Coefficient d'activité de l'acide sulfurique déterminé par titrage infrarouge

2000 ◽  
Vol 78 (8) ◽  
pp. 1128-1142 ◽  
Author(s):  
Christophe Ménichelli ◽  
Jean-Joseph Max ◽  
Camille Chapados
Keyword(s):  
Factor Analysis ◽  
Ir Spectroscopy ◽  
Aqueous Solutions ◽  
Activity Coefficients ◽  
Total Concentration ◽  
Relative Concentration ◽  
Ionic Species ◽  
Attenuated Total Reflection ◽  
Equilibrium Equations ◽  
Ph Range

The titration of sulphuric acid by infrared spectroscopy using the attenuated total reflection (ATR) technique was made in the 0 to 14 pH range for solutions ranging from 1.89 to 0.01 M. The subtraction of the water spectrum was made using acidic, neutral, and basic waters which exhibit different spectra. The results gave the spectra of mixtures of the HSO–4 and SO2–4 ionic species in solutions. For each concentration, factor analysis (FA) sorted the spectra of the pure ionic species and gave through the multiplying factors (MF) the distribution of the species as a function of pH. This distribution is the same as that obtained from the equilibrium equations. The IR measurements gave directly the ratios of the activity coefficients of HSO–4 and SO2–4 ions. This ratio varies with the total concentration of both ions but is independent of the relative concentration. The fitting of the experimental and theoretical volumetric titration curves in the high and low pH regions gave the mean activity coefficients of the other species present in the solutions. The values obtained are comparable to those obtained by electrochemical measurements. These results show that it is possible to use IR spectroscopy to study aqueous solutions of inorganic acids from low to high concentrations.Key words : IR spectroscopy, sulfuric acid, aqueous solutions, factor analysis, ATR, principal spectra, solvation, activity coefficients, IR titration.

IR Spectroscopy of aqueous alkali halides. Factor analysis

2001 ◽  
Vol 79 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Jean-Joseph Max ◽  
Serge de Blois ◽  
Alain Veilleux ◽  
Camille Chapados
Keyword(s):  
Factor Analysis ◽  
Ir Spectroscopy ◽  
Aqueous Solutions ◽  
Pure Water ◽  
Alkali Halides ◽  
Attenuated Total Reflection ◽  
Order Effects ◽  
Solubility Range ◽  
Anions And Cations ◽  
Principal Species

The infrared spectra of ten salts in aqueous solutions were obtained in their solubility range using attenuated total reflection (ATR). The salts are: LiCl, NaCl, KCl, CsCl, MgCl2, NaBr, KBr, NaI, KI, and CsI. The salts, which are completely ionized in water, do not absorb in the IR. Only their interactions with water are observed and analyzed. Factor analysis (FA) applied to the spectra showed that two principal species are present in the solutions: pure water and salt-solvated water. The modifications of the water spectrum are dependent on the nature of the salts, their concentrations and are mainly of first-order. Second-order effects were observed but, being weak, were not investigated. The modifications of the IR-ATR spectrum from pure water to a salt solution are proportional to the modifications of the imaginary part of the refractive index spectrum (k(v)). This indicates that the anomalous dispersion effects do not interfere with the chemical analysis of the IR-ATR spectra. In every salt studied, the two main species present in the solutions remained stable throughout the salt solubility ranges. Comparison between the IR spectra of the different salts solutions indicates that both anions and cations are in strong interaction with water molecules and are solvated together in stable clusters.Key words: IR spectroscopy, ATR, liquid, aqueous solutions, factor analysis, principal spectra, LiCl, NaCl, KCl, CsCl, NaBr, KBr, NaI, KI, CsI, MgCl2.

Infrared Titration of Aqueous Glycine

1998 ◽  
Vol 52 (2) ◽  
pp. 226-233 ◽  
Author(s):  
Jean-Joseph Max ◽  
Michel Trudel ◽  
Camille Chapados
Keyword(s):  
Factor Analysis ◽  
Aqueous Solutions ◽  
Ir Spectra ◽  
Ionic Species ◽  
Ionic Distribution ◽  
Volumetric Titration ◽  
Ph Range

The infrared (IR) spectra of glycine in aqueous solutions were obtained in the pH range 0.2 to 14 in order to determine the ionic distribution of the molecule as a function of pH by factor analysis (FA). After subtraction of the water bands, FA was used to separate the spectra of each ionic species and determine their real abundance. The p Ka values were retrieved from the volumetric titration as a function of pH and were used to obtain the theoretical abundance of each ionic species as a function of pH. These distribution curves were compared with the distribution curves obtained from IR. The agreement between the two curves was good. The following species were observed for glycine in water: the cation (pH 0 to 5); the zwitterion (pH 0 to 12.5); and the anion (pH 7 to 14).

Titrage infrarouge de l'acide phosphorique

2000 ◽  
Vol 78 (4) ◽  
pp. 490-507 ◽  
Author(s):  
Jocelyn Baril ◽  
Jean-Joseph Max ◽  
Camille Chapados
Keyword(s):  
Factor Analysis ◽  
Phosphoric Acid ◽  
Distribution Curve ◽  
Equilibrium Constants ◽  
Ionic Species ◽  
Abundant Species ◽  
Residual Water ◽  
Ft Ir ◽  
Ph Range ◽  
Principal Species

The titration of phosphoric acid by sodium hydroxide was performed by infrared (IR) spectroscopy with the objective of obtaining the infrared spectra of the pure ionic species and determining their abundance as a function of pH. In the series of spectra, taken in the pH range of 0.18-13.4, the subtraction of neutral water, acidic water, and basic water was made. Factor analysis (FA) was then applied to the series of spectra to obtain the objective. First, we found the four most abundant species : H3PO4 (pH 0-4), H2PO-4 (pH 0-9), HPO4-2 (pH 4-14), and PO4-3 (pH 9-14). Secondly, we found three complexes in small quantities : H3PO4–H2PO–4(pH 0-4),H2PO–4–HPO–24 (pH 4-9), and HPO–24–PO–34 (pH 9-14). The equilibrium constants of these species with the parent molecules are 0.65, 0.63, and 0.4 L/mol, respectively. Thirdly, we found residual water that was closely bound to the ionic species which formed hydrates. The pKa values obtained from the IR titration were used to obtain the theoretical concentration of the four principal species as a function of pH. The resulting distribution curve was found to be coincident with the distribution curve obtained by IR.Key words : infrared spectroscopy, FT-IR, aqueous solutions, factor analysis, titration, phosphoric acid, pH.

scholarly journals Kinetik und Mechanismus der Substitutionsreaktionen von Komplexverbindungen, XLVIII / Kinetics and Mechanism of the Substitution Reactions of Complexes, XLVIII

1975 ◽  
Vol 30 (5-6) ◽  
pp. 393-398 ◽  
Author(s):  
J. Zsakó ◽  
Cs. Várhelyi ◽  
Z. Finta ◽  
J. Kiss-Jakab
Keyword(s):  
Activation Energy ◽  
Aqueous Solutions ◽  
Kinetic Parameters ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Ionic Species ◽  
Protolytic Equilibrium ◽  
Substitution Reactions ◽  
Basic Solutions ◽  
Ph Range

In aqueous solutions the nonelectrolyte [Co(DH)2(NO2)(H2O)] participates in protolytic eqilibria and thus it exists in 7 different forms. Rate constants of the aquation, which leads to the substitution of the nitro group, have been measured in the pH-range between 3.72 and 8 at various temperatures. From these data rate constants, activation energies and entropy values of the aquation of 2 ionic species have been derived, as well as equilibrium constants for the protolytic equilibrium between these species. The kinetic parameters obtained have been compared to those of the aquation of the ionic species which exist in acid and basic solutions and the correlation between structure and activation energy of the aquation has been discussed.

scholarly journals Radionuclide 106Ru behavior in aqueous solutions by ion exchange, ultrafiltration, and centrifugation methods

2021 ◽  
Vol 57 (3) ◽  
pp. 331-339
Author(s):  
O. B. Korenkova ◽  
A. V. Radkevich ◽  
N. I. Voronik
Keyword(s):  
Ion Exchange ◽  
Aqueous Solutions ◽  
Waste Treatment ◽  
Membrane Separation ◽  
Liquid Radioactive Waste ◽  
Ionic Species ◽  
Species Formation ◽  
Wide Ph Range ◽  
Ph Range ◽  
Ru Species

The paper presents the results of 106Ru radionuclide behavior regularities study in aqueous solutions in a wide pH range by ultrafiltration, ion exchange and centrifugation methods. The regions of 106Ru various species existence in solution have been established: cationic 106Ru species at pH < 3.5; the transition region of non-ionic species formation in the range of pH 3.5–4.2 and the region of non-ionic species predominant formation at pH > 4.2. A characteristic feature of the studied solutions is the formation of non-ionic particles by microconcentrations of 106Ru via pseudocolloids at lower pH values as compared to ruthenium solutions with a concentration of 10-6–10-4 mol/dm3. The established regularities of the behavior of ruthenium radionuclides can be utilized to increase the efficiency of ion exchange and membrane separation methods at nuclear and radiation facilities for technological solutions and liquid radioactive waste treatment.

scholarly journals Investigations of ternary complexes of Co(II) and Ni(II) with thiodiacetate anion and 1,10-phenanthroline or 2,2’-bipyridine in aqueous solutions

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Dariusz Wyrzykowski ◽  
Joanna Pranczk ◽  
Dagmara Jacewicz ◽  
Aleksandra Tesmar ◽  
Bogusław Pilarski ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Substitution Reactions ◽  
Experimental Conditions ◽  
Kinetic Measurements ◽  
Hydroxo Complexes ◽  
Binary Complexes ◽  
Vis Spectroscopy ◽  
Potentiometric Titration Method ◽  
The Stability ◽  
Ph Range

AbstractA potentiometric titration method (PT) and a stopped-flow kinetic technique monitored by a UV−Vis spectroscopy have been used to characterize the stability of series of Co(II)- and Ni(II)-thiodiacetato complexes, M(TDA), in the presence of 1,10-phenanthroline (phen) or 2,2’-bipyridine (bipy) in aqueous solutions. The stability constants of the binary (1:1), ternary (1:1:1) as well as the resulting hydroxo complexes were evaluated and compared to the corresponding oxydiacetate complexes. Based on the species distribution as a function of pH the relative predominance of the species in the system over a pH range was discussed. Furthermore, the kinetic measurements of the substitution reactions of the aqua ligands to phen or bipy in the coordination sphere of the binary complexes M(TDA) were performed in the 288–303 K temperature range, at a constant concentration of phen or bipy and at seven different concentrations of the binary complexes (0.2–0.5 mM). The kinetic stability of the M(TDA) complexes was discussed in relation to the experimental conditions and the kind of the auxiliary ligands (phen/bipy). Moreover, the influence of the type of primary ligand (thiodiacetate/oxydiacetate) on the substitution rate of the auxiliary ligands was also compared.

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