Substitution Of Salts Research Articles

Electrochemical behaviour of β-halogenopropionitriles

The behaviour of iodo- and bromopropionitrile on a dropping mercury electrode has been investigated (chloropropionitrile is not reduced in the accessible potential range). In contrast to halogen derivatives previously studied, iodopropionitrile forms two one-electron waves at potentials of ca −1·2 and −1·5 V. With a rise in the concentration of the depolarizer, the difference between the half-wave potentials of the first and second waves increases. The shift in the second wave towards more negative potentials is accounted for by a faster increase in the rate of dimerization of the radicals compared to that of their reduction, as well as by the inhibiting effect of the dimerization product upon the latter process. An equation has been deduced from the experimental data for the current at the beginning of the first wave, i = kC 0 p exp [− αϕ F RT ], where p = 1·4–1·7 and α = 0·28–0·33. The half-wave potential of the first wave is shifted in the positive direction with increase in the concentration of iodopropionitrile. Bromopropionitrile is reduced at potentials of ca −1·8–2·0 V, forming one two-electron wave, the slope of which corresponds to α = 0·3. The half-wave potentials of the first wave of iodopropionitryl and of the bromopropionitryl wave depend in equal measure upon the concentration of the supporting electrolyte (Δϕ 1/2 ≈ 0·059 log c = Δψ 1 in the case of a 1·1 electrolyte). In both cases, the substitution of potassium or caesium salts for those of lithium (or sodium) results in a shift in the half-wave potentials in the positive direction, but in the case of iodopropionitrile, the shifts are not so great. The influence of the nature of cations of the supporting electrolyte can be explained by the specific adsorption of cations, which increases with a rising negative surface charge.

The Electrodeposition of Tin-Cadmium Alloys from Stannate-Cyanide Solutions

Smooth adherent deposits of tin-cadmium alloys can be obtained from hot solutions of sodium stannate, cadmium cyanide, sodium cyanide and sodium hydroxide. Substitution of potassium salts for sodiu...

418. Mechanism of elimination reactions. Part VIII. Temperature effects on rates and product-proportions in uni- and bi-molecular substitution and elimination reactions of alkyl halides and sulphonium salts in hydroxylic solvents

418. Mechanism of elimination reactions. Part VIII. Temperature effects on rates and product-proportions in uni- and bi-molecular substitution and elimination reactions of alkyl halides and sulphonium salts in hydroxylic solvents

417. Mechanism of elimination reactions. Part VII. Solvent effects on rates and product-proportions in uni- and bi-molecular substitution and elimination reactions of alkyl halides and sulphonium salts in hydroxylic solvents

417. Mechanism of elimination reactions. Part VII. Solvent effects on rates and product-proportions in uni- and bi-molecular substitution and elimination reactions of alkyl halides and sulphonium salts in hydroxylic solvents

XLI.—The nature of the alternating effect in carbon chains. Part XI. Further evidence on the substitution of benzylamine salts

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