Akademik Veri Yönetim Sistemi
The Analyst, cilt.3, ss.1345-1347, 1986 (SCI-Expanded)
The relative basicity orders of methyl-, ethyl-, propyl- and butylamines have been measured potentiometrically with perchloric acid in cyclohexane and hexane solvents. The basicity orders of the amines in the series, including ammonia, were found to be NH3 MeNH2 Me2NH > Me3N; NH3 EtNH2 Et2NH > Et 3N; NH3 n-PrNH2 n-Pr2NH > n-Pr3N; NH3 n-BuNH2 n-Bu2NH > n-Bu3N; and n-BuNH2 /-BuNH2 sec-BuNH 2 t-BuNH2. In addition to these, some interesting orders have also been found among primary, secondary and tertiary amines, e.g., MeNH2 EtNH2 n-PrNH2 n-BuNH2; Me 2NH > Et2NH > n-Pr2NH > n-Bu 2NH; Me3N Et3N n-Pr3N n-Bu 3N; and MeNH2 EtNH2 i-PrNH2 t-BuNH2. From these findings four important results have been obtained as follows: (1 ) an increase in the number of alkyl group decreases the basicity; (2) an increase in the size of an alkyl group decreases the basicity; (3) amines containing unbranched alkyl groups are more basic than their branched analogues; and (4) an increase in the number of methyl substituents on the methyl group of methylamine decreases the basicity in a regular manner. These results contradict results reported in the literature and also earlier results obtained in this laboratory.