The Protonation Constants of Some Aliphatic Alkylamines in ethanol-water Mixtures

Authors: ESMA KILIÇ, GÜLTEKİN GÖKÇE, ESİN CANEL

Abstract: Protonation constants of methyl-, ethyl-, propyl- and butylamines Were determined potentiometrically using an electrode system calibrated in concentration units of hydrogen ion in ethanol-water mixtures (10\% -80\% ethanol, v/v) at an ionic strength of 0.1 and at 25°C. The trend in the values of protonation constants of these aliphatic amines was explained in terms of the number of alkyl groups and solvent composition. The basicity orders were found to be NH_{3} < R_{3}N < RNH_{2} < R_{2}NH (R:-CH_{3}, -C_{2}H_{5}, -n-C_{3}H_{7} and --n-C_{4}H_{9}) in all the solvent mixtures studied.

Keywords: Aliphatic amines, potentiometry, protonation constant, ethanol-water mixtures.

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