Effects of temperature and solvent composition on conductometric titrations in nonaqueous mixed solvents

1988 ◽  
Vol 60 (21) ◽  
pp. 2358-2364 ◽  
Author(s):  
Giancarlo. Franchini ◽  
Carlo. Preti ◽  
Lorenzo. Tassi ◽  
Giuseppe. Tosi
1989 ◽  
Vol 61 (2) ◽  
pp. 177-184 ◽  
Author(s):  
Giancarlo. Franchini ◽  
Andrea. Marchetti ◽  
Carlo. Preti ◽  
Lorenzo. Tassi ◽  
Giuseppe. Tosi

1945 ◽  
Vol 18 (4) ◽  
pp. 790-802
Author(s):  
Elizabeth M. Frith

Abstract The general problem of plasticizer compatibility is discussed, and it is suggested that a comparative measure of compatibility can be obtained from experiments which measure polymer-plasticizer interactions (w). Experiments are described which measure the viscosity of dilute polymer solutions in suitable mixed solvents containing the plasticizer in question. The slope of the ηsp/c−c curve is shown to be related to the equilibrium extent of swelling of the polymer in the pure plasticizer and, in general, the slope of the curve is a good comparative measure of the plasticizer's compatibility. The effects of temperature and composition of the mixed solvent are also discussed. The experiments are considered in the light of a previous theory of the effect of solvent on the ηsp/c ratio: the results do not support the suggested view that the slope of the ηsp/c−c curve is a simple linear function of w/kT.


Polymer ◽  
1995 ◽  
Vol 36 (12) ◽  
pp. 2443-2449 ◽  
Author(s):  
Tomoo Shiomi ◽  
Katsuhito Kuroki ◽  
Akira Kobayashi ◽  
Hiroki Nikaido ◽  
Masaharu Yokoyama ◽  
...  

1979 ◽  
Vol 57 (18) ◽  
pp. 2470-2475 ◽  
Author(s):  
Kumardev Bose ◽  
Kiron K. Kundu

The autoprotolysis constants (Ksm) of ethylene glycol in isodielectric acetonitrile + ethylene glycol mixtures have been determined at 25 °C from emf measurements on the cell[Formula: see text]From these values, those of δΔG0, the free energy of ionization of ethylene glycol in these mixed solvents relative to that in pure glycol, have been computed. The nature of variation of δΔG0 with solvent composition has been compared with that in two other mixed systems: water + ethylene glycol and methanol + 1,2-propanediol and the intrinsic differences between the solvation characteristics of the various solvents have been pointed out. The standard free energies of transfer of the glycoxide ion, ΔGt0(OEg−), from pure glycol to acetonitrile + glycol mixtures have also been estimated using ΔGt0(H+) values obtained earlier. The glycoxide ion is increasingly desolvated as the acetonitrile content of the solvent increases, as indicated by increasingly positive values of ΔGt0(OEg−). This behaviour has been compared with those of ΔGt0(H+) and ΔGt0(Cl−) determined previously.


1976 ◽  
Vol 54 (5) ◽  
pp. 706-710 ◽  
Author(s):  
James P. K. Tong ◽  
Cooper H. Langford

The rates of nickel(II)–murexide complex formation were studied in dimethylsulfoxide/nitromethane mixed solvents at 25 °C with the latter being an "inert" solvent, to elucidate the mechanism of the reaction. Results do not fit in detail with a D mechanism and the five-coordinated intermediate interpretation. Id mechanisms are able to explain the observations with and without invoking a nitromethane-containing intermediate, Ni(DMSO)5NM2+. Both mechanisms were tested with the aid of nmr data on solvation (second coordinate sphere nitromethane population). Ligand solvation unavoidably plays a major role in the determination of the encounter as well as the complex formation equilibrium. The simplest mechanism assumes an Id process in which the probability of encounter between Ni(DMSO)62+ and murexide ion is quite sensitive to solvent composition.


1971 ◽  
Vol 26 (11) ◽  
pp. 1091-1096 ◽  
Author(s):  
James R. Bard ◽  
James O. Wear

0.01 ᴍ solutions of Mn (ClO4)2, MnCl2 and MnSO4 in water-methanol mixtures were studied at 25 °C to determine the effect of these anions and of solvent composition on the ESR intensity and linewidth of Mn(II). A significant feature of the data was the large difference between the intensity of Mn(ClO4)2 and that for MnCl2 and MnSO4 in solutions containing greater than about 0.5 mole fraction methanol. A plot of linewidth versus mole fraction methanol shows little difference between Mn(ClO4)2 and MnCl2 but an increasingly greater difference between these salts and MnSO4 with increasing methanol content. These results are interpreted as being due to first coordination sphere complex formation in solutions containing Cl⊖, while the SO42⊖ data are affected by both first and second coordination sphere complexes depending upon the solvent dielectric constant. The Mn(ClO4)2 data were interpreted as showing that the primary solvation sphere of the Mn(II) ions was changing as the composition of the bulk solvent changed. These results are compared with similar data in aqueous solution and confirm that complex formation involving Cl⊖ or SO42⊖ ions and Mn(II) is extensive in water-methanol mixtures.


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