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  • 1
    Electronic Resource
    Electronic Resource
    Complexation of Metal Ions with Azacrown Ethers Bearing an 8-Hydroxyquinoline Side Arm (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 29 (1997), S. 259-268 
    Details
    ISSN: 1573-1111
    Keywords: Crown ether ; metal ion selectivity ; equilibrium constant ; enthalpy change ; entropy change ; 8-hydroxyquinoline side arm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Thermodynamic quantities (log, K, ΔH, and TΔS) for theinteractions of six azacrown ethers each bearing an 8-hydroxyquinoline (CHQ)side arm (1-6) with Na+, K+, Ba2+, and Cu2+ were determined by calorimetrictitration in methanol solution at 25°C. The results indicate that theseligands form stable complexes with the cations studied. Ligands 1 and 3 thathave CHQ attached through position 7 (next to the OH group) show highselectivity for Cu2+ (log K values of 8.12 and 9.44, respectively) over Na+,K+, and Ba2+ by more than four orders of magnitude. On the other hand,ligands 2 and 4 that have CHQ attached through position 2 (next to thequinoline nitrogen group) form more stable complexes with Na+, K+, and Ba2+,but less stable complexes with Cu2+, than ligands 1 and 3. All ligandsinteract more strongly with K+ than with Na+. The K+/Na+ selectivity forligands 4 and 5 is about 1.5 log K units. All complexation reactions displaynegative enthalpy changes. In most cases the entropy changes are alsonegative, indicating that formation of the complexes is enthalpy driven. 1HNMR spectral experiments demonstrate coordination of the cations by alldonor atoms of the ligands including those of the CHQ arm. In all cases, theOH signal is observed in the 1H NMR spectra, suggesting that thecomplexation with the cations does not involve deprotonation of the CHQgroups in the ligands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007959629553
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  • 2
    Electronic Resource
    Electronic Resource
    Pyrimidino- and Proton-ionizable Pyrimidono-crown Ether Ligands: Synthesis and Preliminary Complexation Studies (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 29 (1997), S. 301-308 
    Details
    ISSN: 1573-1111
    Keywords: Crown ether ; pyrimidine-containing crown ether ; pyrimidone-containing crown ether ; benzylammonium complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Pyrimidino-crown ethers were prepared in 30-50% yields by reactingthe ditosylate derivative of the appropriate oligoethylene glycol with4-methoxy-5-methyl-2,6-pyrimidinedimethanol under basic conditions. A newmacrocyclic ligand containing a proton-ionizable pyrimidone subcyclic unitwas prepared in 88% yield by treating the appropriatepyrimidino-crown ether with 5 M NaOH in 50% (v/v) aqueous methanol.Preliminary complexation properties of some of these new compounds werestudied using various NMR spectral techniques. Good enantiomeric recognitionwas exhibited by a chiral pyrimidino-crown ether for the enantiomers of1-(α-naphthyl)ethylammonium perchlorate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007980102236
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and structural studies of hydrazino-crown ethers and thermodynamic studies of their interaction with transition, and post-transition metal ions and methyl ammonium ion (1990)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 8 (1990), S. 299-308 
    Details
    ISSN: 1573-1111
    Keywords: Crown ether ; hydrazine ; X-ray crystal structure ; methanol ; cation binding ; transition metals ; post-transition metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Hydrazino-crown ethers have been synthesized in only 3 or 4 steps starting from 1,2-diacetylhydrazine. The X-ray crystal structure of protonated hydrazino-19-crown-7 (2) showed that one of the hydrazino nitrogen atoms was directed outside the ring cavity. A solvent methanol molecule is held in the cavity of the host ligand by three hydrogen bonds involving two hydrogen atoms bonded to nitrogens of the ligand and the alcohol hydrogen of the methanol. The logK values for the interaction of2 with CH3NH + 3 , Ag+, Pb2+, and Cd2+ were much less than those for the interaction of symmetrical triaza-l8-crown-6 (5) with the same cations. Hydrazino-crown2 reduced silver ions to silver metal when a solution of2 and silver ions in DMSO was allowed to stand for several days.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01041886
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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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