Solute Interaction Parameters Research Articles

Phase behaviour of rod with flexible side chains/coil/solvent systems: poly(α,l-glutamate) with tri(ethylene glycol) side chains, poly(ethylene glycol), and dimethylformamide

Phase behaviour is investigated for ternary solutions composed of rodlike α-helical poly(α,l-glutamate) having triethylene glycol monomethyl ether at the end of the side chains (P3EGLG), randomly-coiled poly(ethylene glycol), and N,N-dimethylformamide (DMF) as solvent. The solution containing lower molecular weight poly(ethylene glycol) (PEG10) separates into an isotropic phase, which is rich in PEG10, and an anisotropic (cholesteric) phase, which is rich in P3EGLG, when the total polymer volume fraction is higher than ca 0.13. The homogeneous anisotropic region, in which a detectable amount of PEG10 exists, is recognized along the P3EGLG-DMF axis in the triangle phase diagram. When the molecular weight of poly(ethylene glycol) is larger, additional phase-separation regions are observed: That is, isotropic-isotropic biphasic region and anisotropic-isotropic-isotropic triphasic region. Theoretical treatments based on the lattice model for nematic solutions are conducted for these rod/coil/solvent ternary systems. Calculated phase diagrams with considering flexible side chains of rodlike solute and isotropic interaction parameters are found to qualitatively reproduce the variation of the experimental phase behaviour with the change of the molecular weight of the coiled component.

Partition Coefficients and Polymer−Solute Interaction Parameters by Inverse Supercritical Fluid Chromatography

Inverse supercritical fluid chromatography (ISFC) is used to measure partition coefficients of five polar and nonpolar organic solids between supercritical CO2 and cross-linked poly(dimethylsiloxane) (PDMS) swollen with CO2. Polymer−solute interaction energies, which are determined from the partition coefficients, correlate with the heats of vaporization of the pure solutes. These interaction energies can be determined at ambient temperature for solutes that are too nonvolatile to study by inverse gas chromatography. Binary and ternary phase equilibria are modeled with lattice fluid theory including a term to account for the degree of polymer cross-linking. Experimental results indicate that solute adsorption on the support phase, which can be severe in packed columns, is negligible with the use of capillary columns.

Ion interaction approach to calculations of volumetric properties of aqueous multiple-solute electrolyte solutions

The ion interaction approach developed by Pitzer was used for the prediction of volumetric properties of mixed electrolyte solutions at 25°C based on parameters calculated from experimental data for single-solute electrolyte solutions. Such an approach was shown to be especially effective for application to the calculation of volumetric properties of natural hypersaline brines and of industrial electrolyte solutions of large complexity. The use of the latest recommended sets of volumetric ion interaction parameters for single electrolyte solutions and symmetrical mixing parameters for Na−K−Cl ion combinations considerably improved the precision of the density calculations of highly concentrated mixed electrolyte solutions and of various natural waters.

Estimation of Solubility Parameters of Poly(Methyl Methacrylate) and Derivatives by Inverse Gas Chromatography

Abstract Flory – Huggins polymer–solute interaction (χ1 2) parameters have been determined by inverse gas chromatography (i.g.c.) at 453–463 K for alkanes, alcohol, acetates, ketones and O – Xylene in PMMA, PEMA, PIBMA and Pt-BMA to estimate the polymer solubility parameters (δ2) Partial molar free energies of mixing (ΔG1 ∞) and weight fraction activity coefficients of solute probes at infinite dilution (Ω1 ∞) were calculated at temperature range 453–463 K.

Ca-rich carbonate melts; a regular-solution model, with application to carbonatite magma + vapor equilibria and carbonate lavas on Venus

Other| February 01, 1995 Ca-rich carbonate melts: A regular-solution model, with application to carbonatite magma + vapor equilibria and carbonate lavas on Venus Allan H. Treiman Allan H. Treiman Lunar and Planetary Institute, Houston, TX, United States Search for other works by this author on: GSW Google Scholar American Mineralogist (1995) 80 (1-2): 115–130. https://doi.org/10.2138/am-1995-1-212 Article history first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Allan H. Treiman; Ca-rich carbonate melts: A regular-solution model, with application to carbonatite magma + vapor equilibria and carbonate lavas on Venus. American Mineralogist 1995;; 80 (1-2): 115–130. doi: https://doi.org/10.2138/am-1995-1-212 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract A thermochemical model of the activities of species in carbonate-rich melts would be useful in quantifying chemical equilibria between carbonatite magmas and vapors and in extrapolating liquidus equilibria to unexplored PTX. A regular-solution model of Ca-rich carbonate melts is developed here, using the fact that they are ionic liquids, and can be treated (to a first approximation) as interpenetrating regular solutions of cations and of anions. Thermochemical data on systems of alkali metal cations with carbonate and other anions are drawn from the literature; data on systems with alkaline earth (and other) cations and carbonate (and other) anions are derived here from liquidus phase equilibria. The model is validated in that all available data (at 1 kbar) are consistent with single values for the melting temperature and heat of fusion for calcite, and all liquidi are consistent with the liquids acting as regular solutions.At 1 kbar, the metastable congruent melting temperature of calcite (CaCO3) is inferred to be 1596 K, with ΔHfus(calcite) = 31.5 ± 1 kj/mol. Regular solution interaction parameters (W) for Ca2+ and alkali metal cations are in the range −3 to −12 kj/mol2; W for Ca2+-Ba2+ is approximately −11 kj/mol2; W for Ca2+-Mg2+ is approximately −40 kj/ mol2, and W for Ca2+-La3+ is approximately +85 kj/mol2. Solutions of carbonate and most anions (including OH−, F−, and SO42−⁠) are nearly ideal, with W between 0 (ideal) and −2.5 kj/mol2. The interaction of carbonate and phosphate ions is strongly nonideal, which is consistent with the suggestion of carbonate-phosphate liquid immiscibility. Interaction of carbonate and sulfide ions is also nonideal and suggestive of carbonate-sulfide liquid immiscibility. Solution of H2O, for all but the most H2O-rich compositions, can be modeled as a disproportionation to hydronium (H3O+) and hydroxyl (OH ) ions with W for Ca2+-H3O+ ≈ 33 kj/mol2.The regular-solution model of carbonate melts can be applied to problems of carbonatite magma + vapor equilibria and of extrapolating liquidus equilibria to unstudied systems. Calculations on one carbonatite (the Husereau dike, Oka complex, Quebec, Canada) show that the anion solution of its magma contained an OH− mole fraction of ~0.07, although the vapor in equilibrium with the magma had P(H2O) = 8.5 × P(CO2). F in carbonatite systems is calculated to be strongly partitioned into the magma (as F−) relative to coexisting vapor. In the Husereau carbonatite magma, the anion solution contained an F− mole fraction of ~6 × 10−5.Calcite and anhydrite may be present on the surface of Venus, but they would not be molten at ambient surface temperature (660–760 K) because the minimum melt temperature (eutectic) for the calcite + anhydrite system is calculated to be 1250 K. The Venus atmosphere contains 5 ppb HF, which implies that the anion solution of a carbonate-rich magma in equilibrium with the atmosphere would contain a F− mole fraction of ~7 × 10−3, or about 0.1 wt%. Although this proportion of F is much enriched compared with the atmosphere, it would have little effect on phase relations of the carbonatite. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Determination of the solubility parameter of soybean oil by inverse gas chromatography

The solubility parameter of soybean oil, σ2, has been determined by the technique of inverse gas chromatography (IGC). Using soybean oil as the stationary phase, solute retention volumes were precisely determined as a function of temperature using 22 solute probes of varying solubility parameter (σ1). Solvent (oil)-solute interaction parameters, χ, were also calculated from the solute retention data and indicate complete miscibility of the solute probes with the soybean oil at conditions of infinite dilution. The χ values and their dependence on temperature were used to compute σ2 at 59, 79, 101, and 123°C. Over this temperature interval, the σ2 decreased from 7.9 to 6.9 cal1/2/cm3/2 with decreasing temperature, a trend consistent with the loss of cohesional energy density in the liquid soybean oil.

A modified perturbed hard-sphere equation of state

A modified perturbed hard-sphere equation of state, represented by the Carnahan—Starling equation with the van der Waals attractive part, has been investigated using the Mollerup approach for the energy parameter a for pure substances. The equation has been extended to mixtures, for both vapor—liquid equilibria and solid—supercritical fluid equilibria, using the Boublik—Mansoori equation with the same van der Waals attractive part. The vapor pressure, density, second virial coefficient, specific heat capacity and enthalpy were examined for pure substances. The new equation was also able to predict accurately the vapor pressures of fatty acids. The predictions of both vapor—liquid equilibria and solid—supercritical fluid equilibria, using the one fluid van der Waals mixing rules with one binary interaction parameter, are significantly better than those obtained by cubic equations of state, especially for large molecules. The predictions for solid—supercritical fluid systems were improved by incorporating solute—solute interaction parameters. Density dependent mixing rules were also examined.

Concentration-Dependent Thermodynamic Interaction Parameters for Polymer Solutions: Quick and Reliable Determination via Normal Gas Chromatography

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConcentration-Dependent Thermodynamic Interaction Parameters for Polymer Solutions: Quick and Reliable Determination via Normal Gas ChromatographyHans-Michael Petri and B. A. WolfCite this: Macromolecules 1994, 27, 10, 2714–2718Publication Date (Print):May 1, 1994Publication History Published online1 May 2002Published inissue 1 May 1994https://doi.org/10.1021/ma00088a010RIGHTS & PERMISSIONSArticle Views271Altmetric-Citations38LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (536 KB) Get e-Alerts Get e-Alerts

Viscometric measurement of the thermodynamic properties of dilute polystyrene solutions

We have investigated the use of the viscometric method for measuring the Flory interaction parameters for dilute polystyrene solutions in a range of solvents. Two ‘single point’ methods were used to estimate the intrinsic viscosity and these agreed well with the more conventional method of extrapolating results over a range of concentrations. Also, the interaction parameters derived from these intrinsic viscosity values showed good agreement with literature results. Values of the Flory interaction parameters are presented for 11 solvents, some of which have not previously been published.

Estimation of solid-vapor distribution coefficients in organometallic vapor phase epitaxy of II–VI semiconductors

We use equilibrium thermodynamics to explain non-linear alloy incorporation in the organometallic vapor phase epitaxy (OMVPE) of ternary II–VI compounds such as ZnSe x S 1 − x and Hg 1 − x Cd x Te. Our analysis includes the effects of incomplete decomposition of gas phase reactants as well as non-ideal solution effects in the product film. As an extension of our discussion of the specific II–VI systems above, we derive general formulas which can be applied to any OMVPE system for the limiting cases of complete or absent anion reactant decomposition. These formulas, which assume small dissociation for the solid films, replace the complicated procedure of free energy minimization with direct calculation of entire solid-vapor distribution curves. The parameters involved are temperature, the solid solution interaction parameter, the initial VI/II ratio, and the ratio of dissociation constants for the binary components of the solid film. This approach also allows us to anticipate systems in which kinetic effects may be important, based on the observation of thermodynamically unpredicted results.

Pairwise solute–solute interaction parameters and their application to solvent and salt effects on the kinetics of chemical reactions in aqueous solutions

Dependences on the nature and molalities of added solutes of rate constants for reactions in aqueous solutions have been examined, using the formalism of transition-state theory, in terms of the corresponding dependences of activity coefficients for solutes. Activity coefficients for neutral reactants and transition states are discussed in terms of pairwise solute–solute interactions and then in terms of group interaction parameters using the Savage–Wood additivity of groups (SWAG) procedures. The treatment is extended to a consideration of trends in enthalpies of activation in terms of enthalpic interaction parameters. Systems are grouped into four classes on the basis of changes in hydrophobic and hydrophilic character of substrates on proceeding from initial to transition states and on the basis of the hydrophobic and hydrophylic character of added solutes. In the case of reactions between hydroxide and bromophenol blue anions the dependence of kinetic parameters on added salt is understood, using Pitzer's equations, in terms of charge-charge and pairwise ion-ion interactions, the latter accounting for specific salt effects.

The Atomic‐Scale Origin of the Strain Enthalpy of Mixing in Zincblende Alloys

The atomic‐scale structure of solid solutions, previously experimentally determined by extended x‐ray absorption fine structure, is used to model the strain energy associated with the local distortions in bondlengths and bond angles relative to those in the pure binary compounds. The distortion energy associated with the bondlength change was calculated to be , where is the mole fraction, and adding the contribution from the bond‐angle distortions leads to a total strain energy of . The composition dependence of the strain energy is the same as the regular solution enthalpy of mixing, , and the calculated value of the solid solution interaction parameter, , is in good agreement with the reported experimental value of 0.13 eV/atom‐pair for . Similar calculations are made for four other zincblende solid solutions for which the atomic‐scale structure has been determined, and the results suggest that local bond strain is the major contribution to the enthalpy of mixing. Generalization of the strain calculations leads to a second‐order dependence of the on the normalized difference in endmember lattice constants, with no adjustable parameters, and this result is compared to semiempirical models for .

The Gibbs free energy of mixing of natural silicate liquids; an expanded regular solution approximation for the calculation of magmatic intensive variables

The compositions of liquids coexisting with experimentally grown crystals of olivine, plagioclase, clinopyroxene, orthopyroxene, leucite, spinel, rhombohedral oxide, melilite and potassium feldspar are used to define, through mass action expressions of liquid/solid equilibrium, compositional derivatives of the Gibbs free energy of mixing of naturally occuring silicate liquids as a function of temperature, pressure and the fugacity of oxygen. The available experimental data describe these derivatives over a range of compositions which includes basic magmas. Therefore, for silicate liquids in this composition range, the topology of the Gibbs free energy of mixing can be approximated from experimental determinations of its derivatives. The majority of the existing thermodynamic data on the liquid phase is consistent with the application of regular solution theory to model the free energy of mixing. Strictly symmetric, temperature and pressure independent, regular solution interaction parameters are calibrated from this phase equilibrium data using regression techniques which have their basis in inverse theory. These techniques generate numerically stable interaction parameters which incorporate inter-variable correlation and account for experimental uncertainty. The regular solution model fits the available data on anhydrous silicate liquids to within the accuracy of the thermodynamic database +/−550 cals). Extensions to regular solution theory allow water solubility in more silica rich liquids to be modelled somewhat less accurately (+/−750 cals).

Formula omitted]Se phase equilibria: a regular associated solution model for the Ga-Se liquid

Se vapor pressures were measured by the dew point method for the binary system Ga 1· x Se x , 0.60 < x < 1.00 (Ga 2Se 3-Se), between 700 and 1050°C. The Se vapor pressure was found to decrease rapidly near x = 60 atomic% Se. The T- X and P- X liquidus curves are thermodymanically modelled by a regular associated solution model for the liquid phase, with the associate, Ga 2Se 3. The best fit to the data was obtained with 4000 cal/mole of Ga 2Se 3 for the regular solution interaction parameter and 0.10 for the degree of dissociation in the stoichiometric liquid ( x = 0.60).

Simple Solution Approaches in Phase Diagram Evaluation

ABSTRACTIn the beginning there were ideal solutions (Geneva 1966) [1] and lattice stability values were deduced for the transition elements. Next regular solution interaction parameters for second and third row transition elements were predicted from simple models (Cambridge 1970)[2] combined with the lattice stability values via computer methods to calculate binary and ternary phase diagrams. Line compounds were introduced for comparison with experimental phase diagram data. At Brunel (1971)[3] and Munster (1972)[4] the regular solution models were expanded to include subregular and higher order terms and since the origin of CALPHAD (1973)[5]many coupled sets of thermochemical and phase diagram descriptions have been derived and published. Examples of multicomponent phase diagram calculations applied to solution of industrial problems have been illustrated in the subject areas of transformations and stability in steels and superalloys, uranium alloys, SIALON materials, metallic and fluoride glasses, electronic materials, and novel materials refining and processing methods. [6-19]

Further investigation of the determination of solute interaction parameters by analysis of phase equilibria using a linear programming technique

Further investigation of the determination of solute interaction parameters by analysis of phase equilibria using a linear programming technique

Thermodynamics of α,ω-methoxy-poly(ethylene oxide)/n-alkane systems by gas—liquid chromatography

The gas-liquid chromatographic method has been used to measure the thermodynamic parameters of low molecular weight α,ω-methoxy-poly(ethylene oxide) with C 5–C 12 n-alkanes. High positive values of the solution interaction parameters and reduced residual enthalpies are obtained. The signs of the reduced residual entropies at infinite dilution of solvent can be predicted by the Flory-Orwoll-Vrij theory.

Equilibrium gel permeation: a single-photon counting spectrophotometer for studies of protein interaction.

When a small column or flow cell packed with gel particles is completely saturated with a solution containing molecular species of interest, the average cross-sectional area occupied by the solute (partition cross section) is conveniently and precisely determined by direct optical scanning. For a mixture of interacting solutes this equilibrium gel permeation measurement yields the weight average of the species partition cross sections and the variation of this quantity with solute concentration permits determination of the solute interaction parameters (stoichiometry, equilibrium constants). We have developed a computer-controlled single-photon counting spectrophotometer for these measurements. The instrument exhibits high precision over a wide range of optical density. With counting times in the range of 10-1000 s the standard deviations on optical densities of protein solutions measured at 220 nm are typically 0.0006 at 1 OD, 0.002 at 2 OD, 0.005 at 4 OD. Beer's law tests show that deviations from linearity are less than these precision limits. Partition cross-section measurements for proteins can be made with an accuracy of better than 0.001 and information can be obtained with protein solutions at least as low as 1 mug/ml.

A thermodynamic evaluation of the simplesolution treatment of the Ga-P, In-P and Ga-As systems

Compositions and vapor pressure along the group III-rich liquidus of the Ga-P, In-P and Ga-As systems have been used to compare the simple solution interaction parameters obtained both from the liquidus and from the vapor pressures. When the available thermodynamic data are used for the pure P or As liquid reference state, the interaction parameters from the liquid and vapor are different. This disagreement arises from the use of reference state vapor pressures for pure liquid As and P which do not take into account the fact those liquids are highly associated in the temperature range where there are experimental data. When modified reference state pressures are used, the simple solution interaction parameters obtained with critically selected liquidus compositions and with vapor pressures are the same. In all cases the simple solution approximation is consistent with a third law treatment of the vapor pressure data which yields for each system a standard heat for the reaction A III (s)+1/2C 2 v (g)≈A III C v (s). The recommended best standard heats are −44.5±0.5 kcal mole −1 for Ga-As, −45.4±0.5 kcal mole −1 for Ga-P and −35.0±1.0 kcal mole −1 for In-P.

Determination of solute interaction parameters by analysis of phase equilibria using a linear programming technique

A linear programming technique has been developed to generate solute interaction parameters by the simultaneous analysis of phase equilibria and available thermochemical information. The Pb-Sn system has been analyzed and the parameter αPbSn, defined as αPbSn = ln γPb (1−N Pb) 2 , has been deduced as a function of temperature and composition for the liquid and (Pb) solid solutions. The Pb-rich solvus curve computed using the α S PbSn function agrees very well with other estimates.