Vapor — liquid and vapor — liquid — liquid phase equilibria of binary and ternary systems of nitrogen,ethene and methanol: Experiment and data evaluation

Zeck, S. and Knapp, H., 1986. Vapor—liquid and vapor—liquid—liquid phase equilibria of binary and ternary systems of nitrogen, ethene and methanol: experiment and data evaluation. Fluid Phase Equilibria, 26: 37–58.VLE and VLLE of three binary and one ternary system containing the components N₂, C₂H₄ and CH₃OH are investigated in a high-pressure phase equilibrium apparatus with vapor recirculation at temperatures 240 < T < 298 K and pressures 4 < p < 100 bar. Immiscibilities in the liquid phase are observed in the binary system C₂H₄CH₃OH with a lower critical end point and in the ternary system N₂C₂H₄CH₃OH.The experimental results are reported and compared with the results of other investigators and of available correlations.     

Prediction of non-isothermal ternary gas-phase breakthrough experiments based on binary data

The results of breakthrough experiments in an adsorption column packed with commercial activated carbon for three binary CO₂/N₂ mixtures as well as for two ternary CO₂/N₂/H₂ mixtures are presented. The experiments were carried out at two different temperatures (25 and 45 °C), four different pressures (1, 5, 10 and 20 bar) and three different flow rates. To analyze the experiments, the breakthrough profiles are simulated using a one-dimensional model consisting of material and energy balances together with the necessary constitutive equations. Transport parameters such as the heat and mass transfer coefficients are fitted to the results from the experiments with the binary mixtures (CO₂/N₂) and then compared to parameters obtained in a previous work (Adsorption 18: 143–161, 2012) for binary CO₂/H₂ mixtures. Furthermore, the parameters obtained for binary mixtures are used to predict the outcome of breakthrough experiments with ternary CO₂/N₂/H₂ mixtures. These simulations are then tested by experiments, showing that their prediction capability is rather satisfactory for a large range of experimental conditions.     

In situ Investigations on the Formation and Decomposition of KSiH3 and CsSiH3

The system KSi‐KSiH₃ stores 4.3 wt % of hydrogen and shows a very good reversibility at mild conditions of 0.1 MPa hydrogen pressure and 414 K. 1 We followed the reaction pathways of the hydrogenation reactions of KSi and its higher homologue CsSi by in situ methods in order to check for possible intermediate hydrides. In situ diffraction at temperatures up to 500 K and gas pressures up to 5.0 MPa hydrogen gas for X‐ray and deuterium gas for neutron reveal that both KSi and CsSi react in one step to the hydrides KSiH₃ and CsSiH₃ and the respective deuterides. Neither do the Zintl phases dissolve hydrogen (deuterium), nor do the hydrides (deuterides) show any signs for non‐stoichiometry, i.e. all phases involved in the formation are line phases. Heating to temperatures above 500 K shows that at 5.0 MPa hydrogen pressure only the reaction 2CsSi + 3H₂ = 2CsSiH₃ is reversible. Under these conditions, KSiH₃ decomposes to a clathrate and potassium hydride according to 46KSiH₃ = K₈Si₄₆ + 38KH + 50H₂.     

The Semi-ideal Solution Theory. 4. Applications to the Densities and Electrical Conductivities of Mixed Electrolyte and Nonelectrolyte Solutions

Densities and electrical conductivities were measured for the ternary systems NaCl–mannitol(C₆H₁₄O₆)–H₂O, KCl–glycine(NH₂CH₂COOH)–H₂O, KCl–mannitol–H₂O, and NaBr–mannitol–H₂O at 298.15 K. Densities of the binary systems KCl–H₂O, NaBr–H₂O, glycine–H₂O and conductivities of the binary system NaBr–H₂O at 298.15 K were also measured. The measured densities were used to check the predictions of the semi-ideal solution theory. A new approach for predicting the conductivity of ternary electrolyte−nonelectrolyte mixture solutions in terms of the properties of their binary solutions of equal water activity is presented and compared with the measured values. The results show that the semi-ideal solution theory can provide good predictions for the densities and conductivities of the tested ternary electrolyte−nonelectrolyte solutions from the properties of their binary subsystems.     

Measurement and Correlation of Viscosities, Densities, and Water Activities for the System Poly(propylene glycol) + MgSO4 + H2O at 25°C

Viscosities, densities, and water activities for binary and ternary systems of poly(propylene glycol) 425 + H₂O and poly(propylene glycol) 425 + MgSO₄ + H₂O have been measured at 25°C. From density and viscosity measurements, excess volumes and excess viscosities of the binary poly(propylene glycol) 425 + H₂O, over the entire composition range, were obtained and correlated by means of a Redlich–Kister type equation. Viscosity, density. and water activity data for ternary system of poly(propylene glycol) 425 + MgSO₄ + H₂O were correlated by using a semiempirical equation.     

Metal hydride catalysis—Water formation on exposure of LaCo5Hz to O2

The formation of H₂O upon exposure of LaCo₅H_z to O₂ is studied at various temperatures in the vicinity of room temperature. In the equilibrium range of α and β hydride phases a predominantly linear dependence of rate on z (first-order rate law) is observed, Near room temperature no concomitant metal oxidation occurs, as the metal matrix can be rehydrided. The process is therefore a catalytic one. At higher temperatures the predominantly first-order reaction is modified by at least two concurrent reactions. They involve reaction of gas phase hydrogen and partial metal oxidation. Similar reactions of metal hydrides with NO and CO are briefly discussed.     

Vapor—liquid and vapor—liquid—liquid phase equilibria for binary and ternary systems for nitrogen,ethane and methanol: Experiment and data reduction

Zeck, S. and Knapp, H., 1986. Vapor-liquid and vapor-liquid-liquid phase equilibria for binary and ternary systems of nitrogen, ethane and methanol; experiment and data reduction. Fluid Phase Equilibria, 25: 302–322.VLE and VLLE are investigated for three binary and one ternary system containing N₂, C₂H₆ and CH₃OH in a high-pressure phase equilibrium apparatus with vapor recirculation at temperatures 240 < T < 298 K and pressures 4 < p < 75 bar. Two liquid phases are observed in the systems C₂H₆CH₃OH and N₂CH₃OH. Experimental results are reported and compared with available correlations.     

Modeling CO2 solubility in Aqueous Methyldiethanolamine Solutions by Perturbed Chain-SAFT Equation of State

CO₂ capture by aqueous alkanolamines treating is one of the prevalent methods to reduce carbon dioxide emissions and to help environmental problems. For realizing more the thermodynamics of the CO₂–MDEA–H₂O, the PC-SAFT equation of state was used to simulate the absorption of carbon dioxide by MDEA (methyldiethanolamine). A correlation for temperature-dependent binary interaction parameter were calculated by excess enthalpy data for aqueous MDEA at low temperatures (lower than 350 K), and then this binary interaction parameter used to predict phase equilibria of ternary aqueous mixtures of MDEA with carbon dioxide. Smith–Missen algorithm and PC-SAFT EOS have been used to determine concentration of species in chemical equilibrium and physical equilibrium, respectively. In addition, for determining parameter sets of MDEA, vapor pressure and saturated liquid density data were used and different and probable association schemes were considered in parameter estimations. Results show 4(2:2, 0:0) association scheme for MDEA and 4(2:2) association scheme for water have better agreement with binary and ternary VLE experimental data.     

Phase equilibria in system LiCl–NaCl–H<Subscript>2</Subscript>O at 308 and 348 K

The solubilities and densities of the solutions in the ternary system LiCl–NaCl–H₂O at 308 and 348 K were determined by the method of isothermal dissolution equilibrium. There are one invariant point, two univariant isotherm dissolution curves, and two crystallization regions corresponding to monohydrate (LiCl · H₂O) and NaCl, respectively. This system at both temperatures belongs to hydrate type I, and neither double salt nor solid solution was found. A comparison of the phase diagram for the ternary system at 273–348 K shows that the area of crystallization region of LiCl · H₂O is decreased with the increasing of temperature, while that of NaCl is increased obviously. The solution density of the ternary system at two temperatures changes regularly with the increasing of LiCl concentration.     

Calcium–Rhodium–Hydride –- Synthese und Struktur

Calcium Rhodium Hydrides –- Synthesis and Structure The two ternary hydrides Ca₈Rh₅H₂₃ and Ca₈Rh₆H₂₄ can be synthesised by reacting calcium hydride with rhodium in a hydrogen atmosphere. X-ray investigations on powder samples and elastic neutron diffraction experiments on the deuterated compounds led to the complete structures. Both hydrides crystallise in cubic structure types representing a transition from the K₂PtCl₆ type to the perovskit type structure. The rhodium deuterium bond lengths and the atomic volume of deuterium were discussed.     

Thermal properties of PA 6 and PA 6 modified with copolyamides and layered silicates

This article focuses on the thermal properties of PA 6 and additives, i.e. ternary copolyamides, concentrates consisting of binary or ternary copolyamides + nanoadditive montmorillonite Bentonite 11958 or Cloisite 15A and PA 6 fibres modified with Bentonite, copolyamide and concentrate. The copolyamides are prepared from ε-caprolactam as a major comonomer and nylon salts AN2 from adipic acid + 1-(2-aminoethyl)piperazine and ADETA from adipic acid + diethylenetriamine. All copolyamides and concentrates exhibit lower melting temperatures T _m and lower melting enthalpies ΔH _m compared to neat PA 6. PA 6 fibres modified with 0.25–2.5 wt% MMT exhibit higher melting enthalpies in comparison with unmodified PA 6 fibres. PA 6 fibres modified with 10 wt% of ternary copolyamide containing 21.4 wt% of comonomers AN2 and ADETA have higher melting enthalpy as well. PA 6 fibres modified with 10 and 20 wt% of concentrate containing the same ternary copolyamide + 5 wt% of MMT have higher melting enthalpies and higher tensile strength in comparison with these characteristics of unmodified PA 6 fibres.     

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.     

K<Subscript>2</Subscript>SO<Subscript>4</Subscript>-KCl-H<Subscript>2</Subscript>O phase diagram in the area of heterogenization of homogeneous supercritical fluids

The experimental investigations of phase equilibria in the K₂SO₄-KCl-H₂O system at temperatures to 500°C and pressures to 100 MPa were directed to elucidate the phase transformation sequence that leads to the heterogenization of the supercritical fluid whose existence field propagates from the K₂SO₄-H₂O binary subsystem to the ternary system. We suggest that fluid heterogenization in the title ternary system is accompanied by the transformation of the metastable immiscibility field to stable equilibria at elevated temperatures (near 460°C) and unexpectedly high pressures (～60 MPa), despite the presence of a vapor phase.     

Densities and Conductivities of Aqueous N,N,N-Alkyloctyldimethylammonium Chloride at Different Temperatures

The simple equations for predictions of the density and conductivity of mixed electrolyte solutions were extended to the related properties of mixed ionic liquid solutions. The densities and conductivities were measured for the ternary solutions OOAC (N,N,N-dioctyldimethylammonium chloride) + OPAC (N,N,N-octylpentyldimethylammonium chloride) + H₂O, OOAC + N,N,N-octylbutyldimethylammonium chloride (OBAC) + H₂O, OPAC + OBAC + H₂O and their corresponding binary subsystems OOAC + H₂O, OPAC + H₂O, and OBAC + H₂O at (298.15, 303.15, and 308.15) K, respectively. The results were used to test the predictability of the extended equations. Comparison of the results shows that these simple equations can be used to predict the density and conductivity of the mixed ionic liquid solutions from the properties of their binary subsystems of equal ionic strength.     

Modeling the phase equilibria of hydrogen sulfide and carbon dioxide in mixture with hydrocarbons and water using the PCP-SAFT equation of state

The perturbed-chain polar statistical associating fluid theory (PCP-SAFT) equation of state is applied to correlate phase equilibria for mixtures of hydrogen sulfide (H₂S) and carbon dioxide (CO₂) with alkanes, with aromatics, and with water over wide temperature and pressure ranges. The binary mixtures of H₂S–methane and CO₂–methane are studied in detail including vapor–liquid, liquid–liquid and fluid–solid phase equilibria. Very satisfying results were obtained for the binary mixtures as well as for the ternary mixture of H₂S–CO₂–methane using the (constant) interaction parameters of the binary pairs.     

Glass formation in systems of mercury,cesium, and lead bromides

The results of studies of glass formation in the binary subsystems of the ternary system HgBr₂-PbBr₂-CsBr and in several samples whose compositions lie near ternary eutectic points of the indicated ternary systems are reported. The conditions for glass formation have been determined. The characteristic temperatures have been determined by DTA, and T _g /T _m ratios and H _R factors for glassy samples calculated.     

Bond critical points in the electronic structures of binary hydrides

The bond critical points of the binary hydrides formed by the elements of the first two rows of the periodic table have been calculated. Particular attention has been paid to the basis-set dependence of the bond critical points at the experimental equilibrium geometries, or where necessary at model geometries. With the exception of H₂S, stepwise extension of the basis set leads to a smooth convergence of the bond critical points to a set of values which appear to converge to the Hartree–Fock limit. For H₂S it is shownb that the position of the bodn critical point is not only more sensitive to the presence of polarization functions in the basis set, but depends strongly on the orbital exponents of the polarization functions. Extensive optimizations of the exponents of the polarization functions have been carried out with the (12s9p/5s) basis set for second-row hydrides. The effects of contracting the Huzinaga basis sets have been examined.     

Using (FH)2 and (FH)3 to Bridge the σ‐Hole and the Lone Pair at P in Complexes with H2XP,for X=CH3, OH,H, CCH,F, Cl,NC, and CN

Ab initio MP2/aug′‐cc‐pVTZ calculations are used to investigate the binary complexes H₂XP:HF, the ternary complexes H₂XP:(FH)₂, and the quaternary complexes H₂XP:(FH)₃, for X=CH₃, OH, H, CCH, F, Cl, NC, and CN. Hydrogen‐bonded (HB) binary complexes are formed between all H₂XP molecules and FH, but only H₂FP, H₂ClP, and H₂(NC)P form pnicogen‐bonded (ZB) complexes with FH. Ternary complexes with (FH)₂ are stabilized by F?H???P and F?H???F hydrogen bonds and F???P pnicogen bonds, except for H₂(CH₃)P:(FH)₂ and H₃P:(FH)₂, which do not have pnicogen bonds. All quaternary complexes H₂XP:(FH)₃ are stabilized by both F?H???P and F?H???F hydrogen bonds and P???F pnicogen bonds. Thus, (FH)₂ with two exceptions, and (FH)₃ can bridge the σ‐hole and the lone pair at P in these complexes. The binding energies of H₂XP:(FH)₃ complexes are significantly greater than the binding energies of H₂XP:(FH)₂ complexes, and nonadditivities are synergistic in both series. Charge transfer occurs across all intermolecular bonds from the lone‐pair donor atom to an antibonding σ* orbital of the acceptor molecule, and stabilizes these complexes. Charge‐transfer energies across the pnicogen bond correlate with the intermolecular P?F distance, while charge‐transfer energies across F?H???P and F?H???F hydrogen bonds correlate with the distance between the lone‐pair donor atom and the hydrogen‐bonded H atom. In binary and quaternary complexes, charge transfer energies also correlate with the distance between the electron‐donor atom and the hydrogen‐bonded F atom. EOM‐CCSD spin‐spin coupling constants ^2hJ(F–P) across F?H???P hydrogen bonds, and ^1pJ(P–F) across pnicogen bonds in binary, ternary, and quaternary complexes exhibit strong correlations with the corresponding intermolecular distances. Hydrogen bonds are better transmitters of F–P coupling data than pnicogen bonds, despite the longer F???P distances in F?H???P hydrogen bonds compared to P???F pnicogen bonds. There is a correlation between the two bond coupling constants ^2hJ(F–F) in the quaternary complexes and the corresponding intermolecular distances, but not in the ternary complexes, a reflection of the distorted geometries of the bridging dimers in ternary complexes.     

Studies on ion exchange equilibria and kinetics VI. Prediction of ion exchange equilibria of UO 2 2+ −Na+−H+ ternary system

Experimental data are reported for the ion exchange equilibria of the binary systems UO ₂ ²⁺ –H⁺, UO ₂ ²⁺ –Na⁺ and Na⁺–H⁺, and of the ternary system UO ₂ ²⁺ –Na⁺–H⁺ on a strong acid cation exchange resin 001X7 at 25 °C. It is found that the equilibria for any pairs of ions are essentially the same in binary and ternary mixtures and that the prediction method proposed by our laboratory for SO ₂ ^2– –Cl^––NO ₃ ^– -201X7 strong base anion exchange resin system is also applicable to the ternary system studied in this paper. The predictions of the ternary system UO ₂ ²⁺ –Na⁺–H⁺ based solely on the binary data without using resin phase activity coefficients are consistent with the experimental data.     

Binary and ternary complexes of copper(II) with some dihydroxycoumarins

The complexation behaviour of copper(II) with a series of selected dihydroxycoumarins has been studied. Copper(II) binary complexes with esculetin, daphnetin and their 4-methyl and 4-phenyl derivatives and ternary complexes having a secondary ligand, ammonia or pyridine have bean synthesized. The general composition of binary complexes has bean found to be [Cu (H₂O)₂ (HL)₂] and that of ternary complexes as [Cu (L) (X)₄] (where X = NH₃ or C₅H₅N). The magnetic studies indicate all the complexes to be monomeric in nature. IR studies show that one of the two phenolic hydroxyl groups present in the ligand is lost during complexation. It is concluded that of the four ligands attached to the copper atom dihydroxycoumarin is bound most firmly.