Equilibrium constants of triethanolamine in major seawater salts

Brandariz, Isabel; Castro, Paula M.; Montes, María; Penedo, Francisco J.; Vicente, Manuel E. Sastre de

doi:10.1016/j.marchem.2006.05.005

Cited by 4 publications

(8 citation statements)

References 28 publications

(9 reference statements)

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“…It can be seen that p K a values increase with the increase of ionic strength. Such a trend is identical with that of the protonated triethanolamine, but different from monocarboxylic acids. , Therefore, it seems likely that the ILs with carboxyl group in their alkyl chain of cations could not be simply regarded as the traditional carboxylic acids.…”

Section: Resultsmentioning

confidence: 83%

Effects of Alkyl Chain Length and Solvents on Thermodynamic Dissociation Constants of the Ionic Liquids with One Carboxyl Group in the Alkyl Chain of Imidazolium Cations

Chen

Wang

2014

J. Phys. Chem. B

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Thermodynamic dissociation constants of the Brønsted acidic ionic liquids (ILs) are important for their catalytic and separation applications. In this work, a series of imidazolium bromides with one carboxylic acid substitute group in their alkyl chain ([{(CH2)nCOOH}mim]Br, n = 1,3,5,7) have been synthesized, and their dissociation constants (pKa) at different ionic strengths have been determined in aqueous and aqueous organic solvents at 0.1 mole fraction (x) of ethanol, glycol, iso-propanol, and dimethyl sulfoxide by potentiometric titrations at 298.2 K. The standard thermodynamic dissociation constants (pKa(T)) of the ILs in these solvents were calculated from the extended Debye-Hückel equation. It was found that the pKa values increased with the increase of ionic strength of the media and of the addition of organic solvent in water. The pKa(T) values also increased with the increase of the alkyl chain length of cations of the ILs. In addition, the effect of solvent nature on pKa(T) values is interpreted from solvation of the dissociation components and their Gibbs energy of transfer from water to aqueous organic solutions.

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Section: Resultsmentioning

confidence: 83%

Effects of Alkyl Chain Length and Solvents on Thermodynamic Dissociation Constants of the Ionic Liquids with One Carboxyl Group in the Alkyl Chain of Imidazolium Cations

Chen

Wang

2014

J. Phys. Chem. B

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“…where activity coefficients can be expressed by means of the Pitzer model, 2 which yields for the proton activity coefficient in NaCl solution 5 ln γ H + )…”

Section: Resultsmentioning

confidence: 99%

Protonation Constants of Procaine in Different Salts

et al. 2008

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Acid−base equilibrium constants for the two amino groups of the procaine molecule have been determined at 25 °C in different saline media (NaCl, KCl, and CaCl2), by means of potentiometric titrations. The Pitzer model has been used to deal with the ionic strength dependence of activity coefficients, and the parameters proposed by this theory have been obtained, including the thermodymanic dissociation constants, pK T. Equations describing the dependence of stoichiometric acid−base equilibrium constants versus ionic strength are given.

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“…In view of eq 3, log K 2 c is a function of the activity coefficient of the neutral species, log γ β-CD , and of the difference (log γ NoH +log γ NoH • CD + ). The activity coefficient for a neutral molecule, N, depends linearly on the ionic strength or salt concentration 12,[15][16][17] ln γ N ) K N,salt c salt (7) This is the well-known Setschenow equation, valid for low nonelectrolyte concentrations. Of course, K is a constant that depends on the neutral molecule and on the salt, and c represents the concentration of salt, which can be expressed in molarity or molality.…”

Section: Resultsmentioning

confidence: 99%

“…A matter not addressed in the earlier works, , that is, the variation of complexation constants with ionic strength I , is studied here. Potentiometry has been extensively used in this laboratory to obtain acid−base equilibrium constants of different systems in various saline media. − In fact, we previously determined the acid−base equilibrium constants for the two amino groups of the procaine molecule at 25 °C in NaCl solutions . These data are necessary in order to obtain the complexation constants of No and NoH + with β-CD as a function of sodium chloride concentration, the aim of this work.…”

Section: Introductionmentioning

confidence: 99%

“…The activity coefficients can be expressed as a function of the concentration of the salt used to keep ionic strength constant by means of different approaches. The Pitzer model 10,[5][6][7][8] is often used to describe the experimental behavior, although a simpler model for activity coefficients, specifically, a model with a Debye-Hu ¨ckel term plus a linear parameter (DH + L), will suffice for the interpretation of the results found in this system, as explained in the discussion. Several models for activity coefficients can be found in refs 10 to 12.…”

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confidence: 99%

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Complexation Constants of Procaine with β-Cyclodextrin in NaCl Media

Brandariz

Iglesias

2009

J. Chem. Eng. Data

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The complexation constants of neutral and protonated procaine (also called novocaine) with β-cyclodextrin have been obtained as a function of sodium chloride concentration, at 25 °C, using the potentiometric technique with a glass electrode. It was found that the formation of the complex with protonated procaine is not altered by the presence of the salt and the logarithm of the formation constant of the neutral complex increases slowly with ionic strength, varing linearly with salt concentration.

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Equilibrium constants of triethanolamine in major seawater salts

Cited by 4 publications

References 28 publications

Effects of Alkyl Chain Length and Solvents on Thermodynamic Dissociation Constants of the Ionic Liquids with One Carboxyl Group in the Alkyl Chain of Imidazolium Cations

Effects of Alkyl Chain Length and Solvents on Thermodynamic Dissociation Constants of the Ionic Liquids with One Carboxyl Group in the Alkyl Chain of Imidazolium Cations

Protonation Constants of Procaine in Different Salts

Complexation Constants of Procaine with β-Cyclodextrin in NaCl Media

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