Enhancement of hydrogen bonding in vicinal water; heat capacity of water and deuterium oxide in silica pores

Langmuir ◽  
1988 ◽  
Vol 4 (4) ◽  
pp. 878-883 ◽  
Author(s):  
Frank M. Etzler
Keyword(s):  
Heat Capacity ◽  
Hydrogen Bonding ◽  
Deuterium Oxide

Aqueous Nonelectrolyte Solutions. Part IX. Enthalpies of Mixing of Water and Deuterium Oxide with Ethylene Oxide

1971 ◽  
Vol 49 (11) ◽  
pp. 1830-1840 ◽  
Author(s):  
D. N. Glew ◽  
Harry Watts
Keyword(s):  
Hydrogen Bonding ◽  
Ethylene Oxide ◽  
Composition Range ◽  
Deuterium Oxide ◽  
Enthalpy Of Mixing ◽  
Water Systems ◽  
Oxide System ◽  
Water Proton ◽  
Oxide Systems ◽  
Enthalpies Of Mixing

Calorimetric enthalpies of mixing have been measured over the whole composition range for the water – ethylene oxide system at 10.75 and 20.00 °C and for the deuterium oxide – ethylene oxide system at 13.45 and 20.00 °C. Less extensive measurements have been made for dilute ethylene oxide solutions in water at 0.6 °C and in deuterium oxide at 4.1 and 7.3 °C. The experimental S-shaped, enthalpy of mixing – composition curves are interpreted in terms of solution hydrogen bonding changes, with particular reference to the hydrogen bonding of water. At low ethylene oxide mole fractions the deuterium oxide systems are more exothermal and at high ethylene oxide mole fractions more endothermal than the corresponding water systems. A good correlation is found between the enthalpy of mixing and the water proton magnetic resonance chemical shift for solutions with greater than 0.55 mol fraction of ethylene oxide.

The Hydrolysis of Disubstituted Alkyl Phosphorochloridates and N,N,N′,N′-Tetra-stibstituted Phosphorodiamidic Chlorides in Water and Deuterium Oxide: Heat Capacity of Activation and Kinetic Solvent Isotope Effects

1973 ◽  
Vol 51 (4) ◽  
pp. 597-603 ◽  
Author(s):  
E. C. F. Ko ◽  
R. E. Robertson
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Parameters ◽  
Alkyl Group ◽  
Deuterium Oxide ◽  
Isotope Effects ◽  
Potential Relationship ◽  
Mechanism Of Reaction ◽  
Solvent Isotope ◽  
Hydrolysis Of ◽  
Solvent Isotope Effects

The pseudo-thermodynamic parameters, ΔH≠, ΔS≠, and ΔCp≠ and the kinetic solvent isotope effects have been determined for the three alkyl-phosphorochloridates, where the alkyl group is ethylisopropyl and n-propyl; for tetra-methyl and tetra-ethyl phosphorodiamidic chlorides; the di-n-propyl and di-isopropyl analog, the di(isopropylmethylcarbinyl)phosphorochloridate and the tetra-ethylthiophosphorodiamidic chloride. These compounds have a potential relationship to compounds used as insecticides and as polymers. The mechanism of reaction is discussed on the basis of these data.

Apparent Molal Volumes and Heat Capacities of Urea and Methyl-Substituted Ureas in H2O and D2O at 25 °C

1974 ◽  
Vol 52 (9) ◽  
pp. 1709-1713 ◽  
Author(s):  
Patrick R. Philip ◽  
Gérald Perron ◽  
Jacques E. Desnoyers
Keyword(s):  
Heat Capacity ◽  
Hydrogen Bonding ◽  
Heat Capacities ◽  
Breaking Effect ◽  
Methyl Substitution ◽  
Apparent Molal Volumes ◽  
Hydrogen Bonding Interactions ◽  
Molal Volumes ◽  
Methylene Group ◽  
Structure Breaking

The apparent molal volumes and heat capacities of urea, 1,1- and 1,3-dimethylurea, and tetramethylurea were measured in H2O and D2O at 25 °C. From these data, urea–water interactions seem to cause an overall structure-breaking effect and the substituted ureas, an overall structure-making effect. The effect of the hydrogen-bonding interactions to the volume and heat capacity seems to be small compared with the intrinsic and hydrophobic contributions of a methylene group, as reflected by the isotope effect. Furthermore, transfer values seem to show a significant specificity to the degree and position of methyl substitution.

Thermodynamic and Transport Properties of Sodium Benzoate and Hydroxy Benzoates in Water at 25 °C

1973 ◽  
Vol 51 (13) ◽  
pp. 2129-2137 ◽  
Author(s):  
Jacques E. Desnoyers ◽  
Robert Pagé ◽  
Gérald Perron ◽  
Jean-Luc Fortier ◽  
Paul-André Leduc ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Hydrogen Bonding ◽  
Sodium Benzoate ◽  
Specific Interaction ◽  
Osmotic Coefficients ◽  
Heat Capacities ◽  
Excess Properties ◽  
Apparent Molal Volume ◽  
Molal Volume ◽  
Ortho Isomer

The densities, heat capacities, heats of dilution, osmotic coefficients, viscosities, and conductivities of sodium benzoate and the ortho, meta, and para isomers of sodium hydroxybenzoate have been measured in water at 25 °C. The densities and heat capacities of phenol solutions and the osmotic coefficients of aqueous potassium benzoate have also been determined. The addition of an —OH or a —COONa group on a benzene ring has little effect on the properties related to the effective size of the solute (apparent molal volume, Bη viscosity coefficient, and ionic conductivity) but decreases significantly the apparent molal heat capacity. The addition of an —OH group in the meta or para position of sodium benzoate has a similar effect. The large negative contribution to the heat capacity probably reflects the solute–solvent hydrogen bonding. The ortho isomer, which can form an internal hydrogen bond, has a significantly different behavior from that of the other isomers.The excess properties show no evidence of association at low concentrations although some specific interaction is apparent for the ortho isomer at high concentration. There seems to be some cation–anion structural attraction with the meta and para isomers which again may be related to the hydrogen-bonding ability of these solutes. Sodium and potassium benzoates show signs of association above 1 m.

Aqueous nonelectrolyte solutions. Part XVI. Formula of deuterium sulfide D-hydrate and its dissociation thermodynamic functions

2000 ◽  
Vol 78 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Colin W Clarke ◽  
David N Glew
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Functions ◽  
Standard Enthalpy ◽  
Approximate Formula ◽  
Deuterium Oxide ◽  
Equilibrium Constants ◽  
Hydrate Dissociation ◽  
Quadruple Point ◽  
Dissociation Equilibrium ◽  
Heat Capacity Changes

A method has been devised to approximate both the hydrate formula number n and the standard thermodynamic functions for hydrate dissociation from the temperature change of the hydrate former fugacity along a univariant three-phase (hl1g) equilibrium line. Thermodynamic equations are derived, their validity discussed, and an iterative method for their solution is described. The univariant (hl1g) equilibrium dissociation of deuterium sulfide D-hydrate (D2S·nD2O phase h) into gaseous deuterium sulfide (g) and liquid deuterium oxide (l1) has been treated to give approximate formulae and dissociation constants at 58 temperatures from 2.798 to 30.666°C. Dissociation equilibrium constants Kp(h–> l1g) have been represented as a function of temperature by a four-parameter equation which yields both values and standard errors (i) for ΔHot(h–> l1g) and ΔCpot(h–> l1g) the standard enthalpy and heat capacity changes for D-hydrate dissociation and (ii) for n = r the approximate formula number of the D-hydrate at each experimental temperature. The formula D2S·6.115D2O with standard error 0.018D2O is found for deuterium sulfide D-hydrate at lower quadruple point Q(hs1l1g) 3.392°C; an approximate formula D2S·5.840D2O with SE 0.019D2O is found at upper quadruple point Q(hs1l2g) 30.770°C. Key words: clathrate D-hydrate of deuterium sulfide, deuterium sulfide D-hyfrate, formula of deuterium sulfide D-hydrate, thermodynamics of clathrate hydrate dissociation, dissociation equilibrium constant of deuterium sulfide D-hydrate, standard enthalpy, and heat capacity changes for dissociation of deuterium sulfide D-hydrate.

The physical and thermodynamic properties of some associated solutions II. Heat capacities and compressibilities

1964 ◽  
Vol 278 (1375) ◽  
pp. 574-587 ◽  
Keyword(s):  
Heat Capacity ◽  
Hydrogen Bonding ◽  
Thermodynamic Properties ◽  
Ultrasonic Velocity ◽  
Atmospheric Pressure ◽  
Dipolar Interaction ◽  
Heat Capacities ◽  
Pressure Measurements ◽  
Associated Solutions ◽  
Volume Dependence

The heat capacities of liquid piperidine, tetrahy dropyran, and cyclohexane, and of binary mixtures formed therefrom , have been determined in the temperaturerange 20 to 60 °C at atmospheric pressure. Measurements of ultrasonic velocity and density have enabled adiabatic and isothermal compressibilities to be evaluated. The heat capacities at constant volume have been resolved into four components in the cases of cyclohexane and tetrahydropyran, the structural contributions being approximately 1/2 R and R cal mole -1 deg -1 respectively. For cyclohexane, the volume dependence of the heat capacity has also been calculated. Differences between molecular association due to dipolar interaction and that due to hydrogen bonding, evidenced by the properties of pure tetrahydropyran and piperidine, are also apparent in the excess heat capacities, excess compressibilities, and excess volumes of the systems.

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