TITRATIONS IN NONAQUEOUS MEDIA - CONDUCTIMETRIC AND SPECTROPHOTOMETRIC INVESTIGATION OF REACTIONS BETWEEN IODINE AND ALIPHATIC-AMINES IN ACETONITRILE

The reactions between iodine and methyl-, ethyl-, n-propyl- and n-butylamines were investigated conductimetrically and spectrophotometrically in acetonitrile. The mole ratios of iodine to the amines titrated are 1:2, 2:2, 3:2 and 4:2, respectively, indicating strongly the formation of anionic species of the types I-, I-3(-), I-5(-) and I-7(-) and cationic species of the type [R(3)N-I-NR(3)](+). Although the conductivities of the primary amines do not show a regular order, the secondary and tertiary amines show orders at least at the first end-points. The order for secondary amines is Me(2)NH>Et(2)NH>n-Pr2NH>n-Bu(2)NH and for tertiary amines n-Bu(3)N>n-Pr3N>Et(3)N>Me(3)N. The endpoints of the conductimetric titrations are fairly sharp and can be used in the determination of these amines.