Dipole moments and molecular association of some picrates of primary, secondary, and tertiary amines in benzene and dioxane

Abstract

The dielectric constants of dilute benzene and dioxane solutions of primary, secondary, and tertiary amine salts of picric acid were measured. Dipole moments are reported for the picrates of the following amines; in benzene: tri-wo-amyl-(11.9), tri-n-butyl-(11.9), triethyl(11.7), diethylbenzyl(11.8), di-n-butyl(11.5), di-w-propyl(11.5); in dioxane: tri-n-butyl(12.2), di-n-butyl(12.1), n-octyl(12.1), and rc-octadecyl(12.3). The picrates of primary and secondary amines show a pronounced tendenc} to associate in benzene, as evidenced by the nonlinear variation in dielectric constant with concentration, but not in dioxane. The effect of the size and shape of the alkylammonium ion and of hydrogen bonding on the association are discussed.