The Solubility of the Chloromethanes in Water

 There are more than 150 papers that report on the solubility of the four chloromethanes in water. Volume 62 of the Solubility Data Series compiles and evaluates the papers concerned with the liquid–liquid solubility of the chloromethanes with water. A similar evaluation has not been carried out for the vapor–liquid solubility at a partial pressure up to the saturation vapor pressure of the four chloromethanes. This paper uses the liquid–liquid evaluated solubility values to calculate vapor–liquid Henry’s constants. They are compared with a compilation of Henry’s constants with good agreements between the calculated constants and the median of the compiled constants. It is believed that the calculated constants are a reliable set of values to use for the vapor–liquid solubility of the chloromethanes in water.     

Mutual Solubilities of Water and Alkanes

Summary.  The evaluation of mutual solubility data for systems water with n-alkanes, isoalkanes, and cycloalkanes along the three phase line is reported and a formula for the prediction of solubility of alkanes in water is developed. Then a cubic equation of state with an added term, which accounts for hydrogen bonding is used for correlation of liquid–liquid equilibrium data and for prediction of solubility of water in hydrocarbons using alkane in water solubility data. Comparison of the predicted and experimental solubilities is performed using all accessible experimental data. With this approach it is possible to predict the solubilities of water in alkanes with good accuracy over the temperature range up to about 20 K below critical temperature. Solubility of alkanes in water can also be calculated using experimental data for solubility of water in alkanes but results of these calculations are more sensitive to experimental errors of the data. Corresponding author: E-mail: macz@ichf.edu.pl Received August 5, 2002; accepted (revised) September 13, 2002 Published online March 13, 2003 RID="a" ID="a" Dedicated to Prof. Dr. H. Gamsj?ger on the occasion of his 70^th birthday anniversary     

Some Aspects of the Solubility of Gases in Liquids

Summary.  Henry’s law constants may usually be used to calculate solubilities of gases at low pressures. If experimental measurements are unavailable values of Henry’s law constants may be estimated by various methods. Several of these methods depend upon quantitative structure-property relationships. A method developed by Hine and Mookerjee depends on the assumption that each bond of a particular type makes approximately the same contribution to the molar free energy change when different organic gases are dissolved in water. The solubility of gases and also the rate at which gases dissolve in cloud droplets is important for the understanding of processes which occur in the atmosphere. A simple model for the uptake of gases by water is based on an analogy with the behaviour of an electric circuit containing resistances in series and in parallel. This model is important for the interpretation of experimental measurements of rates of gas uptake. E-mail: pfogg@compuserve.com Dedicated to Prof. Heinz Gamsj?ger Received September 21, 2002; accepted September 30, 2002 Published online April 3, 2003     

Chemistry of the Thermal Decomposition of Lutetium Selenities

Summary.  The solubility isotherm of the system Lu₂O₃–SeO₂–H₂O was studied at 100°C. The compounds of the three-component system were identified by Schreinemakers’ method and chemical, derivatograph and X-ray phase analyses after separation in the pure state: Lu₂(SeO₃)₃·4H₂O and LuH(SeO₃)₂·2H₂O. Received February 27, 2002; accepted (revised) April 26, 2002     

Thermodynamics of the Solubility of Water in 1-Hexanol, 1-Octanol, 1-Decanol, and Cyclohexanol

Summary. The solubility of water in 1-hexanol, 1-octanol, 1-decanol, and cyclohexanol was determined as a function of water activity by the isopiestic method at 298.2K. The solubility of water in the alcohol was expressed by a Setchenov type of equation and the correlation coefficients were related to the virial coefficients of the McMillan-Mayer theory of solution. From the solubility data both the activities and the osmotic coefficients of the alcohols were calculated. The Henrys law constants for the solubility of water in the alcohols are given. They depend linearly on the Gibbs energy of hydration. The excess Gibbs energy of mixing of water and alcohols is positive as a consequence of the strong intermolecular interactions of the two pure components of the mixture.     

Synthesis and Complexation Properties of Some Novel Lariat-Crown Ethers

Summary.  Several new lariat-crown ethers bearing either bridged bisdioxine or tetraoxaadamantane units as chiral substituents are prepared by reacting the corresponding amino-crown ether derivatives with the dimeric α-oxoketene, the latter obtained by flash vacuum pyrolysis of a furan-2,3-dione precursor. Complexation properties towards differently charged metal ions are investigated by ¹H NMR titration to obtain complexation constants (K _c -values for potassium/sodium rhodanides: 480–1100 mol dm⁻³), as well as extraction experiments to explore the metal ion transportation abilities of the new lariat crown derivatives. In particular, a significantly increased ability to transport metal ions from water into chloroform was found with spherical tetraoxaadamantyl derivatives when compared with the free amino-benzocrown ethers. Corresponding author. E-mail: kollenz@kfunigraz.ac.at Received July 5, 2002; accepted July 19, 2002     

High-pressure phase behaviour of the binary system {CO2 + cis-decalin} from (292.75 to 373.75) K

The phase behaviour of the {CO₂ (1) + cis-decalin (2)} binary system has been experimentally studied at temperatures ranging from (292.75 to 373.75) K. Saturation pressures, ranging from (15.9 to 490.5) bar, were obtained using a variable volume high-pressure cell by visual observation of phase transitions at constant overall composition. For this system, no literature data are available and the results obtained in this study reveal the occurrence of vapor–liquid, liquid–liquid, and vapor–liquid–liquid phase transitions in the investigated temperature range. A total of 133 experimental points are reported including bubble points, dew points, liquid–liquid phase equilibria, and coordinates of the three-phase line. The experimental data can be reasonably predicted by the PPR78 model in which the temperature-dependent binary interaction parameter is calculated by a group contribution method.     

Nitroxide Radicals of some N-Phenyl Substituted 1,4- and 1,2-Phenylenediamines

Summary.  Several N-phenyl substituted 1,4- and 1,2-phenylenediamines were oxidized using radicals and 3-chloroperbenzoic acid. EPR spectroscopy confirmed the generation of nitroxide radicals originating from the oxidation of the bridging -NH-group. No radical products suggesting the simultaneous reaction with the NH₂-group were observed. Only in the case of 1,4-phenylenediamine, a low concentration of nitroxide radical H–NO–C₆H₄–NH₂ was obtained. In o-aminodiphenylnitroxide the steric effect of the NH₂-group causes a partially asymmetrical spin density distribution in both phenyl rings. Corresponding author. E-mail: omelka@fch.vutbr.cz Received September 30, 2002; accepted October 4, 2002     

Combination of micellar extraction and GC-ECD for the determination of polychlorinated biphenyls (PCBs) in water

 The application of the solvent-free micellar extraction as an alternative method to the liquid–liquid extraction for the enrichment of polychlorinated biphenyls (PCBs) from ultrapure and natural water is presented. A nonionic surfactant was used to preconcentrate the PCBs. After a clean-up consisting of two columns (silica gel and Florisil) the analytes were identified and quantified by GC-ECD. Recoveries for spiked water were up to 100%. For highly contaminated seepage water of landfills liquid–liquid extraction is involving great problems with the phase separation of water and solvent. According to our results, the micellar extraction is superior to the liquid–liquid extraction for this difficult kind of aqueous matrix. Received: 20 February 1996/Revised: 20 May 1996/Accepted: 30 May 1996     

Combination of micellar extraction and GC-ECD for the determination of polychlorinated biphenyls (PCBs) in water

 The application of the solvent-free micellar extraction as an alternative method to the liquid–liquid extraction for the enrichment of polychlorinated biphenyls (PCBs) from ultrapure and natural water is presented. A nonionic surfactant was used to preconcentrate the PCBs. After a clean-up consisting of two columns (silica gel and Florisil) the analytes were identified and quantified by GC-ECD. Recoveries for spiked water were up to 100%. For highly contaminated seepage water of landfills liquid–liquid extraction is involving great problems with the phase separation of water and solvent. According to our results, the micellar extraction is superior to the liquid–liquid extraction for this difficult kind of aqueous matrix. Received: 20 February 1996/Revised: 20 May 1996/Accepted: 30 May 1996     

Unsymmetrical Diarylketones from Electron-rich Heterocyclic Arenes

Summary.  AlCl₃-mediated chlorocarbonylation of a first arene by oxalyl chloride followed by in situ Friedel-Crafts acylation of a second electron-rich arene expeditiously provides, in a one-pot procedure, either symmetrical or unsymmetrical benzophenones with yields ranging from 17–52%. Best results are obtained when the more activated substrate is used as the second arene. Another advantage is that the resultant benzophenone precipitates from the reaction mixture allowing facile workup. Corresponding author. E-mail: Poupaert@cmfa.ucl.ac.be Received October 4, 2002; accepted October 15, 2002 Published online March 6, 2003     

Solubilities of the Silver Halides in Aqueous Mixtures of Methanol,Acetonitrile, and Dimethylsulfoxide

Summary.  The solubilities of the silver halides in three non-aqueous solvents: methanol, acetonitrile, and dimethylsulfoxide, and in their aqueous mixtures, are reviewed. Values for the solubility product, K _SO , the enthalpies of solution, Δ _sol H ^o , and the equilibrium products for AgX ⁽ⁱ⁻¹⁾⁻ _i silver halide complexes, β _i , are listed and, where possible, compared. The solvent systems provide examples for three types of mixed aqueous solvent system: aqueous alcohol mixtures and aqueous mixtures with dipolar aprotic solvents that are weakly or strongly basic. The experimental data are discussed in terms of the solvation of the silver and halide ions in the mixed solvents. E-mail: Earle.Waghorne@ucd.ie Received September 30, 2002; accepted October 29, 2002 Published online April 7, 2003 RID="a" ID="a" Dedicated to Prof. Heinz Gamsj?ger on the occasion of his seventieth birthday     

Solid-Solute Phase Equilibria in Aqueous Solutions XVII [I]. Solubility and Thermodynamic Data of Nickel(II) Hydroxide

Summary.  The solubility of nickel(II) hydroxide (theophrastite) in water was determined as a function of temperature and ionic strength by the pH variation method. In each experiment the inert electrolyte medium was made up with sodium perchlorate. The experimental data were thermodynamically analyzed, and the standard solubility constant was extrapolated to zero ionic strength with the specific ion-interaction equation. Furthermore, the standard molar Gibbs energy and the enthalpy of formation for theophrastite, β-Ni(OH)₂, were evaluated. For all calculations, ChemSage and its optimizer routine were used. Received October 25, 2001. Accepted October 29, 2001     

Experimental Determination of the Isotherm at 15°C of the System Mg<Superscript>2+</Superscript>/Cl<Superscript>−</Superscript>, SO<Subscript>4</Subscript><Superscript>2</Superscript>–H<Subscript>2</Subscript>O

Summary.  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.  Corresponding author. E-mail: ariguib@planet.tn Received October 16, 2002; accepted (revised) December 3, 2002 Published online April 24, 2003 RID="a" ID="a" Dedicated to Prof. Dr. Heinz Gamsj?ger on the occasion of his 70^th birthday     

Microstructure and Magnetic Behaviour of Nanosized Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> Powders and Polycrystalline Films

Summary.  The object of investigation were the magnetic interactions in nanostructured Fe₃O₄ assemblies of two kinds (powder and film) where particles of similar size present nearly uniform domains in a close to planar arrangement with spacings sufficient for magnetic interactions. We discuss the use of the soft-chemistry method, i.e. the modified ‘ferrite plating’ (MFP) technique, for the synthesis of polycrystalline films of magnetite with nanosized crystallites. Received October 22, 2001. Accepted January 21, 2002     

Microwave Assisted Deprotection of N,N-Dimethylhydrazones in Water Using Palladium Chloride–Tin Chloride as Catalyst

Summary.  N,N-Dimethylhydrazones of ketones and aldehydes undergo facile cleavage to the corresponding carbonyl compounds upon exposure to microwaves in water containing a catalytic amount of PdCl₂–SnCl₂ in high yields. Corresponding authors. E-mail: rahman@umz.ac.ir Received December 27, 2001. Accepted (revised) February 6, 2002     

Phase equilibria of imidazolium ionic liquids and the refrigerant gas, 1,1,1,2-tetrafluoroethane (R-134a)

A number of applications with ionic liquids (ILs) and hydrofluorocarbon gases have recently been proposed. Detailed phase equilibria and modeling are needed for their further development. In this work, vapor–liquid equilibrium, vapor–liquid–liquid equilibrium, and mixture critical points of imidazolium ionic liquids with the hydrofluorocarbon refrigerant gas, 1,1,1,2-tetrafluoroethane (R-134a) was measured at temperatures of 25 °C, 50 °C, 75 °C and pressure up to 143 bar. The ionic liquids include 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)amide ([HMIm][Tf₂N]), 1-hexyl-3-methyl-imidazolium hexafluorophosphate ([HMIm][PF₆]), and 1-hexyl-3-methyl-imidazolium tetrafluoroborate ([HMIm][BF₄]). The effects of the anion and cation on the solubility were investigated with the anion having greatest impact. [HMIm][Tf₂N] demonstrated the highest solubility of R-134a. The volume expansion and molar volume were also measured for the ILs and R-134a. The Peng–Robinson Equation of State with van der Waals 2-parameter mixing rule with estimated IL critical points were employed to model and correlate the experimental data. The models predict the vapor–liquid equilibrium and vapor–liquid–liquid equilibrium pressure very well. However, the mixture critical points predictions are consistently lower than experimental values.     

Low-rate dynamic contact angles on poly(n-butyl methacrylate) and the determination of solid surface tensions

 Low-rate dynamic contact angles of 22 liquids on a poly(n-butyl methacrylate) (PnBMA) polymer are measured by an automated axisymmetric drop shape analysis-profile (ADSA-P). It is found that 16 liquids yielded non-constant contact angles, and/or dissolved the polymer on contact. From the experimental contact angles of the remaining 6 liquids, it is found that the liquid–vapor surface tension times cosine of the contact angle changes smoothly with the liquid–vapor surface tension, i.e. γ_lv cos θ depends only on γ_lv for a given solid surface (or solid surface tension). This contact angle pattern is in harmony with those from other inert and non-inert (polar and non-polar) surfaces [34–37, 45–47]. The solid–vapor surface tension calculated from the equation-of-state approach for solid-liquid interfacial tensions [14] is found to be 28.8 mJ/m², with a 95% confidence limit of ±0.5 mJ/m², from the experimental contact angles of the 6 liquids. Received: 12 September 1997 Accepted: 22 January 1998     

Apparent Molar Volume and Viscosity Studies on Some Carbohydrates in Solutions

Summary.  The apparent molar volume (φ_v) and viscosity (η) of L(+)-arabinose, D(+)-galactose, D(−)-fructose, D(+)-glucose, sucrose, lactose, and maltose in water and in 0.1% and 0.3% water-Surf Excel solutions were measured as a function of solute concentrations at 308.15, 313.15, and 323.15 K, respectively. The apparent molar volume (φ_v) of the carbohydrates was found to be a linear function of the concentration. From a φ_v versus molality (b) plot, the apparent molar volume at infinite dilution (), which is practically equal to the partial molar volume at infinite dilutions () of these substances was determined. The viscosity coefficients B and D for the carbohydrates were calculated on the basis of the viscosity of the solutions and the solvent using the Jones-Dole equation. The activation free energy for viscous flow (ΔG ^≠) of the solutions was also calculated using the Eyring equation. The carbohydrates showed structure making behaviour both in water and in water-Surf Excel solutions. When water-Surf Excel solutions and pure water solutions containing carbohydrate molecules are compared, the former were found to be more structured. The behaviour of these solutes in water and in water-Surf Excel solution systems is discussed in the light of solute–solvent interactions. Corresponding author. E-mail: chemistry_ru@yahoo.com Received March 19, 2002; accepted (revised) July 31, 2002 Published online February 24, 2003