Subsolidus equilibria in the system BaO.TiO2.Al2O3

The subsolidus phase equilibrium relations in the system BaO.TiO₂.Al₂O₃ have been investigated using conventional solid state reaction techniques and X-ray powder diffraction. The existence of three known ternary compounds, BaTi₅Al₂O₁₄, BaTiAl₆O₁₂, and Ba₃TiAl₁₀O₂₀, was confirmed and their stability relations were studied. Various tie-lines existing between the ternary compounds and the binary titanates and aluminates of barium were established and a subsolidus phase diagram showing the phase assemblages compatible at 1200°C is presented.     

Liquid-liquid equilibria for the system N-methylpyrrolidone + toluene + n-heptane: UNIFAC interaction parameters for N-methylpyrrolidone

Liquid-liquid equilibrium data obtained over the temperature range 15–50°C for the binary system N-methylpyrrolidone (NMP) + n-heptane are presented together with ternary data for the system NMP + toluene + n-heptane at 15, 25 and 40°C. The new data presented in this paper are correlated in terms of the well-known NRTL and UNIQUAC models. The experimental information obtained is used together with previous liquid-equilbrium results as a data base for the determination of UNIFAC interaction parameters between a new group, NMP, and the main groups CH₂, ACH, ACCH₂ and H₂O.     

Phase diagrams for the binary systems CaCl2-KCl and CaCl2-CaCrO4

Phase diagrams have been determined using differential thermal analysis for the binary systems CaCl₂-KCl and CaCl₂-CaCrO₄. CaCl₂-KCl phase diagrams have been previously reported but results were not consistent. No prior studies have been reported for the CaCl₂-CaCrO₄ system. In the CaCl₂-KCl binary system two eutectics have been located at 24.0 mole % KCl (m.p. 615°C) and 74.3 mole % KCl (m.p. 594°C). A double salt of composition CaKCl3 melting congruently at 741°C has been found. The CaCl₂-CaCrO₄ system is a simple eutectic system with the eutectic occurring at 23.4 mole % CaCrO₄ and melting at 660°C.     

Co3(HCOO)6 microporous metal-organic framework membrane for separation of CO2/CH4 mixtures

Continuous metal–organic framework‐type Co₃(HCOO)₆ intergrown films with a one‐dimensional zigzag channel system and pore aperture of 5.5 Å are prepared by secondary growth on preseeded macroporous glass‐frit disks and silicon wafers. The adsorption behavior of CO₂ or CH₄ single gases on the Co₃(HCOO)₆ membrane is investigated by in situ IR spectroscopy. It is shown that the isosteric heats of adsorption for CO₂ (17.7 kJ mol^?1) and CH₄ (14.4 kJ mol^?1) do not vary with increasing amount of adsorbed gases. The higher value of isosteric heat for CO₂ is an indication of the stronger interaction between the CO₂ and the Co₃(HCOO)₆ membrane. The Co₃(HCOO)₆ membrane is studied by binary gas permeation of CO₂ and CH₄ at different temperatures (0, 25, and 60 °C). The membrane has CO₂/CH₄ selectivity with a separation factor higher than 10, which is due to the unique structure and molecular sieving effect. Upon increasing the temperature from 0 to 60 °C, the preferred permeance of CO₂ over CH₄ is increased from 1.70×10^?6 to 2.09×10^?6 mol m^?2 s^?1 Pa^?1, while the separation factor for CO₂/CH₄ shows a corresponding decrease from 15.95 to 10.37. The effective pore size of the Co₃(HCOO)₆ material combined with the pore shape do not allow the two molecules to pass simultaneously, and once the CO₂ molecules are diffused in the micropores, the CH₄ is blocked. The supported Co₃(HCOO)₆ membrane retains high mechanical stability after a number of thermal cycles.     

The dehydration of CuSr2(HCOO)6 · 8H2O: A crystallographic study

The isothermal dehydration of CuSr₂(HCOO)₆ · 8H₂O single crystals as well as powdered material has been followed by several techniques, mainly X-ray diffraction and optical microscopy. Evidence was found of a two-stage process, with an early appearance of an amorphous state (attributed to internal dissolution) and further recrystallization of the stable phases. One of these (CuSr(HCOO)₄, monoclinic, P_c, Z = 2, a = 7.345(10) Å, b = 8.692(15) Å, c = 6.702(10)Å, β = 97.25(5)°) has not been reported so far in the literature. When dehydration takes place near room temperature, the remaining product (Sr(HCOO)₂) bears a topotactic relationship to the parent matrix ((hk0)//(hk0)′; 〈0k0〉//〈0k0〉′). A striking metric match between both (hk0) sections, as well as the absence of any common structural motive, suggest an inner epitactic growth as the most probable mechanism for the transformation.     

Measurements of the heats of dilution and description of the system H2O/H2SO4/HCl with a solvation model

Heat of dilution measurements have been performed on the system H₂O/H₂SO₄/HCl in the concentration range of 0.3 mol% to 20 mol% electrolyte and in the temperature range of 20°C to 60°C. The constituent binary systems H₂O/H₂SO₄ and H₂O/HCl could be described using the solvation model introduced by Engels [H. Engels, Anwendung des modells der lokalen zusammensetzung auf elektroytlösungen, Dissertation, RWTH Aachen, 1985]. The vapor–liquid-equilibria (VLE) and the thermal properties are described simultaneously by one set of parameters. Applying the solvation model to the ternary system H₂O/H₂SO₄/HCl, the measured heats of dilution as well as VLE-data taken from the literature could be predicted. The heat of dilution data are presented with a mean relative deviation of 3.5%. The boiling temperatures of the three sources of ternary VLE data considered in this paper are predicted with a mean absolute deviation of less than 1.2 K. The corresponding mean absolute deviations of the vapor mole fractions of HCl are within 0.06.     

Reactions in the M(HCOO)2-CS(NH2)2-H2O (M = Mg, Mn, Cd) systems at 25°C

Complex formation in the M(HCOO)₂-CS(NH₂)₂-H₂O (M = Mg, Mn, Cd) systems at 25°C is studied using the isothermal solubility method. In the Cd(HCOO)₂-CS(NH₂)₂-H₂O system, a congruently dissolving compound Cd(HCOO)₂ · 2CS(NH₂)₂ is found and characterized by X-ray powder diffraction and IR spectroscopy. The Mg(HCOO)₂-CS(NH₂)₂-H₂O and Mn(HCOO)₂-CS(NH₂)₂-H₂O systems are eutonics at this temperature. Data on carbamide and thiocarbamide complexes of divalent metal formates are systematized.     

Thermodynamics of electrolyte solutions: Activity and osmotic coefficients of aqueous NaCl in the NaCl-MgCl2-H2O system at different temperatures by the EMF method

The activity and osmotic coefficients of aqueous NaCI in the NaCl-MgCl₂-H₂O system at 25, 35 and 45°C and total ionic strengths of 0.5, 1, 2 and 3 were obtained by an EMF method using a sodium ion-selective electrode and an Ag/AgCl electrode. The Harned coefficients and Pitzer binary and ternary interaction coefficients were also determined.     

Synthesis and crystal chemistry of BaNd2Ti3O10, BaNd2Ti5O14, and Nd4Ti9O24

Two new ternary compounds BaNd₂Ti₃O₁₀ (1:1:3) and BaNd₂Ti₅O₁₄ (1:1:5) have been identified in the BaONd₂O₃TiO₂ system. Single crystals of the compounds were grown and unit cell dimensions and space group symmetry were determined. BaNd₂Ti₃O₁₀ is orthorhombic with a = 3.8655 ± 0.0003, b = 28.156 ± 0.003 and c = 7.6221 ± 0.0007 Å and possible space groups are Cmcm or Cmc2. The compound melts congruently at 1640 ± 20°C. BaNd₂Ti₅O₁₄ is also orthorhombic with a = 22.346 ± 0.002, b = 12.201 ± 0.001 and c = 3.8404 ± 0.0003 Å and possible space groups are Pbam and Pba2. This compound melts congruently at 1540 ± 20°C. Single crystals of the binary compound Nd₄Ti₉O₂₄ were also grown and found to be orthorhombic with a = 35.289 ± 0.003, b = 13.991 ± 0.001, c = 14.479 ± 0.001 Å, space group Fddd.     

Adsorption of protein on the surface of thermosensitive poly(methyl methacrylate) microspheres modified with the N-(2-hydroxypropyl)methacrylamide and 2-(methacryloyloxy)ethyl phosphorylcholine moieties

A series of microspheres composed of methyl methacrylate (MMA) and N-(2-hydroxypropyl)methacrylamide (HPMA), and/or 2-(methacryloyloxy)ethyl phosphorylcholine (MPC), i.e., binary copolymer microspheres [poly(HPMA-co-MMA)_KPS and poly(HPMA-co-MMA)_ABIP] and ternary ones [poly(HPMA/MPC-co-MMA)_KPS and poly(HPMA/MPC-co-MMA)_ABIP], were prepared by emulsifier-free emulsion copolymerization using potassium peroxodisulfate (KPS) or 2,2′-azobis[2-(imidazolin-2-yl)propane] dihydrochloride (ABIP) as initiators. The decrease in ζ-potential of the polymer microspheres is caused by the addition of the HPMA and/or MPC moieties. Equilibrium water content of poly(HPMA-co-MMA)_ABIP showed a remarkable swelling change with a change in response to temperature: the hydrated conformation at 28°C and the dehydrated one at above 40°C. The adsorption of protein on the polymer microspheres also changed in response to change in temperature. The ternary polymer microspheres effectively suppressed the adsorption both of Alb and Glo, less than binary ones. A series of polymer microspheres are expected to apply as a novel drug carrier with both thermosensitive and nonthrombogenic functions. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3349–3357, 1997     

On the microstructures of ethyl acetate/monoolein/water

A phase diagram, describing the behavior of the polar lipid monoolein (MO), water, and ethyl acetate (EtAc), is here presented as well as results from small angle X-ray scattering. MO is found to have a solubility of 60 wt.% in EtAc at 20 °C. No macroscopic aggregation of MO can, initially, be detected in the binary MO/EtAc solution even though MO forms solid crystals in concentrated samples when times goes by. In case of the ternary system small amounts of water, mainly bound to the lipid head groups, can be incorporated in the liquid EtAc/MO phase as water has a limited solubility in EtAc. For EtAc/water mass ratios below 2/3 EtAc is present into the reversed bicontinuous cubic and lamellar phases present in the binary MO/water system. To conclude, EtAc is mainly partitioned to the lipid membranes, with minor effects on spontaneous curvature. Hence, simple EtAc-addition has an effect similar to dehydration. For EtAc/water ratios above 2/3 the liquid crystalline phases dissolve. The phase behavior is here discussed in view of related phase behaviors for water-miscible solvent/MO/water systems. For instance, an interpretation of the swelling behavior of the sponge phase (L₃), present in the water-miscible solvent(s)/MO/water systems, shows that solvents partitioned to the polar domains strongly increases the spontaneous curvature of the MO-films. The reason is probably weaker hydrophobic interactions in interfacial regions. As expected, in case of water-miscible solvents, the ternary phase behaviors can be understood by consider water and water-miscible solvent as one “mixed solvent”.     

Experimental Determination of the Isotherm at 15°C of the System Mg2+/Cl?, SO42–H2O

 The diagram of the ternary system Mg²⁺/Cl⁻, SO₄ ²⁻–H₂O was established at 15°C by means of analytical and conductimetric measurements. Three compounds were found in this diagram, which are MgSO₄·6H₂O, MgSO₄·7H₂O, and MgCl₂·6H₂O. The solubility field of MgSO₄·7H₂O is important whereas those of MgSO₄·6H₂O and MgCl₂·6H₂O are small. The compositions (mass-%) of the two invariant points determined by the two methods are: MgSO₄:MgCl₂=2.73:33.80 and MgSO₄: MgCl₂=3.38:28.91. Both the measured and the calculated isotherm at 15°C have been used for modelling of the diagram Mg²⁺/Cl⁻, SO₄ ²⁻–H₂O between 0 and 35°C. The polythermal invariant point was approximately located between 15 and 10°C.     

Viscometric Analysis of Miscibility and Interactions for Binary,Ternary Polycarbonate/Brominated Polystyrene + Chloroform Systems at Different Temperatures

Viscosities of ternary systems consist of polycarbonate (PC)/brominated polystyrene (PBrS) in chloroform and their corresponding binary systems were measured at different temperatures (20, 25, and 30°C). All the measurements were carried out at the concentration ranges of 0.1–0.6 g·dL^?1. The mass ratio of PC to PBrS was selected as 75:25, 50:50, and 25:75 in the ternary solutions. Two empirical expressions of Huggins and Kraemer equations with three-parameters were used for reproducing of the experimental viscosity data. The fitting parameters were obtained for the corresponding temperatures. The miscibility criteria on the basis of the sign of Δ[η]_m based on the difference between experimental and ideal values of [η]_m, was calculated by applying the Garcia et al., theoretical equation. The effect of temperature on the viscosity data was also studied. The results from this method were correlated with the miscibility data obtained for the same system by differential scanning calorimeter (DSC) findings.     

Ternary liquid—liquid equilibria for acetonitrile—ethanol—cyclohexane and acetonitrile—2-propanol—cyclohexane

Liquid—liquid equilibrium data were obtained for two ternary systems: acetonitrile— ethanol—cyclohexane at 40°C, and acetonitrile—2-propanol—cyclohexane at 50°C. Binary vapor—Liquid equilibrium data were measured for acetonitrile—2-propanol at 50°C. The binary parameters of the Zeta and effective Zeta equations were evaluated from equilibrium data for binary pairs. The parameters obtained were used to predict the ternary liquid—liquid equilibrium data for six systems involving the present systems and the ternary vapor—liquid equilibrium data for one completely miscible system and two partially miscible systems without adding any ternary parameter. A heterogeneous area calculated by the Zeta equation is in general too large and does not decrease appreciably with increasing values of the third parameter ζ of the Zeta equation. However, the effective Zeta equation works much better than the original Zeta equation in data reduction.     

NaBO2-NaCl-Na2CO3, NaBO2- Na2CO3-NaMoO4, NaBO2- Na2CO3-NaWO4, and NaBO2-NaCl-Na2WO4 ternary systems

The phase diagrams of the NaBO₂-NaCl-Na₂CO₃, NaBO₂-Na₂CO₃-Na₂MoO₄, NaBO₂- Na₂CO₃-Na₂WO₄, and NaBO₂-NaCl-Na₂WO₄ ternary systems were studied by a calculation-experimental method and differential thermal analysis. The coordinates of ternary eutectics were determined: E ₁: 612°C, 16 mol % NaBO₂, 42 mol % NaCl, and 42 mol % Na₂CO₃; E ₂: 568°C, 12 mol % NaBO₂, 28 mol % Na₂CO₃, and 60 mol % Na₂MoO₄; E ₃: 575°C, 12 mol % NaBO₂, 32 mol % Na₂CO₃, and 56 mol % Na₂WO₄; E ₄: 628°C, 8 mol % NaBO₂, 20 mol % NaCl, and 72 mol % Na₂WO₄; and E ₅: 655°C, 9 mol % NaBO₂, 53 mol % NaCl, and 38 mol % Na₂WO₄.     

Properties of Systems Ba(HCOO)2-M(HCOO)2-H2O (M = Ca or Mg) at 25°C

The systems Ba(HCOO)₂-Ca(HCOO)₂-H₂O and Ba(HCOO)₂-Mg(HCOO)₂-H₂O were studied at 25°C by the solubility method. The effect of the ionic radii of doubly charged metals on the formation of double salts containing barium formate was considered.     

LiCl-LiBr-LiVO3 and LiCl-LiBr-Li2MoO4 ternary systems

Phase equilibria in the LiCl-LiBr-LiVO₃ and LiCl-LiBr-Li₂MoO₄ ternary systems have been investigated by differential thermal analysis. The following compositions have been revealed (mol %): eutectic in the LiCl-LiBr-LiVO₃ system (18.0% LiCl, 72.0% LiBr, and 10.0% LiVO₃) with a melting point of 464°C and specific enthalpy of melting of 213 kJ/kg, and a minimum in the LiCl-LiBr-Li₂MoO₄ system (27.0% LiCl, 48.0% LiBr, and 25.0% Li₂MoO₄) with a melting point of 444°C. The investigation of ternary systems including salts of alkali metals is of practical interest for chemical industry and metallurgy, where salt mixtures are used as fused electrolytes and heat carriers. Original Russian Text ? T.V. Gubanova, E.I. Frolova, I.K. Garkushin, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 7, pp. 1220–1223.     

Solubility in the NaCl-ZrOCl2-HCl-H2O system at 25, 50, and 75°C

Solubilities were studied in the NaCl-ZrOCl₂-HCl-H₂O water-salt system along the 28 wt % HCl section at 25, 50, and 75°C. This is a eutonic system. The compositions of the eutonic solution are as follows (wt % NaCl, ZrOCl₂ · 8H₂O, HCl, and H₂O, respectively): at 25°C, 0.26, 1.88, 27.4, and 70.46; at 50°C, 2.82, 2.68, 26.46, and 68.04; and at 75°C, 1.9, 16.1, 22.96, and 59.04.     

Gas-phase electron diffraction studies of the molecular structures of pentafluoroethane,C2F5H,and monofluoroethane,C2H5F

The molecular structures of C₂F₅H and C₂H₅F have been studied using gas-phase electron diffraction data collected on the Balzers KDG2 instrument. The following values for the main independent geometrical parameters were obtained (r_a values with e.s.d. in parentheses): in C₂F₅H, C-C = 1.525(4) Å, C-F(CHF₂) = 1.347 Å, C-F(CF₃) = 1.327 Å [C-F(av.) = 1.335(2) Å], ∠CCF(av.) = 110.0(2)°; in C₂H₅F, C-C = 1.502(5) Å, C-F = 1.397(4) Å, C-H = 1.097(2) Å. ∠CCF = 110.4(2)°, ∠CCH(av.) = 113.6(4)°. Evidence is presented to show that the electron diffraction data for C₂H₅F are not compatible with values for the bond angles deduced spectroscopically.     

KCl-KBO2-K2CO3, K2MoO4-KBO2-K2CO3, and K2WO4-KBO2-K2CO3 ternary systems

phase diagrams of KCl-KBO₂-K₂CO₃, K₂MoO₄-KBO₂-K₂CO₃, and K₂WO₄-KBO₂-K₂CO₃ ternary systems were studied by a calculation-experimental method and differential thermal analysis (DTA). The coordinates of ternary eutectics were determined to be E ₁: 622°C, 8.5 mol % KBO₂, 56.5 mol % KCl, and 35 mol % K₂CO₃; E ₂: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂MoO₄; E ₃: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂WO₄. The specific heats of melting of the eutectics were determined.