Glass-electrode measurements over a wide range of temperatures: The ionization constants (5?90�C) and thermodynamics of ionization of aqueous benzoic acid

1975 ◽  
Vol 4 (4) ◽  
pp. 267-274 ◽  
Author(s):  
John G. Travers ◽  
Keith G. McCurdy ◽  
Douglas Dolman ◽  
Loren G. Hepler
Keyword(s):  
Benzoic Acid ◽  
Glass Electrode ◽  
Ionization Constants ◽  
Wide Range ◽  
Thermodynamics Of Ionization

Thermodynamics of Ionization of Benzoic Acid and Substituted Benzoic Acids in Relation to the Hammett Equation

1974 ◽  
Vol 52 (16) ◽  
pp. 2906-2911 ◽  
Author(s):  
Takeki Matsui ◽  
Hon Chung Ko ◽  
Loren G. Hepler
Keyword(s):  
Benzoic Acid ◽  
Ionization Constants ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
Good Linear ◽  
Calorimetric Measurements ◽  
Linear Relationships ◽  
Best Value ◽  
Substituted Benzoic Acids ◽  
Thermodynamics Of Ionization

We have made both ampoule and titration calorimetric measurements leading to ΔH0 of ionization of aqueous benzoic acid at 298 K, and have considered our results in relation to those from several earlier investigations in an effort to select the "best" value for this important quantity. We have also made calorimetric measurements leading to ΔH0 values for ionization of several substituted benzoic acids, and have selected "best" ΔH0 values for 15 meta- and para-substituted benzoic acids. It is found that there are good linear relationships between ΔG0, ΔH0, and ΔS0 values for most of these substituted benzoic acids. It is also found that the Hammett equation accounts well for ionization constants over the temperature range 278–318 K for all of these acids and accounts very well for ionization constants of those acids with positive σ substituent parameters.

THE IONIZATION CONSTANTS OF p-NITROPHENYLACETIC AND PHENYLMALONIC ACIDS

1933 ◽  
Vol 8 (5) ◽  
pp. 447-449 ◽  
Author(s):  
Steward Basterfield ◽  
James W. Tomecko
Keyword(s):  
Benzoic Acid ◽  
Nitro Group ◽  
Malonic Acid ◽  
Phenylacetic Acid ◽  
Ionization Constants ◽  
Side Chain ◽  
Cooh Group ◽  
Conductivity Data ◽  
Nitrobenzoic Acid ◽  
Phenylmalonic Acid

The ionization constants of p-nitrophenylacetic and phenylmalonic acids have been determined from conductivity data. The value of K for p-nitrophenylacetic acid at 25 °C. is 1.04 × 10−4, about twice that of phenylacetic acid. The nitro group in the nucleus has not as powerful an effect on the ionization when the COOH group is in the side chain as it has when both nitro group and COOH are in the nucleus. K for p-nitrobenzoic acid is six times as great as K for benzoic acid. K for phenylmalonic acid is 2. 77 × 10−3 as compared with 1.6 × 10−3 for malonic acid.

Thermodynamics of ionization of trans-crotonic and adipic acids in water; the silver – silver adipate electrode

1980 ◽  
Vol 58 (4) ◽  
pp. 323-327 ◽  
Author(s):  
Upendra Nath Dash ◽  
Uttam Kumar Nayak
Keyword(s):  
Adipic Acid ◽  
Silver Chloride ◽  
Ionization Constants ◽  
Thermodynamic Quantities ◽  
Liquid Junction ◽  
Different Temperatures ◽  
Heat Capacity Changes ◽  
Silver Silver ◽  
Silver Silver Chloride ◽  
Thermodynamics Of Ionization

The ionization constant, K, of trans-crotonic acid, and the first and second ionization constants, K1 and K2, of adipic acid have been determined in water at seven different temperatures ranging from 15 to 45 °C with the help of the cells without liquid junction using silver – silver chloride and quinhydrone electrodes. The variations of pK, pK1, and pK2 with temperature have been expressed by the equations[Formula: see text]and[Formula: see text]From the temperature coefficient of the ionization constants, the standard enthalpy, entropy, Gibbs energy, and heat capacity changes of the corresponding dissociation processes have been calculated. Using the values of ionization constants of adipic acid, the standard potential of the Ag(s)/Ag2Ad(s)/Ad2− electrode, and the related standard thermodynamic quantities for the electrode process[Formula: see text]have been calculated in water at those temperatures.

Some quantitative relationships for ionization reactions at high pressures

1975 ◽  
Vol 28 (5) ◽  
pp. 945 ◽  
Author(s):  
BS El'yanov ◽  
SD Hamann
Keyword(s):  
High Pressures ◽  
Good Description ◽  
Ionization Constants ◽  
Linear Free Energy Relationship ◽  
Free Energies ◽  
Ion Hydration ◽  
Linear Free Energy ◽  
Linear Relationships ◽  
Wide Range ◽  
Ionization Equilibria

A simple formula is proposed to describe the pressure dependence of the variable Φ in El?yanov and Gonikberg's linear free energy relationship for ionization reactions in solution at high pressure. ��� The expression, given in equations (10) and (12), provides a good description of the influence of pressure on ionization equilibria in aqueous solutions. It permits El'yanov's general linear relationships between Φ and ionization free energies, enthalpies and entropies, pH and Hammett's p parameter, to be expressed in terms of the pressure in convenient analytical forms. ��� The formula is shown to be consistent with the simple electrostatic theory of ion hydration, allowing for the effect of pressure on the dielectric constant of water. Combined with the theory, it provides a general means of predicting ionization constants over a wide range of pressures and temperatures simply from knowledge of the changes in molar volume, enthalpy and entropy which accompany the reactions at atmospheric pressure.

scholarly journals Thermodynamics of Ionization of Benzoic Acid and Some Substituted Benzoic Acids in 1,4-Dioxane--Water Mixtures.

1992 ◽  
Vol 46 ◽  
pp. 399-402 ◽  
Author(s):  
Dattatraya Vyankatesh Jahagirdar ◽  
Harri Lönnberg ◽  
S. Grundvig ◽  
Yngve Stenstrøm ◽  
Agha Zul-Quarnain Khan ◽  
...  
Keyword(s):  
Benzoic Acid ◽  
Benzoic Acids ◽  
Substituted Benzoic Acids ◽  
Thermodynamics Of Ionization

Thermodynamics of Ionization of Nitroethane in Water–Ethanol Solvent Mixtures

1974 ◽  
Vol 52 (10) ◽  
pp. 1910-1913 ◽  
Author(s):  
Takeki Matsui ◽  
Loren G. Hepler ◽  
Earl M. Woolley
Keyword(s):  
Mixed Solvent ◽  
Aqueous Ethanol ◽  
Equilibrium Constants ◽  
Glass Electrode ◽  
Solvent Mixtures ◽  
Calorimetric Measurements ◽  
Solvent Systems ◽  
Ionization Of Water ◽  
Thermodynamics Of Ionization ◽  
Acid Ionization

We have made glass electrode measurements that lead to values for the equilibrium constant for acid ionization of nitroethane in water and in aqueous ethanol mixed solvent systems. Calorimetric measurements have led to ΔH0 values for the acid ionization of nitroethane in water and in aqueous ethanol. These results have been combined to yield TΔS0 values for the ionization reactions in water and in aqueous ethanol. Our results have also been combined with previously reported equilibrium constants for ionization of water in aqueous ethanol to obtain thermodynamic data for the neutralization of nitroethane in the various solvent systems.

Sign in / Sign up

Export Citation Format

Share Document