Indicator Acid-Base Equilibria in Three Aqueous-Nonaqueous Solvent Mixtures<sup>1</sup>

Boni, K. A.; Strobel, Howard A.

doi:10.1021/j100884a003

Cited by 15 publications

(2 citation statements)

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“…Thus instead of having the structure (H 2 O) 4 4 H + is less than that in the compact structure. The latter will be holding the proton more firmly [20][21][22][23][24] . Figure 5 shows the effect of the changing composition of some organic solvents on the acidity function, for a definite acid concentration in case of pnitroaniline.…”

Section: Calculation Of Dissociation Constant (P ( S K) Bh + )mentioning

confidence: 99%

Study of the Dissociation Constants of Some Weak Indicator Bases in Ethyl Cellosolve - Water Solvent Mixtures

Alkhaldi¹,

Taha²

2008

sci

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Abstract.A spectrophotometric method has been used for the determination of the dissociation constants of some weak indicator bases in various ethyl cellosolve (ECS)-water solvent mixtures at 25ºC. The indicators used are p-nitro, o-nitro and m-nitroaniline. The dissociation constants are found to decrease with increase of ECS for all investigated indicators which indicates that the basicity of the medium is increased by the addition of solvent. The acidity function, H º , of HCl in water-ECS mixtures is also determined and is found to increase with concentration increase of organic solvent for a fixed acid concentration. This is explained owing to the salting-in effect which depends on the used solvent type.

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Section: Calculation Of Dissociation Constant (P ( S K) Bh + )mentioning

confidence: 99%

Study of the Dissociation Constants of Some Weak Indicator Bases in Ethyl Cellosolve - Water Solvent Mixtures

Alkhaldi¹,

Taha²

2008

sci

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“…Dissociation constants of p-nitroanilinium ion (BHt) were where a and (1 -a ) are the fractions of the indicator species present reported earlier in aqueous mixtures of protic solvents like in the neutral form (B) and the ionic form (BH'), respectively, and ethylene glycol (EG) (I), methanol (2,3), and acetic acid (4). acid form (BH'), completely base form (B), and the mixture of the earlier.…”

Section: Introductionmentioning

confidence: 96%

Spectrophotometric study of the dissociation of p-nitroanilinium ion in a binary aqueous-dipolar aprotic solvent system (H₂O + acetonitrile) at 25 °C: effect of the solvent

De¹,

De²

1984

Can. J. Chem.

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Thermodynamic dissociation constants (,K) of p-nitroanilinium ion (BH') have been determined at 25'C in aqueous solutions containing 20,40, 60, and 80 wt% acetonitrile (ACN) by spectrophotometric measurements. Standard Gibbs energies of transfer, AG;(B) of p-nitroaniline (B) from water to other solvents have been evaluated from the measurement of solubilities at 25°C. Solvent effect on the dissociation of the acid (BH'),, results in a characteristic minimum with a change in the solvent composition. The result in this protic -dipolar aprotic mixture (H20 + ACN) has been compared with that in aqueous mixture of protic solvent (HZO + ethylene glycol) available from literature. The solvent effect has been discussed in terms of the standard Gibbs energies of transfer AG; from water to aqueous mixtures of organic co-solvent of the uncharged base (B), the hydrochloride of the base (BHCI), and hydrochloric acid (HCI) and also in terms of the individual species involved in the dissociation process. The results indicate that solvent effect on dissociation is an involved process, guided by the combined effects of various types of solute-solvent interactions of the Brgnsted acid and its conjugate base in addition to the relative solvent basicities.

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Dissociation Constants of P‐Nitroanilinium Ion in Tetrahydrofuran‐Water Mixtures at 25°C by Spectrophotometric Measurements

El-Harakany

Ramadan

1984

J Chinese Chemical Soc

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Key Word Index-Dissociation constant; acidity function; ion-solvent interaction; thermodynamics of dissociation; ionization; solvent effect.A spectrophotometric method has been used for the determination of the dissociation constant of P·nitroanilinc indicator (which has a charge type A+BO) in various THF-water solvent mixtures at 2S"C. The dissociation constant is found to decrease with the addition of THF which indicates that the basicity of the medium is increased by the addition of the organic solvent.

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Indicator Acid-Base Equilibria in Three Aqueous-Nonaqueous Solvent Mixtures¹

Cited by 15 publications

References 1 publication

Study of the Dissociation Constants of Some Weak Indicator Bases in Ethyl Cellosolve - Water Solvent Mixtures

Study of the Dissociation Constants of Some Weak Indicator Bases in Ethyl Cellosolve - Water Solvent Mixtures

Spectrophotometric study of the dissociation of p-nitroanilinium ion in a binary aqueous-dipolar aprotic solvent system (H₂O + acetonitrile) at 25 °C: effect of the solvent

Dissociation Constants of P‐Nitroanilinium Ion in Tetrahydrofuran‐Water Mixtures at 25°C by Spectrophotometric Measurements

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Indicator Acid-Base Equilibria in Three Aqueous-Nonaqueous Solvent Mixtures1

Cited by 15 publications

References 1 publication

Study of the Dissociation Constants of Some Weak Indicator Bases in Ethyl Cellosolve - Water Solvent Mixtures

Study of the Dissociation Constants of Some Weak Indicator Bases in Ethyl Cellosolve - Water Solvent Mixtures

Spectrophotometric study of the dissociation of p-nitroanilinium ion in a binary aqueous-dipolar aprotic solvent system (H2O + acetonitrile) at 25 °C: effect of the solvent

Dissociation Constants of P‐Nitroanilinium Ion in Tetrahydrofuran‐Water Mixtures at 25°C by Spectrophotometric Measurements

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Indicator Acid-Base Equilibria in Three Aqueous-Nonaqueous Solvent Mixtures¹

Spectrophotometric study of the dissociation of p-nitroanilinium ion in a binary aqueous-dipolar aprotic solvent system (H₂O + acetonitrile) at 25 °C: effect of the solvent