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  • 1
    Electronic Resource
    Electronic Resource
    Conductance of tetraalkylammonium salts in propylene carbonate at 25°C (1978)
    Springer
    Journal of solution chemistry 7 (1978), S. 631-638 
    Details
    ISSN: 1572-8927
    Keywords: Association of ions ; conductivity ; dissociation ; ionization ; ion pairing ; nonaqueous solvents ; propylene carbonate ; solute-solvent effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Conductance measurements of 12 quaternary ammonium salts in propylene carbonate (PC) have been made at 25°C. The cations were either tetramethylammonium, tetraethylammonium, or tetra-n-butylammonium, and the concentrations of salt varied from about 2×10−4 to 5×10−3 M. The data were analyzed by the equation of Pitts. The results showed that the benzoate, nitrobenzoate, and pentachlorophenolate salts are completely dissociated. The nitrophenolate, chlorophenolate, methylsulfonate, and nitrate salts are only slightly associated (K A from 2.5 to 6.5), while the acetate, phenylacetate, and nitrophenolate salts display somewhat more extensive association, with ionpair association constants from 17 to 45. Limiting molar conductances for the anions were derived. The factors affecting ionic mobilities in this dipolar aprotic solvent are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00646040
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Solute-solvent effects in the acidic dissociation of the ampholyte N-tris(hydroxymethyl)methylglycine (“tricine”) in 50 mass % methanol-water solvent (1974)
    Springer
    Journal of solution chemistry 3 (1974), S. 905-916 
    Details
    ISSN: 1572-8927
    Keywords: Acidic dissociation ; ampholyte dissociation ; dissociation constants ; ionization ; methanol-water solvents ; solute-solvent effects ; N-Tris(hydroxymethyl)methylglycine (“tricine”) ; zwitterions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pK values for the two acidic dissociation steps of the ampholyte N-tris-(hydroxymethyl)methylglycine (“tricine”) in 50 mass % methanol-water solvent have been determined by emf measurements of cells of the type Pt|H2(g, 1 atm), tricine buffer, Br−, AgBr|Ag over the range 5 to 50°C (pK 1)and 5 to 60°C (pK 2).The standard thermodynamic quantities ΔHo, ΔSo, and ΔC p o for the two dissociation processes have been derived and are compared with the corresponding values for tricine and the parent glycine in water and with those for other acids in 50 mass % methanol-water solvent. Both tricine and protonated tricine become weaker acids when methanol is added to the aqueous solvent. It appears that a strong stabilization of the zwitterion in water is responsible for this behavior. This conclusion is supported by comparing the changes in entropy and heat capacity for the dissociation of tricine with the values of these quantities for the dissociation of “model” acids of simple structure, such as ammonium ion and acetic acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00647944
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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