ternary system and the graphical representation is visualized as a ‘diamond plot’. The oxygen potential for MOX is determined either by PuO 2–Pu a O b equilibria or by the UO 2–U cO d equilibria subject to the constraint that the oxygen potential is equal both in Pu–O subsystem and in U–O subsystem. The choice of stoichiometric parameters a and c affects the relative contribution of configurational entropy to the oxygen potential which determines the shape of the ‘S’-type curve near exact stoichiometry. From the analysis of literature data, a = 2 and c = 8 was derived at for the ‘diamond plot’ model. Oxygen potentials for MOX fuel with 21, 28% and 44% plutonia was estimated using the ‘diamond plot’ model. A simplified nomograph for the oxygen potential of MOX is presented.

Advantages of Simultaneous Substitution of Co in Li[Ni[sub 1∕3]Mn[sub 1∕3]Co[sub 1∕3]]O[sub 2] by Ni and Al

Ni and Al can be substituted for Co in Li[Ni 1/3 Mn 1/3 Co 1/3 ]O 2 by increasing y and z in x LiNi 1/3 Mn 1/3 Co 1/3 O 2 -y LiNi 2/3 Mn 1/3 O 2-z LiNi 1/3 Mn 1/3 Al 1/3 O 2 (x + y + z = 1) pseudoternary solid solution systems. Additions of Al improve the thermal stability of the charged positive electrode material, at a cost of capacity reduction, which can be at least partially recovered by the addition of Ni. The composition Li[Ni (1/3+0.07) Mn 1/3 CO (1/3-0.2) Al 0.13 ]O 2 (x = 0.4, y = 0.2, z = 0.4) shows excellent thermal stability compared to Li[Ni 1/3 Mn 1/3 Co 1/3 ]O 2 , but similar specific capacity. The samples were synthesized via a coprecipitation-based synthetic method to prepare a mixed hydroxide precursor, followed by sintering with a Li salt. Such materials may find application in large-size Li-ion batteries targeted for vehicle applications.

Effect of Ni–Al atomic ratio on glass formation in La–Al–Cu–Ni bulk metallic glasses

Glass forming ability (GFA) and thermal properties were investigated for La 62Al 14(Cu 1− x Ni x ) 24 ( x = 0.2, 0.4, 0.6 and 0.8) bulk metallic glasses (BMGs). The experimental results show that in the La-based La–Al–(Cu–Ni) pseudo-ternary system, optimum glass formation actually occurs at the Ni:Al ratio of 1:1. It has been found that the GFA is much better in the range of unstable intermetallic compound (AlNi) than that of adjacent stable intermetallic compound (AlNi 3). The asymmetry of negative heat of mixing between the atomic pairs of La–Cu and La–Ni, Al–Cu and Al–Ni is also considered as another influencing factor of GFA. It might be an effective way to develop and design BMGs by adjusting the Ni–Al atomic ratio in Al–Ni-contained alloy systems.

Solid solutions in the Ag2Se-PbSe-Bi2Se3 system

The phase equilibria in the pseudoternary system Ag2Se-PbSe-Bi2Se3 have been studied using differential thermal analysis, x-ray diffraction, and microhardness measurements. The results have been used to construct the T-x phase diagram along the AgBiSe2-PbSe join and the 900-K section of the ternary phase diagram. The AgBiSe2-PbSe system contains a continuous series of cubic solid solutions with the NaCl structure. Their lattice parameter is an almost linear function of composition (a = 5.822–6.125 A). The formation of the solid solutions stabilizes the high-temperature phase of AgBiSe2: PbSe dissolution in this compound markedly reduces its polymorphic transformation temperature (590 K), down to room temperature at ≃ 10 mol % PbSe. In the Ag2Se-PbSe-Bi2Se3 system, the γ-phase exists in a broad region around the AgBiSe2-PbSe pseudobinary join.

High-Pressure Phase Equilibria of the Pseudoternary Mixture Sunflower Oil + Ethanol + Carbon Dioxide

Carbon dioxide can act as an expanding medium to carry out enzymatic reactions. Particularly, by dissolving CO2 in mixtures comprising lipid-type substances and simultaneously increasing the pressure, the miscibility among reactants is enhanced, viscosity of the reaction mixture decreases, and diffusion of reactants and products is improved. Knowledge about the phase equilibrium behavior of the reactive mixture + CO2 allows an adequate selection of conditions to achieve the homogeneous phase during reaction. In this work, phase equilibria data of the pseudoternary system sunflower oil + ethanol + CO2 at two different conditions (313 K and 13 MPa; 333 K and 20 MPa) were investigated to provide an understanding of the phase behavior of vegetable oil ethanolysis reactions in CO2-expanded media. Measurements were carried out by the analytical static method, using a variable-volume view cell equipped with a cold end light and a magnetic stirrer. Experimental tie-lines were determined for both types of equilibr...

Formation of gold nanoparticles in triblock terpolymer-modified inverse microemulsions

The influence of polystyrene (PS)- block–poly(1,4-butadiene) (PB)- block–poly(ethylene oxide) (PEO) and poly(1,4-butadiene)- block–polystyrene- block–poly(ethylene oxide) triblock terpolymers on the phase behaviour of the w/o microemulsion of the pseudo-ternary system made of water/sodium dodecylsulfate (SDS)/xylene–pentanol (1:1) was investigated by varying the sequence of the blocks. Independent on the terpolymer used an enlargement of L2 phase can be observed with increasing polymer concentration. Simultaneously, a decrease of the diameter of the mixed inverse terpolymer-surfactant micelles can be observed by dynamic light scattering. After cross-linking of the butadiene units, covalently closed nanocapsules with an average size between 20 and 30 nm can be observed. When the triblock terpolymer-modified microemulsion is used as a template for the nanoparticle formation, gold nanoparticles with diameters of about 10 nm are formed. After solvent evaporation, the terpolymer-modified, hydrophobic gold nanoparticles can be redispersed in a toluene–pentanol mixture, and eliminated from the non-soluble surfactant residue.

Gibbs energy of formation of CaCu 3Ti 4O 12 and phase relations in the system CaO–CuO/Cu 2O–TiO 2

The standard Gibbs energy of formation of CaCu 3Ti 4O 12 (CCTO) from CaTiO 3, CuO and TiO 2 has been determined as a function of temperature from 925 to 1350 K using a solid-state electrochemical cell with yttria-stabilized zirconia as the solid electrolyte. Combining this result with information in the literature on CaTiO 3, the standard Gibbs energy of formation of CCTO from its component binary oxides, CaO, CuO and TiO 2, has been obtained: Δ G f,ox o (CaCu 3Ti 4O 12)/J mol −1 (±600) = −125231 + 6.57 ( T/K). The oxygen chemical potential corresponding to the reduction of CCTO to CaTiO 3, TiO 2 and Cu 2O has been calculated from the electrochemical measurements as a function of temperature and compared on an Ellingham diagram with those for the reduction of CuO to Cu 2O and Cu 2O to Cu. The oxygen partial pressures corresponding to the reduction reactions at any chosen temperature can be read using the nomograms provided on either side of the diagram. The effect of the oxygen partial pressure on phase relations in the pseudo-ternary system CaO–CuO/Cu 2O–TiO 2 at 1273 K has been evaluated. The phase diagrams allow identification of secondary phases that may form during the synthesis of the CCTO under equilibrium conditions. The secondary phases may have a significant effect on the extrinsic component of the colossal dielectric response of CCTO.

Liquid–liquid equilibria for pseudo-ternary systems: (Sulfolane + 2-ethoxyethanol) + octane + toluene at 293.15 K

Liquid–liquid equilibrium data, both binodal and tie lines are presented for the pseudo-ternary systems: {(sulfolane + 2-ethoxyethano) (1) + octane (2) + toluene (3)} at 293.15 K. The experimental liquid–liquid equilibrium data have been correlated using NRTL and UNIQUAC models, and the binary interaction parameters of these components have been presented. The correlated tie lines have been compared with the experimental data. The comparisons indicate that both NRTL and UNIQUAC models satisfactorily correlated the equilibrium compositions. The tie-line data of the studied systems also were correlated using the Hand method.

Plotting of isolines of equal degree of precipitation in the FeCl2-Na2SO3-H2O system as the basis for isolation of ferrous sulfite from solution

Ferrous ions are removed from acidic solutions of nonferrous metal compounds by precipitation of Fe(OH) 3 after oxidation of Fe 2+ in solutions while increasing their pH. The mother solution of this product continues to contain valuable components, in particular, nonferrous metal ions irremovable by repeated repulping of the solution by acidified water. The utilization of ferric hydroxide is an important problem for various industries, first of all, nonferrous metallurgy [1]. We solved the problem of utilizing ferric hydroxide, which is now a production waste, by developing a technology based on sulfite conversion, the theoretical basis for which was a study of the pseudoquaternary system Fe(OH) 3 (H 2 SO 4 )‐Na 2 SO 3 ‐H 2 O [2]. For the first time, information was visualized by plotting on a plane of the multicomponent system a combination of two surfaces using two types of isolines: isolines of equal Fe(III) reduction state FeO 1.5 (final)/FeO 1.5 (initial) (%) and isolines of equal molar ratio Na 2 SO 3 /FeO 1.5 . This related the redox process with the reactant ratio and, thereby, clarified the mechanism of interaction in the system that is necessary for optimization and practical application of the process [3]. In the system Fe(OH) 3 (H 2 SO 4 )‐Na 2 SO 3 ‐H 2 O, three moles of Na 2 SO 3 react with one mole of Fe(OH) 3 to lead to virtually complete precipitation of ferrous sulfite. In this reaction, the reduction of Fe(III) to Fe(II) consumes two moles of Na 2 SO 3 , which is oxidized to dithionate Na 2 S 2 O 6 , and only one mole of Na 2 SO 3 is used to precipitate Fe(II) as sulfite FeSO 3 · 2.5H 2 O. In the technological process of sulfite conversion of ferrous cake, cake is initially separated by oxidizing the solution while increasing pH and then sulfitized to convert Fe(III) to Fe(II); ferrous sulfite precipitates; and sodium sulfite is recovered by thermal hydrolysis of the suspension, with SO 2 being distilled off and trapped by a Na 2 CO 3 solution. It seemed reasonable to develop a process of direct removal of ferrous sulfite from solution without a complex step of ferric hydroxide separation. For this purpose, it is necessary to investigate the FeCl 2 ‐Na 2 SO 3 ‐ H 2 O system at room temperature. This system has not yet been studied. The FeCl 2 ‐Na 2 SO 3 ‐H 2 O system was produced from a 0.18 M FeCl 2 solution (pH 2.6) and a 0.18 M Na 2 SO 3 solution (pH 8.4). The FeCl 2 solution was added to the H 2 SO 3 solution, and the mixture was supplemented with a 1 M H 2 SO 4 solution or a 1 M NaOH solution until a certain pH value from 4.0 to 1.5 at an interval of 0.5 was reached. H 2 SO 4 or NaOH was not a component of the pseudoternary system FeCl 2 ‐Na 2 SO 3 ‐(H + or OH ‐ )‐ H 2 O since either of the two substances was introduced only for reaching a certain pH value and was not involved in phase formation.

Synthesis and infrared spectroscopic properties of Tm3+-doped phosphate glasses

Abstract A vitreous domain is investigated in the pseudo-ternary system: P 2 O 5 –K 2 O–CaO–(5Al 2 O 3 ). The optimal glass composition has been defined as: 50% P 2 O 5 –30% K 2 O–15% CaO and [(5 − x )% Al 2 O 3 + x % Tm 2 O 3 ]. The physical and spectroscopic properties of the glass containing 0.75 mol% Tm 2 O 3 are reported. Judd–Ofelt intensity parameters have been determined and compared to those of Tm 3+ in other glasses. From the intensity parameters, spontaneous emission probabilities, excited state radiative lifetimes and branching ratios were calculated. The recorded fluorescence spectra have been used to estimate the stimulated emission cross-section of near infrared emissions. Gain cross-section spectrum has been calculated for the 3 F 4 → 3 H 6 transition which arises at 1.8 μm. The results are compared with those obtained for other materials investigated for infrared amplifiers in this spectral range.

Effect of α-Lactalbumin on Aerosol-OT Phase Structures in Oil/Water Mixtures

The ability of water-soluble, globular proteins to tune surfactant/oil/water self-assemblies has potential for the formation of biocompatible microemulsions and also plays a role in protein function at biological interfaces. In this work, we examined the effect of the protein alpha-lactalbumin on Aerosol-OT (AOT) phase structures in equivolume mixtures of oil and 0.1 M brine. In this pseudo-ternary system, surfactants are free to move to either oil or water phase to adopt phase structures close to the spontaneous curvature of the surfactants. Using small-angle X-ray scattering, we observed that addition of this protein changed the spontaneous curvature of the surfactant monolayer substantially. In the absence of protein, AOT adopted a negative spontaneous curvature to form spherical w/o microemulsion droplets. When less than 1 wt % of alpha-lactalbumin was added into the system, the w/o droplets became nonspherical and larger in volume, corresponding to an increase in water uptake into the droplets. As the protein-to-surfactant ratio increased, protein, surfactant, and oil increasingly partitioned toward the aqueous phase. There the protein triggered the formation of o/w microemulsions with a positive spontaneous curvature. These protein-containing structures exhibited significant interparticle attraction. We also compared the influence of two oil types, isooctane and cyclohexane, on the protein/surfactant interactions. We propose that the more negative natural curvature of the AOT/cyclohexane monolayer in the absence of protein prevented protein incorporation within organic phase structures and consequently pushed the system self-assembly toward aqueous aggregate formation.