Coordinating Properties of Aromatic and Aliphatic Sulfur with Bivalent Metals in Aqueous Solution. A Calorimetric Study

1979 ◽  
Vol 32 (4) ◽  
pp. 709 ◽  
Author(s):  
R Aruga
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Complex Formation ◽  
Aqueous Medium ◽  
Formation Constants ◽  
Calorimetric Study ◽  
Thermodynamic Quantities ◽  
Direct Calorimetry ◽  
Bivalent Metals

Heats and entropies of complex formation of the thiophen-2-carboxylate ion with Ni2+, Cu2+, Zn2+ and Cd2+ have been determined by direct calorimetry, the formation constants being known from the literature. The measurements were carried out in aqueous medium at 25�C and an ionic strength of 1. The values of the thermodynamic quantities for thiophen-2-carboxylate, compared with those for (ethylthio)acetate and (phenylthio)acetate obtained previously, indicate a greater tendency for aromatic sulfur to form bonds with the above metals than for aliphatic sulfur. The causes of this behaviour are discussed.

Complex formation and solubility of Pu(IV) with malonic and succinic acids

2009 ◽  
Vol 97 (4-5) ◽  
Author(s):  
Takayuki Sasaki ◽  
Taishi Kobayashi ◽  
I. Takagi ◽  
Hirotake Moriyama ◽  
A. Fujiwara ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Solvent Extraction ◽  
Complex Formation ◽  
Extraction Method ◽  
Formation Constants ◽  
Complex Formation Constants ◽  
Solvent Extraction Method ◽  
Experimental Solubility Data ◽  
Experimental Solubility ◽  
Solubility Products

AbstractThe complex formation constants of tetravalent plutonium ion with malonic and succinic acids in aqueous solution were determined by the solvent-extraction method. Also, by taking the known values of the solubility products, the hydrolysis constants and the formation constants, the experimental solubility data of plutonium in the presence of carboxylates were analyzed.

Formation et stabilité de complexes hydroxo–ammonio en solution aqueuse. I. Complexes de zinc

1968 ◽  
Vol 46 (10) ◽  
pp. 1707-1714 ◽  
Author(s):  
A. O. Gubeli ◽  
J. Ste-Marie
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Formation Constants ◽  
New Method ◽  
Hydroxo Complexes ◽  
Solution Aqueuse

A new method has been developed for the calculation of the formation constants of complexes in equilibrium with a precipitate in aqueous solution. This has been applied to the study of ammonio and ammonio–hydroxo complexes of zinc in the presence of the hydroxide. The curves of solubility vs. pH and pNH3 tot have been established by means of 65Zn at 25 °C and ionic strength 1.0 with NaClO4.

scholarly journals Understanding the Solution Behavior of Epinephrine in the Presence of Toxic Cations: A Thermodynamic Investigation in Different Experimental Conditions

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 511 ◽  
Author(s):  
Francesco Crea ◽  
Concetta De Stefano ◽  
Anna Irto ◽  
Gabriele Lando ◽  
Stefano Materazzi ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Complex Formation ◽  
Formation Constants ◽  
Titration Calorimetry ◽  
Interaction Theory ◽  
Thermodynamic Investigation ◽  
Experimental Conditions ◽  
Complex Formation Constants ◽  
Specific Ion Interaction Theory ◽  
Enthalpy Changes

The interactions of epinephrine ((R)-(−)-3,4-dihydroxy-α-(methylaminomethyl)benzyl alcohol; Eph−) with different toxic cations (methylmercury(II): CH3Hg+; dimethyltin(IV): (CH3)2Sn2+; dioxouranium(VI): UO22+) were studied in NaClaq at different ionic strengths and at T = 298.15 K (T = 310.15 K for (CH3)2Sn2+). The enthalpy changes for the protonation of epinephrine and its complex formation with UO22+ were also determined using isoperibolic titration calorimetry: ΔHHL = −39 ± 1 kJ mol−1, ΔHH2L = −67 ± 1 kJ mol−1 (overall reaction), ΔHML = −26 ± 4 kJ mol−1, and ΔHM2L2(OH)2 = 39 ± 2 kJ mol−1. The results were that UO22+ complexation by Eph− was an entropy-driven process. The dependence on the ionic strength of protonation and the complex formation constants was modeled using the extended Debye–Hückel, specific ion interaction theory (SIT), and Pitzer approaches. The sequestering ability of adrenaline toward the investigated cations was evaluated using the calculation of pL0.5 parameters. The sequestering ability trend resulted in the following: UO22+ >> (CH3)2Sn2+ > CH3Hg+. For example, at I = 0.15 mol dm−3 and pH = 7.4 (pH = 9.5 for CH3Hg+), pL0.5 = 7.68, 5.64, and 2.40 for UO22+, (CH3)2Sn2+, and CH3Hg+, respectively. Here, the pH is with respect to ionic strength in terms of sequestration.

Synthesis of nanometric TiO2 in aqueous solution by soft chemistry: obtaining of anatase, brookite and rutile with controlled shapes

2004 ◽  
Vol 822 ◽  
Author(s):  
Magali Koelsch ◽  
Sophie Cassaignon ◽  
Jean-Pierre Jolivet
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Medium ◽  
Crystalline Structure ◽  
Soft Chemistry ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Nanometric Particles ◽  
Size And Morphology ◽  
Hcl Medium

AbstractNanometric particles of titania, exhibiting anatase, brookite or rutile polymorphs, were synthesized by thermohydrolysis of TiCl4 in aqueous medium. The adjustement of physico-chemical parameters (acidity, ionic strength, anions, temperature) allows to tune the crystalline structure, the size and the morphology of the particles. Brookite results from the precipitation of titanium in HCl, HBr or HNO3 whereas anatase is formed in H2SO4 medium. Adding salts in HCl medium leads to ionic strength or complexation effect. Varying the temperature of thermohydrolysis implies modification on yield, size and morphology of the particles.

Viscosimetric studies of chitosan nitrate and chitosan chlorhydrate in acid free NaCl aqueous solution

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Cristóbal Lárez Velásquez ◽  
Joel Sánchez Albornoz ◽  
Enrique Millán Barrios
Keyword(s):  
Aqueous Solution ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Aqueous Medium ◽  
Intrinsic Viscosity ◽  
Free Acid ◽  
Film Formation ◽  
Stiffness Parameter ◽  
Low Ionic Strength

AbstractTwo salts of the biopolymer chitosan were prepared in aqueous medium by employing an excess of HCl or HNO3 in order to ensure neutralization of all NH2-chitosan groups. Chitosan salts were extensively dialyzed in dionised water and dried at 40 ºC until film formation. The films were characterized by thermogravimetry, FTIR and conductimetric tritration. QH+Cl− and QH+NO3− salts were viscosimetrically evaluated in free acid aqueous solutions in the presence of NaCl to control ionic strength of the medium. Unexpected high intrinsic viscosity values were obtained at low ionic strength when QH+NO3− salt were evaluated. Smidsrod´s approach was employed to estimate the stiffness parameter of both salts and B = 0.084 and 0.120 for QH+Cl− and QH+NO3−, respectively, were obtained.

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