Titrations in non-aqueous media. Part II. Basicity order of aliphatic amines in nitrobenzene solvent
- 1 January 1986
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in The Analyst
- Vol. 111 (9) , 1099-1101
- https://doi.org/10.1039/an9861101099
Abstract
The relative basicity order of methyl-, ethyl-, propyl- and butylamines has been determined potentiometrically with perchloric acid in nitrobenzene solvent and found to be R3N > R2NH > RNH2 > NH3, where R = Et, n-Pr or n-Bu. However, for the methylamines, the order is Me2NH Me3N > MeNH2 > NH3. The orders in primary, secondary and tertiary amines are EtNH2 > MeNH2 > n-PrNH2 > n-BuNH2 > NH3; Et2NH > Me2NH > n-Pr2NH > n-Bu2NH > NH3; and Et3N > n-Pr3N n-Bu3N > Me3N > NH3. These results show that, in general, an increase in the number of alkyl groups increases the basicity of the amine, and that an increase in the size of the alkyl group decreases the basicity. n-Butylamine is a stronger base than branched-chain primary butylamines.Keywords
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