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  • 1
    Electronic Resource
    Electronic Resource
    Review of Selective Ion Separations at BYU Using Liquid Membrane and Solid Phase Extraction Procedures (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 29 (1997), S. 197-220 
    Details
    ISSN: 1573-1111
    Keywords: Selective ion separations ; macrocycle carriers ; liquid membranes ; solid phase extraction ; analytical separations ; environmental separations ; metallurgical separations ; precious metals separations ; nuclear waste separations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Research in selective ion separations at Brigham Young University hasinvolved the use of liquid membranes of the bulk, emulsion, thin sheetsupported, hollow fiber supported, and two-module hollow fiber supportedtypes as well as solid phase extraction using immobilized ligands. By use ofdesigned cation and anion selective macrocyclic ligands, it has beenpossible to accomplish a wide range of interesting separations. Theprinciples underlying the separations and a comparison of the advantages anddisadvantages of the various systems are given. Some of the solid phaseextraction systems have been commercialized by IBC Advanced Technologies,Inc. Examples of commercial applications are presented in the analytical,environmental, metallurgical, precious metals, and nuclear waste areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007952511806
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  • 2
    Electronic Resource
    Electronic Resource
    Proton ionizable crown compounds. 18. Comparison of alkali metal transport in a H2O-CH2Cl2-H2O liquid membrane system by four proton-ionizable macrocycles containing the dialkylhydrogenphosphate moiety (1989)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 7 (1989), S. 501-509 
    Details
    ISSN: 1573-1111
    Keywords: Proton-ionizable crown compounds ; metal ion transport ; liquid membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The macrocycle-mediated fluxes of alkali, alkaline earth, and several transition metal cations have been determined and compared in a H2O-CH2Cl2-H2O liquid membrane system using four water-insoluble macrocycles containing a dialkylhydrogenphosphate moiety. Transport of alkali metal cations by these ligands was greatest from a source phase pH = 12 or above into an acid receiving phase (pH = 1.5). Very low fluxes were observed for the transport of the alkaline earth cations and all transition metal ions studied except Ag+ and Pb2+ which were transported reasonably well by these new macrocycles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01080460
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  • 3
    Electronic Resource
    Electronic Resource
    Proton-ionizable crown compounds. 17. Transport studies of alkali metal ions in a H2O-CH2Cl2-H2O liquid membrane system by macrocycles containing two sulfonamide groups derived fromo- andm-phenylene diamine (1989)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 7 (1989), S. 487-499 
    Details
    ISSN: 1573-1111
    Keywords: Proton-ionizable crown compounds ; liquid membranes ; alkali metal ion transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The transport of alkali metal cations by several macrocycles possessing two sulfonamide groups as a part of an 18-, 20-, or 21-membered macroring has been studied. Some of these compounds were found to be more effective transport agents than the proton-ionizable pyridone- and triazole-containing crown ethers reported previously. The factors affecting transport, such as ring size, source and receiving phase pH, and the nature of the groups attached to the sulfonamide nitrogen atoms were examined. Also, extraction experiments by some of the ligands were performed. The behavior of sulfonamide type crowns in single and competitive transport of the alkali metal cations is explained. The mechanism of transport appears to be complex. Transport of one or two cations per molecule of the disulfonamide carriers occurs. Complexation of these cations appears to occur both within and outside the macrocycle cavity. Our results also suggest that kinetic factors may play a significant role in transport rates and selectivities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01080459
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  • 4
    Electronic Resource
    Electronic Resource
    Calorimetric determination of thermodynamic quantities for chemical reactions in the system CO2−NaOH−H2O from 225 to 325°C (1992)
    Springer
    Journal of solution chemistry 21 (1992), S. 825-848 
    Details
    ISSN: 1572-8927
    Keywords: Equilibrium constant ; Henry's constant ; enthalpy change ; entropy change ; heat capacity change ; flow calorimetry ; high temperature ; carbon dioxide ; carbonic acid ; sodium hydroxide ; sodium carbonate ; isocoulombic reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The phase equilibrium CO2(g)=CO2(aq) and the aqueous reactions CO 3 2− +H+=HCO 3 − , HCO 3 − +H+=CO2(aq)+H2O, and Na++CO 3 2− =NaCO 3 − were studied from 225 to 325°C using a flow calorimetric technique. Heats of mixing of gaseous CO2 with liquid H2O and with aqueous NaOH solutions were measured at these temperatures. Log K, ΔH, ΔS, and ΔCp values were determined for these reactions from the heat of mixing data. Equations for these thermodynamic quantities valid at infinite dilution (I=0) and 12.4 MPa are given as a function of temperature from 225 to 325°C. The log K and ΔH values agree well with literature values at these temperatures for the first and third reactions, but not for the second reaction. No previous results have been reported for the fourth reaction at high temperatures. The isocoulombic reaction principle is tested using the log K values determined in this study. This principle is found to be valid for the reactions where each charge on one side of the equation is balanced on the other side by a charge of the same sign and magnitude, but not for the reaction where two single negative charges (HCO 3 − and OH−) are balanced by one double negative charge (CO 3 2− ).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00651511
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  • 5
    Electronic Resource
    Electronic Resource
    Enthalpies of Dilution of Aqueous Solutions of LiCl, KCl, and CsCl at 300, 325, and 350°C (1997)
    Springer
    Journal of solution chemistry 26 (1997), S. 47-61 
    Details
    ISSN: 1572-8927
    Keywords: Dilution enthalpies ; activity coefficient ; alkali metal chlorides ; equilibrium constants ; enthalpy changes ; entropy changes ; heat capacity changes ; high temperature ; aqueous solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Dilution enthalpies, measured using isothermal flow calorimetry, are reported for aqueous solutions of LiCl, KCl, and CsCl at 300°C and 11.0 MPa, 325°C and 14.8 MPa, and 350°C and 17.6 MPa. The concentration range of the chloride solutions was 0.5 to 0.02 m. Parameters for the Pitzer excess Gibbs ion-interaction equation were determined from the fits of the experimental heat data. Equilibrium constants, enthalpy changes, entropy changes, and heat capacity changes for ion association of the chloride salts were estimated from the heat data. For all systems, the enthalpy and entropy changes were positive and had accelerating increases with temperature. The resulting equilibrium constants show significant, but smaller, increases with temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1024485028264
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  • 6
    Electronic Resource
    Electronic Resource
    Enthalpies of dilution of aqueous solution of LiCl, KCl, and CsCl at 300, 325, and 350°C (1997)
    Springer
    Journal of solution chemistry 26 (1997), S. 47-61 
    Details
    ISSN: 1572-8927
    Keywords: Dilution enthalpies ; activity coefficient ; alkali metal chlorides ; equilibrium constants ; enthalpy changes ; entropy changes ; heat capacity changes ; high temperature ; aqueous solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Dilution enthalpies, measured using isothermal flow calorimetry, are reported for aqueous solutions of LiCl, KCl, and CsCl at 300°C and 11.0 MPa, 325°C and 14.8 MPa, and 350°C and 17.6 MPa. The concentration range of the chloride solutions was 0.5 to 0.02m. Parameters for the Pitzer excess Gibbs ion-interaction equation were determined from the fits of the experimental heat data. Equilibrium constants, enthalpy changes, entropy changes, and heat capacity changes for ion association of the chloride salts were estimated from the heat data. For all systems, the enthalpy and entropy changes were positive and had accelerating increases with temperature. The resulting equilibrium constants show significant, but smaller, increases with temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02439443
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  • 7
    Electronic Resource
    Electronic Resource
    Enthalpies of Dilution of Aqueous Solutions of NaOH, KOH, and CsOH at 300, 325, and 350°C (1998)
    Springer
    Journal of solution chemistry 27 (1998), S. 183-194 
    Details
    ISSN: 1572-8927
    Keywords: Dilution enthalpies ; activity coefficients ; alkali metal hydroxides ; equilibrium constants ; enthalpy changes ; entropy changes ; heat capacity changes ; high temperature ; aqueous solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Dilution enthalpies, measured using isothermal flow calorimetry, are reported for aqueous solutions of KOH and CsOH at 300°C and 11.0 MPa, 325°C and 14.8 MPa, and for aqueous solutions of NaOH, KOH, and CsOH at 350°C and 17.6 MPa. Previously collected dilution enthalpies for aqueous solutions of NaOH at 300°C and 9.3 MPa and at 325°C and 12.4 MPa were included when fitting the Pitzer parameters. The concentration range of the hydroxide solutions was 0.5–0.02 molal. Parameters for the Pitzer excess Gibbs ion-interaction equation were determined from the fits of the experimental heat data. Equilibrium constants, enthalpy changes, entropy changes, and heat capacity changes for alkali metal ion association with hydroxide ion were estimated from the heat data. For all systems, the enthalpy changes and entropy changes were positive and had accelerating increases with temperature. The resulting equilibrium constants show significant, but smaller, increases with temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022661424398
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  • 8
    Electronic Resource
    Electronic Resource
    Determination of enthalpy of ionization of water from 250 to 350° C (1994)
    Springer
    Journal of solution chemistry 23 (1994), S. 747-768 
    Details
    ISSN: 1572-8927
    Keywords: Enthalpy change ; ionization of water ; high temperature ; flow calorimetry ; thermodynamic quantities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The enthalpy changes at zero ionic strength (ΔH°) for the ionization of water (H2O=H++OH−) were determined by flow calorimetry from the heats of mixing of aqueous NaOH and HCl solutions in the temperature range 250 to 350°C. Pitzer ion-interaction models developed by other workers were used to calculate enthalpies of dilution of aqueous NaOH, HCl, and NaCl solutions for the extrapolation of ΔH values from the conditions of the experiment to infinite dilution. Equations are derived for thermodynamic quantities (log K, ΔH°, ΔS°, ΔC p ° and ΔV°) for the ionization of water using the ΔH° values determined in this study from 250 to 350°C and literature log K and ΔH° values from 0 to 225°C. Smoothed values of log K, ΔH°, ΔS°, ΔC p ° , and ΔV° are presented at rounded temperatures from 0 to 350°C and at the saturation pressure of water for each temperature. The equations in the present study provide a better representation of experimental thermodynamic data from 0 to 350°C than the Marshall-Franck equation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00972670
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  • 9
    Electronic Resource
    Electronic Resource
    Enthalpy of dissociation of water at 325°C and LogK, ΔH, ΔS, and ΔC p values for the formation of NaOH(aq) from 250 to 325°C (1992)
    Springer
    Journal of solution chemistry 21 (1992), S. 803-824 
    Details
    ISSN: 1572-8927
    Keywords: Equilibrium constant ; enthalpy change ; entropy change ; heat capacity change ; flow calorimetry ; high temperature ; formation of water ; formation of sodium hydroxide ; isocoulombic reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The aqueous reactions H++OH−=H2O at 325°C and Na++OH−= NaOH(aq) at 250–325°C, were studied using a flow calorimeter. Heats of mixing of aqueous NaOH and HCl solutions were measured at 325°C. The enthalpy of water formation (ΔH=95.9 kJ-mol−1, valid at 12.4 MPa and infinite dilution) was obtained at this temperature from the heat of mixing data but differs significantly from that calculated from the Marshall-Franck equation. This calorimetric ΔH at 325°C was used in combination with literaturelog K and ΔH values at lower temperatures to derive equations representinglog K, ΔH, ΔS, and ΔCp for the formation of water from 250 to 325°C. Heats of dilution of aqueous NaOH solutions were measured at 250, 275, 300, and 325°C. Log K, ΔH, and ΔS for the formation of NaOH(aq) were determined at these temperatures from the fits of the calculated and measured heats while ΔCp values were calculated from the variation of ΔH with temperature. No previous experimental results have been reported for the formation of NaOH(aq). The isocoulombic reaction principle is tested using thelog K values obtained in this study. The plot oflog K vs. 1/T for the isocoulombic reaction NaOH(aq) +H+=H2O+Na+ is approximately linear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00651510
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