Acidity in Mixed Solvents

Gibbs energies of transfer of the proton from water into mixtures of water with chain multiple ethers: Equilibria involving changes of solvation of the proton

“…6 The influence of solvent structure on DG o t (H + ) All our measurements for alcohols are restricted to the region x 2 . x 2 for the extremum found in both H o 11,12 and in the conductivity 13,14 of water + alcohol mixtures, discussed earlier. Two indicators for structure formation at low x 2 are a positive structural contribution to the temperature of maximum density, DT ST , 35 and a minimum in the relative partial molar volume of the co-solvent, V ¯2 À V o 2 .…”

“…For a total added concentration of B ¼ c o , the actual concentration of B found in the mixture, c x , for a range of [HCl] at a fixed total concentration of S ¼ [S] T should vary as in eqn. ( 5), [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][20][21][22] g i ! 1.0 at S[i] !…”

“…3,4 This change results in an extremum in the Hammett acidity function H 0 at low x 2 for S ¼ alcohols, an ether or ketone mixed with water. 11,12 Similarly, a minimum is found in the conductivity of protons from HC1 at low x 2 . 13,14 All our investigations are restricted to the region where x 2 .…”

Ion selective electrodes, potentiometry, and potentiometric titrations

“…Acidity via H2 electrode has been studied in pentamethylphosphonic diamide (652), sulfolane (219), methanol-H20 (113) methanol-acetonitrile (113), ethanol-H20 (367), 1-propanol water (995), propylene carbonate-H20 (990), formic acid (20), amyl alcohol (114), trifluoroacetic acid (905), dioxane-water (813, 814), acetic acid (21), pyrrolidone (499), formamide (832), and Nmethylpyrrolidone (280). Acidity in isopropanol-and ethylene glycol-water (Hammett acidity) (1167), buffer pH in the same mixture (23), activity coefficients of NaOH and pH corrections in dioxane-water (1062,1255), dissociation of KC1 in ethanol-water (541), effects of salts on acidbase titrations in nonaqueous solvents (372,688,1085), activity coefficients of divalent metal perchlorates in acetonitrile (662), acid-base equilibria in dioxane-water (1178), in acetic acid-chlorohydrocarbons (574), in alcoholand THF-water (1252), and in formamide (248) have been reported. Electrode potentials for several electrodes of the zeroeth, first, and second (reference electrodes) kinds are summarized in Table VI.…”

Titrations in nonaqueous solvents

“…The ionization of a series of nitroaniline indicators in BF3 solutions of ethyl alcohol has been studied to establish the Hammett acidity function Hq in this system (45). Acidity functions in methanol-water (299,311), isopropanol-water (300), ethylene glycol-water (138,300), ethanol-water (164,299), n-propanol-water (299), methanol-dimethylsulfoxide (67), and for solutions of sodium glycoxide in ethylene glycol (9) have been established. A series of new internal indicators for determining primary aromatic amines is available (84).…”