John L. Oscarson

Thermodynamic quantities for the interaction of SO 4 2? with H+ and Na+ in aqueous solution from 150 to 320C

AbstractThe aqueous reactions,

Thermodynamic quantities for the interaction of H+ and Na+ with C2H3O 2 − and Cl− in aqueous solution from 275 to 320°C

\begin{gathered} H^ + + SO_4^{2 - } = HSO_4^ - ,Na^ + + SO_4^{2 - } = NaSO_1^ - , \hfill \\ and H^ + + HSO_4^ - = H_2 SO_4 (aq) \hfill \\ \end{gathered}

Thermodynamic quantities for the protonation of amino acid amino groups from 323.15 to 398.15 K

were studied as a function of ionic strength(I) at 150, 175, 200, 250, 300 and 320°C using a flow calorimetric procedure. Log K, ΔH, ΔS and ΔCp values at I=0 were derived from the data at each temperature. Using these experimental values, equations describing log K, ΔH, ΔS and ΔCp at I=0 and temperatures from 150 to 320°C were derived for each system. The use of equations containing identical numbers of positive and identical numbers of negative charges on both sides of the equal sign (isocoulombic reaction principle) was evaluated as a technique for the extrapolation of log K values valid below 100°C to temperatures above 150°C. This evaluation indicated that the principle gives good estimates up to 320°C.

Thermodynamics of protonation of amino acid carboxylate groups from 50 to 125°C

Since 1980, the Design Institute for Physical Property Data® has sponsored Project 801 to develop, organize and make available to project sponsors a complete, critically evaluated compilation of thermophysical properties of industrial important chemicals. The database currently contains the properties of over 1700 chemicals and is arguably the best process design database in the world. Project 801 will continue to serve the needs of engineers and scientists in the future as new compounds and data are incorporated into the database and as new capabilities and technologies are implemented.

Thermodynamic quantities for the interaction of Cl− with Mg2+, Ca2+ and H+ in aqueous solution from 250 to 325°C

The aqueous reactions, {ie865-1}were studied as a function of ionic strength at 275, 300, and 320°C using a flow calorimetric technique. Log K, ΔH and ΔS values were determined from the fits of the calculated and experimental heats while ΔCp values were calculated from the variation of ΔH values with temperature. The log K and ΔH values for the first two reactions agree well with literature values at these temperatures. No previous results have been reported for the third reaction. The use of equations containing identical numbers of positive and identical numbers of negative charges on both sides of the equal sign (isocoulombic reaction principle) was applied to the log K values determined in this study. The resulting plots of log K for the isocoulombic reactions vs. I/T were approximately linear, which demonstrates that the ΔCp values for these reactions are approximately zero.

Liquid Membrane Separations of Metal Cations Using Macrocyclic Carriers

Abstract Emulsion membrane systems consisting of an aqueous metal salt source phase, a toluene membrane containing the macrocyclic ligand dicyclohexano-18-crown-6 (DC18C6) (0.02 M) and the surfactant sorbitan monooleate (3% v/v), and an aqueous 0.05 M Li4P2O7 receiving phase were studied with respect to the disappearance of metal from the source phase as a function of time. The salts Pb(NO3)2, Sr(NO3)2, TINO3, and LiNO3 were studied both singly and in mixtures of Pb(NO3)2 with each of the other salts. In all mixtures studied, Pb2+ was transported first, followed by the second cation (except Li+ which was not transported). An excess of a second salt with a common anion enhanced the transport of Pb2+. Modeling of these systems was discussed. Source phases containing basic (pH 11) K[Al(OH)4] solutions were studied using the same membrane and a 0.15 M H3PO4 receiving phase. K+ and Al(III) (as aluminate anion) were both found to transport in this system, but no transport of Al(III) and little transport of K+ w...

Determination of enthalpy of ionization of water from 250 to 350° C

Flow claorimetry has been used to study the interaction of protons with glycine, DL-α-alanine, β-alanine, DL-2-aminobutyric acid, 4-aminobutyric acid, and 6-aminocaproic acid in aqueous solutions at temperatures from 323.15 to 398.15 K. By combining the measured heats for amino acid solutions titrated with NaOH solutions with the heat of ionization for water, the log K, ΔHo, ΔSo, and ΔCpo values for the protonation of the amino groups of these amino acids have been obtained at each temperature studied. Equations are given expressing these values as functions of temperature. The ΔHo and ΔSo values increase while log K values decrease as temperacture increases. The trends for log K, ΔHo, ΔSo, and ΔCpo are discussed in terms of changes in long-range and short-range solvent effects. The trend in ΔHo, ΔSo, and ΔCpo values with temperature and with charge separation in the zwitterions is interpreted in terms of solvent-solute interactions and the electrostatic interaction between the two oppositely charged groups within the molecule.

Thermodynamic quantities for the ionization of nitric acid in aqueous solution from 250 to 319°C

Flow calorimetry has been used to study the interaction of glycine, DL-α-alanine, DL-2-aminobutyric acid, β-alanine, 4-aminobutyric acid, and 6-aminocaproic acid with protons in aqueous solutions from 323.15 K to 398.15 K and at 1.52 MPa. LogK, ΔH°, ΔS°, and ΔCp° for the protonation of the carboxylate groups of these amino acids have been obtained at each temperature studied. Equations are given expressing these values as functions of temperature. The protonation reactions are exothermic at lower temperatures and become endothermic as temperature increases. The logK, ΔH°, and ΔS° values are close together over the temperature range studied for the protonation of α-amino acids, i.e., glycine, DL-α-alanine, and 2-aminobutyric acid. At each temperature, the magnitudes of these thermodynamic quantities increase as the number of methylene groups between the amino group and the carboxylate group increases. The ΔCp° value for the protonation of the carboxyl group is found to lie between those of an isocoulombic reaction and a charge reduction reaction. At 323.15 K, the protonation reactions of the carboxylate groups have larger ΔCp° values which approach those associated with charge reduction reactions. As the temperature increases, ΔCp° decreases and approaches those found for isocoulombic reactions. This result is explained by considering long-range and short-range solvent effects. The trend in ΔH° and ΔS° with temperature and with charge separation in the zwitterions is interpreted in terms of solvent-solute interactions and the electrostatic interaction of the two oppositely charged groups within the molecule.