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.

Thermodynamic properties of aqueous organic solutes in relation to their structure. Part III. Apparent molal volumes and heat capacities of low molecular weight alcohols and polyols at 25 °C

1976 ◽  
Vol 54 (4) ◽  
pp. 624-631 ◽  
Author(s):  
Carmel Jolicoeur ◽  
Ghyslain Lacroix
Keyword(s):  
Butyl Alcohol ◽  
Heat Capacities ◽  
Apparent Molal Volume ◽  
Molal Volume ◽  
Specific Effects ◽  
Alkyl Groups ◽  
Tert Butyl Alcohol ◽  
Dilute Aqueous Solutions ◽  
Solute Interactions ◽  
Molal Volumes

The density and specific heat of dilute aqueous solutions of various alcohols and polyols have been measured at 25 °C. Such measurements have been carried out for the following solutes: methanol, ethanol, n-propanol, n-butanol, isobutanol, s-butanol, tert-butyl alcohol, n-pentanol. 3-pentanol, neo-pentanol, ethyleneglycol, 1,4-butanediol, 1,6-hexanediol, dimethyl-2,2-propanediol, 1,1,1-tris(hydroxymethyl)ethane, and pentaerythritol.The limiting apparent molal volume [Formula: see text] and heat capacities [Formula: see text] derived from these data exhibit some variations among the properties of isomers (e.g. branched vs. normal alkyl groups), but these variations cannot be conclusively attributed to specific effects in the hydration of the alkyl groups. On the other hand, the data allows one to derive group contributions to [Formula: see text] and [Formula: see text] namely [Formula: see text] for the methylene group, [Formula: see text] for the OH functional group and [Formula: see text] for the C—H of a terminal methyl group.The concentration dependence of [Formula: see text] brings out some interesting new features. With most of the alcohols, [Formula: see text] decreases with concentration, in a way related to the degree of hydrophobicity of the alcohol. Solute–solute interactions contribute to reduce [Formula: see text] of the hydrophilic solutes, but the opposite effect is observed with the most hydrophobic alcohols.

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.

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.

Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

1988 ◽  
Vol 53 (12) ◽  
pp. 3072-3079
Author(s):  
Mojmír Skokánek ◽  
Ivo Sláma
Keyword(s):  
Heat Capacity ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Dimethyl Sulfoxide ◽  
Liquidus Temperature ◽  
Molar Heat Capacity ◽  
Solid Phase ◽  
Zinc Nitrate ◽  
Heat Capacities ◽  
Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

Excess properties for binary liquid mixtures of propionic acid with aniline derivatives

1991 ◽  
Vol 69 (3) ◽  
pp. 369-372 ◽  
Author(s):  
Begoña Garcia ◽  
Rafael Alcalde ◽  
José M. Leal
Keyword(s):  
Propionic Acid ◽  
Dipole Moments ◽  
Specific Interaction ◽  
Liquid Mixtures ◽  
Excess Properties ◽  
Free Energies ◽  
Empirical Parameter ◽  
Excess Viscosities ◽  
Different Temperatures ◽  
Mole Volume

Excess viscosities, excess volumes, and excess free energies of activation for flow of the binary mixtures containing propionic acid with aniline, o-toluidine, o-anisidine, and o-chloroaniline were determined at five different temperatures from density and viscosity measurements. Based on the Regular Solutions Theory, the empirical parameter θ was calculated; this parameter is related to the viscosity, and also denotes the extent of the non-ideality of the system. The results obtained suggest the existence of acid–base interactions, as well as the formation of 1:2 complexes for the three first mixtures, and 2:1 complexes for o-chloro-aniline + propionic acid. The extent of the specific interaction decreases with an increase in the strength of the base, and increases with an increase in the dipole moments. The equatioin [Formula: see text] is proposed for predicting the mole volume of the mixtures, V, at any composition, Xi, as a function of the mole volumes of the pure components, Vi. Key words: binary mixture, excess properties, predicting mole volumes, propionic acid.

Heat capacities at constant volume, free volumes, and rotational freedom in some liquids

1971 ◽  
Vol 24 (9) ◽  
pp. 1817 ◽  
Author(s):  
DD Deshpande ◽  
LG Bhatgadde
Keyword(s):  
Heat Capacity ◽  
Free Volume ◽  
Heat Capacities ◽  
Organic Liquids ◽  
Velocity Of Sound ◽  
Velocity Data ◽  
Volume Analysis ◽  
Straight Lines ◽  
Rotational Freedom ◽  
Residual Heat

This paper presents the experimental results on the velocity of sound, densities, and heat capacities of eight organic liquids at 25�, 35�, and 45�C. Using Eyring's equation, the free volumes have been calculated from the sound velocity data. For pure liquids, a quantity Cv* = (Cv)L- (Cv)g- Cstr called the residual heat capacity is found to be linearly dependent on free volume. Analysis of the data for 34 liquids shows that a plot of residual heat capacity against the free volume gives a series of straight lines differing in slopes for different groups of liquids such as hydrocarbons, halogen-substituted hydrocarbons, alcohols, etc. This behaviour is ascribed as being due to different degrees of rotational freedom of molecules in these liquids.

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