The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
Martí Rosés - One of the best experts on this subject based on the ideXlab platform.
-
Autoprotolysis in aqueous organic solvent mixtures. Water/dipolar protophilic solvent binary systems
Analytica Chimica Acta, 1997Co-Authors: Elisabeth Bosch, G. Fonrodona, Clara Ràfols, Martí RosésAbstract:Abstract The Autoprotolysis of binary aqueous mixtures of dimethyl sulfoxide, acetonitrile, acetone, tetrahydrofuran and 1,4-dioxan is studied. It is demonstrated that except for solvent mixtures very rich in water, the Autoprotolysis is produced by proton transfer from water to the dipolar organic solvent. Only in water rich mixtures the autoionization of water contributes appreciably to Autoprotolysis. It is also suggested that the so-called Autoprotolysis constant or ionic product of these pure organic solvents is in fact, produced by proton transfer from the very small amounts of water present in the medium to the organic solvent. Equations and parameters are presented that allow calculation of the Autoprotolysis constant for any solvent composition at 25 °C. The variation of the Autoprotolysis constant with temperature is also studied for dimethyl sulfoxide/water and acetone/water mixtures.
-
Autoprotolysis in aqueous organic solvent mixtures water dipolar protophilic solvent binary systems
Analytica Chimica Acta, 1997Co-Authors: Elisabeth Bosch, G. Fonrodona, Clara Ràfols, Martí RosésAbstract:Abstract The Autoprotolysis of binary aqueous mixtures of dimethyl sulfoxide, acetonitrile, acetone, tetrahydrofuran and 1,4-dioxan is studied. It is demonstrated that except for solvent mixtures very rich in water, the Autoprotolysis is produced by proton transfer from water to the dipolar organic solvent. Only in water rich mixtures the autoionization of water contributes appreciably to Autoprotolysis. It is also suggested that the so-called Autoprotolysis constant or ionic product of these pure organic solvents is in fact, produced by proton transfer from the very small amounts of water present in the medium to the organic solvent. Equations and parameters are presented that allow calculation of the Autoprotolysis constant for any solvent composition at 25 °C. The variation of the Autoprotolysis constant with temperature is also studied for dimethyl sulfoxide/water and acetone/water mixtures.
-
Autoprotolysis in aqueous organic solvent mixtures water alcohol binary systems
Analytica Chimica Acta, 1996Co-Authors: G. Fonrodona, Elisabeth Bosch, Clara Ràfols, Martí RosésAbstract:By use of a previously derived equation, the main factors that contribute to Autoprotolysis are studied for different water/ alcohol mixtures. These factors are: autoionization of water, autoionization of the alcohol, and proton transfer from water to the alcohol or from the alcohol to water. The most important factors seem to be the proton transfer from the alcohol to water, and to a much lesser degree, the autoionization of water. The autoionization of the alcohol is only significant for pure alcohol. The different factors have been correlated with the solvent properties polarity and hydrogen-bond ability. An increase in these solvent properties favours autoionization and proton transfer, and therefore decreases the observed Autoprotolysis pK value. The proposed equation and the parameters calculated allow an accurate estimation of the Autoprotolysis pK value for any studied water/alcohol system.
-
Autoprotolysis in aqueous organic solvent mixtures.Water/alcohol binary systems
Analytica Chimica Acta, 1996Co-Authors: G. Fonrodona, Elisabeth Bosch, Clara Ràfols, Martí RosésAbstract:By use of a previously derived equation, the main factors that contribute to Autoprotolysis are studied for different water/ alcohol mixtures. These factors are: autoionization of water, autoionization of the alcohol, and proton transfer from water to the alcohol or from the alcohol to water. The most important factors seem to be the proton transfer from the alcohol to water, and to a much lesser degree, the autoionization of water. The autoionization of the alcohol is only significant for pure alcohol. The different factors have been correlated with the solvent properties polarity and hydrogen-bond ability. An increase in these solvent properties favours autoionization and proton transfer, and therefore decreases the observed Autoprotolysis pK value. The proposed equation and the parameters calculated allow an accurate estimation of the Autoprotolysis pK value for any studied water/alcohol system.
-
Autoprotolysis in aqueous organic solvent mixtures. Water-amide and water-amine binary systems
Analytica Chimica Acta, 1995Co-Authors: Clara Ràfols, Elisabeth Bosch, Martí Rosés, Agustin G. AsueroAbstract:Abstract The contribution of the autoionization of water and organic solvent, and the proton transfer between them to the overall Autoprotolysis of mixtures of water with amides ( N , N -dimethylacetamide, N -methylacetamide, acetamide, N , N -dimethylformamide, N -methylformamide and formamide) and with amines (butylamine, N , N -diethylaminoethanol and ethanolamine) is studied and compared. Proton transfer from water to the more basic amide, and specially amine, produces the Autoprotolysis in the intermediate solvent compositions and predominates over a wide range of solvent compositions. Autoionization of water predominates only for very low amide or amine contents. Autoionization of the amide or the amine can be important at intermediate and high organic solvent compositions if the pure amide or amine has a high Autoprotolysis constant (p K ap value lower than that of pure water). Because of the higher basicity of amines over amides, proton transfer from water to the amine produces very high Autoprotolysis constants for water-amine mixtures.
Sergio Alberto Dassie - One of the best experts on this subject based on the ideXlab platform.
-
Facilitated proton transfer via water Autoprotolysis-electron transfer coupled reactions at thick-film modified electrodes
Electrochimica Acta, 2020Co-Authors: Franco Martín Zanotto, Ricardo Fernandez, Sergio Alberto DassieAbstract:Abstract We present the derivation of a general mathematical model for facilitated proton transfer (FPT) reactions across a liquid|liquid (L|L) interface assisted by a protonatable neutral weak base at a thick organic film modified electrode setup. The effect of the explicit consideration of water Autoprotolysis is analysed. The model reported in this paper allows us to simulate the system under different experimental conditions, such as initial pH, organic phase to aqueous phase volume ratio and concentration of redox probe and transferring protonated species. This model for the FPT reactions via water Autoprotolysis in a system with two polarized interfaces is compared to our previous results calculated for a single polarizable interface [J. Electroanal. Chem. 578 (2005) 159–170]. We simulate a system with a single redox probe with two reversible non-simultaneous reduction processes with the goal of obtaining detailed mechanistic information of the facilitated proton transfer via water Autoprotolysis process at thick-film modified electrodes. Our conclusions can be straightforwardly applied in experiments. We focus on a system consisting of 7,7,8,8-tetracyanoquinodimethane (TCNQ) as a redox probe and 2,9-dimethyl-1,10-phenanthroline (2,9-DMP) as a neutral weak base.
-
facilitated proton transfer reactions via water Autoprotolysis across oil water interfaces spectroelectrochemical analysis
Electrochimica Acta, 2019Co-Authors: Sergio Alberto Dassie, Ricardo Fernandez, Rodrigo A. Iglesias, Vega F MercadoAbstract:Abstract In this paper, we present an integrated experimental-theoretical approach to evaluate the spectroelectrochemical response of the facilitated proton transfer processes via water Autoprotolysis at the liquid|liquid (L|L) interface. The aim of these studies is to confirm theoretically and experimentally the pH gradients generated at the L|L interface using coupled electrochemical and spectroscopic techniques. The spectroelectrochemical measurements are performed using a parallel beam configuration, where the light beam passes at grazing incidence over the L|L interface. pH gradients generated by proton transfer assisted by Quinidine via water Autoprotolysis are evaluated by the direct measurement of the optical absorption of Thymol Blue, acting as a pH probe. Results obtained are correlated with a numerical model considering all equilibria involved at both phases.
-
Facilitated proton transfer reactions via water Autoprotolysis across oil|water interfaces. Spectroelectrochemical analysis
Electrochimica Acta, 2019Co-Authors: F. Vega Mercado, Ricardo Fernandez, Rodrigo A. Iglesias, Sergio Alberto DassieAbstract:Abstract In this paper, we present an integrated experimental-theoretical approach to evaluate the spectroelectrochemical response of the facilitated proton transfer processes via water Autoprotolysis at the liquid|liquid (L|L) interface. The aim of these studies is to confirm theoretically and experimentally the pH gradients generated at the L|L interface using coupled electrochemical and spectroscopic techniques. The spectroelectrochemical measurements are performed using a parallel beam configuration, where the light beam passes at grazing incidence over the L|L interface. pH gradients generated by proton transfer assisted by Quinidine via water Autoprotolysis are evaluated by the direct measurement of the optical absorption of Thymol Blue, acting as a pH probe. Results obtained are correlated with a numerical model considering all equilibria involved at both phases.
-
Effect of ligand protonation on the facilitated ion transfer reactions across oil|water interfaces. V. Applications of forced hydrodynamic conditions
Journal of Electroanalytical Chemistry, 2016Co-Authors: Franco Vega Mercado, Juan Manuel Ovejero, Ricardo Fernandez, Sergio Alberto DassieAbstract:Abstract Hydrodynamic forced conditions applied to the aqueous or the organic phase during a potential sweep can be used to elucidate the mechanisms of ion transfer across liquid|liquid interfaces. The aim of this study is to confirm experimentally the previous proposed global mechanisms of facilitated proton transfer via water Autoprotolysis and to extend them, controlling the mass transport. We show that proton transfer assisted by quinidine via water Autoprotolysis is an interesting example, where the ion transfer reaction occurs with the formation of different products in each phase, i.e., protonated weak base in the organic phase and the hydroxide ion in the aqueous phase. Furthermore, one of the reactants (water) is always in excess with respect to the other one (neutral weak base). These features provide unique characteristics to facilitated proton transfer via water Autoprotolysis to be explored by applying forced hydrodynamic conditions.
-
Facilitated anion transfer reactions across oil∣water interfaces
Journal of Electroanalytical Chemistry, 2010Co-Authors: Sergio Alberto DassieAbstract:Abstract In this paper we present the general equations for a model of anion transfer reactions across the oil∣water interface assisted by a neutral ligand. Our analysis mainly focuses on the effect of water Autoprotolysis. The equations reported here allow us to simulate the system under a variety of possible conditions. The formation of complex with j:k anion-to-ligand stoichiometry is analyzed. Three different models are compared: buffered solutions (BASA model) and unbuffered solutions with and without considering water Autoprotolysis (UBASA and UBAS model respectively). Moreover, the analytical relationships for the BASA model between half-wave potential and the initial concentration of anion and ligand are developed.
Elisabeth Bosch - One of the best experts on this subject based on the ideXlab platform.
-
Autoprotolysis in aqueous organic solvent mixtures. Water/dipolar protophilic solvent binary systems
Analytica Chimica Acta, 1997Co-Authors: Elisabeth Bosch, G. Fonrodona, Clara Ràfols, Martí RosésAbstract:Abstract The Autoprotolysis of binary aqueous mixtures of dimethyl sulfoxide, acetonitrile, acetone, tetrahydrofuran and 1,4-dioxan is studied. It is demonstrated that except for solvent mixtures very rich in water, the Autoprotolysis is produced by proton transfer from water to the dipolar organic solvent. Only in water rich mixtures the autoionization of water contributes appreciably to Autoprotolysis. It is also suggested that the so-called Autoprotolysis constant or ionic product of these pure organic solvents is in fact, produced by proton transfer from the very small amounts of water present in the medium to the organic solvent. Equations and parameters are presented that allow calculation of the Autoprotolysis constant for any solvent composition at 25 °C. The variation of the Autoprotolysis constant with temperature is also studied for dimethyl sulfoxide/water and acetone/water mixtures.
-
Autoprotolysis in aqueous organic solvent mixtures water dipolar protophilic solvent binary systems
Analytica Chimica Acta, 1997Co-Authors: Elisabeth Bosch, G. Fonrodona, Clara Ràfols, Martí RosésAbstract:Abstract The Autoprotolysis of binary aqueous mixtures of dimethyl sulfoxide, acetonitrile, acetone, tetrahydrofuran and 1,4-dioxan is studied. It is demonstrated that except for solvent mixtures very rich in water, the Autoprotolysis is produced by proton transfer from water to the dipolar organic solvent. Only in water rich mixtures the autoionization of water contributes appreciably to Autoprotolysis. It is also suggested that the so-called Autoprotolysis constant or ionic product of these pure organic solvents is in fact, produced by proton transfer from the very small amounts of water present in the medium to the organic solvent. Equations and parameters are presented that allow calculation of the Autoprotolysis constant for any solvent composition at 25 °C. The variation of the Autoprotolysis constant with temperature is also studied for dimethyl sulfoxide/water and acetone/water mixtures.
-
Autoprotolysis in aqueous organic solvent mixtures water alcohol binary systems
Analytica Chimica Acta, 1996Co-Authors: G. Fonrodona, Elisabeth Bosch, Clara Ràfols, Martí RosésAbstract:By use of a previously derived equation, the main factors that contribute to Autoprotolysis are studied for different water/ alcohol mixtures. These factors are: autoionization of water, autoionization of the alcohol, and proton transfer from water to the alcohol or from the alcohol to water. The most important factors seem to be the proton transfer from the alcohol to water, and to a much lesser degree, the autoionization of water. The autoionization of the alcohol is only significant for pure alcohol. The different factors have been correlated with the solvent properties polarity and hydrogen-bond ability. An increase in these solvent properties favours autoionization and proton transfer, and therefore decreases the observed Autoprotolysis pK value. The proposed equation and the parameters calculated allow an accurate estimation of the Autoprotolysis pK value for any studied water/alcohol system.
-
Autoprotolysis in aqueous organic solvent mixtures.Water/alcohol binary systems
Analytica Chimica Acta, 1996Co-Authors: G. Fonrodona, Elisabeth Bosch, Clara Ràfols, Martí RosésAbstract:By use of a previously derived equation, the main factors that contribute to Autoprotolysis are studied for different water/ alcohol mixtures. These factors are: autoionization of water, autoionization of the alcohol, and proton transfer from water to the alcohol or from the alcohol to water. The most important factors seem to be the proton transfer from the alcohol to water, and to a much lesser degree, the autoionization of water. The autoionization of the alcohol is only significant for pure alcohol. The different factors have been correlated with the solvent properties polarity and hydrogen-bond ability. An increase in these solvent properties favours autoionization and proton transfer, and therefore decreases the observed Autoprotolysis pK value. The proposed equation and the parameters calculated allow an accurate estimation of the Autoprotolysis pK value for any studied water/alcohol system.
-
Autoprotolysis in aqueous organic solvent mixtures. Water-amide and water-amine binary systems
Analytica Chimica Acta, 1995Co-Authors: Clara Ràfols, Elisabeth Bosch, Martí Rosés, Agustin G. AsueroAbstract:Abstract The contribution of the autoionization of water and organic solvent, and the proton transfer between them to the overall Autoprotolysis of mixtures of water with amides ( N , N -dimethylacetamide, N -methylacetamide, acetamide, N , N -dimethylformamide, N -methylformamide and formamide) and with amines (butylamine, N , N -diethylaminoethanol and ethanolamine) is studied and compared. Proton transfer from water to the more basic amide, and specially amine, produces the Autoprotolysis in the intermediate solvent compositions and predominates over a wide range of solvent compositions. Autoionization of water predominates only for very low amide or amine contents. Autoionization of the amide or the amine can be important at intermediate and high organic solvent compositions if the pure amide or amine has a high Autoprotolysis constant (p K ap value lower than that of pure water). Because of the higher basicity of amines over amides, proton transfer from water to the amine produces very high Autoprotolysis constants for water-amine mixtures.
Clara Ràfols - One of the best experts on this subject based on the ideXlab platform.
-
Autoprotolysis in aqueous organic solvent mixtures. Water/dipolar protophilic solvent binary systems
Analytica Chimica Acta, 1997Co-Authors: Elisabeth Bosch, G. Fonrodona, Clara Ràfols, Martí RosésAbstract:Abstract The Autoprotolysis of binary aqueous mixtures of dimethyl sulfoxide, acetonitrile, acetone, tetrahydrofuran and 1,4-dioxan is studied. It is demonstrated that except for solvent mixtures very rich in water, the Autoprotolysis is produced by proton transfer from water to the dipolar organic solvent. Only in water rich mixtures the autoionization of water contributes appreciably to Autoprotolysis. It is also suggested that the so-called Autoprotolysis constant or ionic product of these pure organic solvents is in fact, produced by proton transfer from the very small amounts of water present in the medium to the organic solvent. Equations and parameters are presented that allow calculation of the Autoprotolysis constant for any solvent composition at 25 °C. The variation of the Autoprotolysis constant with temperature is also studied for dimethyl sulfoxide/water and acetone/water mixtures.
-
Autoprotolysis in aqueous organic solvent mixtures water dipolar protophilic solvent binary systems
Analytica Chimica Acta, 1997Co-Authors: Elisabeth Bosch, G. Fonrodona, Clara Ràfols, Martí RosésAbstract:Abstract The Autoprotolysis of binary aqueous mixtures of dimethyl sulfoxide, acetonitrile, acetone, tetrahydrofuran and 1,4-dioxan is studied. It is demonstrated that except for solvent mixtures very rich in water, the Autoprotolysis is produced by proton transfer from water to the dipolar organic solvent. Only in water rich mixtures the autoionization of water contributes appreciably to Autoprotolysis. It is also suggested that the so-called Autoprotolysis constant or ionic product of these pure organic solvents is in fact, produced by proton transfer from the very small amounts of water present in the medium to the organic solvent. Equations and parameters are presented that allow calculation of the Autoprotolysis constant for any solvent composition at 25 °C. The variation of the Autoprotolysis constant with temperature is also studied for dimethyl sulfoxide/water and acetone/water mixtures.
-
Autoprotolysis in aqueous organic solvent mixtures water alcohol binary systems
Analytica Chimica Acta, 1996Co-Authors: G. Fonrodona, Elisabeth Bosch, Clara Ràfols, Martí RosésAbstract:By use of a previously derived equation, the main factors that contribute to Autoprotolysis are studied for different water/ alcohol mixtures. These factors are: autoionization of water, autoionization of the alcohol, and proton transfer from water to the alcohol or from the alcohol to water. The most important factors seem to be the proton transfer from the alcohol to water, and to a much lesser degree, the autoionization of water. The autoionization of the alcohol is only significant for pure alcohol. The different factors have been correlated with the solvent properties polarity and hydrogen-bond ability. An increase in these solvent properties favours autoionization and proton transfer, and therefore decreases the observed Autoprotolysis pK value. The proposed equation and the parameters calculated allow an accurate estimation of the Autoprotolysis pK value for any studied water/alcohol system.
-
Autoprotolysis in aqueous organic solvent mixtures.Water/alcohol binary systems
Analytica Chimica Acta, 1996Co-Authors: G. Fonrodona, Elisabeth Bosch, Clara Ràfols, Martí RosésAbstract:By use of a previously derived equation, the main factors that contribute to Autoprotolysis are studied for different water/ alcohol mixtures. These factors are: autoionization of water, autoionization of the alcohol, and proton transfer from water to the alcohol or from the alcohol to water. The most important factors seem to be the proton transfer from the alcohol to water, and to a much lesser degree, the autoionization of water. The autoionization of the alcohol is only significant for pure alcohol. The different factors have been correlated with the solvent properties polarity and hydrogen-bond ability. An increase in these solvent properties favours autoionization and proton transfer, and therefore decreases the observed Autoprotolysis pK value. The proposed equation and the parameters calculated allow an accurate estimation of the Autoprotolysis pK value for any studied water/alcohol system.
-
Autoprotolysis in aqueous organic solvent mixtures. Water-amide and water-amine binary systems
Analytica Chimica Acta, 1995Co-Authors: Clara Ràfols, Elisabeth Bosch, Martí Rosés, Agustin G. AsueroAbstract:Abstract The contribution of the autoionization of water and organic solvent, and the proton transfer between them to the overall Autoprotolysis of mixtures of water with amides ( N , N -dimethylacetamide, N -methylacetamide, acetamide, N , N -dimethylformamide, N -methylformamide and formamide) and with amines (butylamine, N , N -diethylaminoethanol and ethanolamine) is studied and compared. Proton transfer from water to the more basic amide, and specially amine, produces the Autoprotolysis in the intermediate solvent compositions and predominates over a wide range of solvent compositions. Autoionization of water predominates only for very low amide or amine contents. Autoionization of the amide or the amine can be important at intermediate and high organic solvent compositions if the pure amide or amine has a high Autoprotolysis constant (p K ap value lower than that of pure water). Because of the higher basicity of amines over amides, proton transfer from water to the amine produces very high Autoprotolysis constants for water-amine mixtures.
Mireille Turmine - One of the best experts on this subject based on the ideXlab platform.
-
application of the bahe s pseudolattice theory to water 1 butyl 3 methylimidazolium tetrafluoroborate bmimbf4 mixtures at 298 15 k part i Autoprotolysis constants
Talanta, 2007Co-Authors: Bou I Malham, Pierre Letellier, Mireille TurmineAbstract:Abstract The Autoprotolysis constants ( K s ) of water – 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF 4 ) mixtures were determined at 298 K over the composition range of 0 to 77.43 vol.% bmimBF 4 using potentiometric method with a glass electrode. A slight increase in the Autoprotolysis constant was observed when the salt was added to the water. The value of the ionic product of the medium then decreases as the bmimBF 4 content increases from about 20 vol.%. The acid–base properties of these media were perfectly described by Bahe's approaches that were completed by Varela et al. concerning structured electrolyte solutions with large short-range interactions.
-
Application of the Bahe's pseudolattice-theory to water—1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) mixtures at 298.15 K: Part I. Autoprotolysis constants
Talanta, 2006Co-Authors: I. Bou Malham, Pierre Letellier, Mireille TurmineAbstract:Abstract The Autoprotolysis constants ( K s ) of water – 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF 4 ) mixtures were determined at 298 K over the composition range of 0 to 77.43 vol.% bmimBF 4 using potentiometric method with a glass electrode. A slight increase in the Autoprotolysis constant was observed when the salt was added to the water. The value of the ionic product of the medium then decreases as the bmimBF 4 content increases from about 20 vol.%. The acid–base properties of these media were perfectly described by Bahe's approaches that were completed by Varela et al. concerning structured electrolyte solutions with large short-range interactions.