Adsorption of long-chain aliphatic amines-components of corrosion inhibitors

Adsorption of certain long-chain aliphatic amines with 6–18 carbon atoms is studied on a stationary mercury drop electrode using the impedance method. It is found that adsorption of amines with C6–C12 results in the formation of an adsorption layer with the limiting capacitance of about 5 μF/cm2. In the case of amines with C14–C16, the limiting capacitance is approximately 0.5–0.7 μF/cm2. The most probable reason for such abrupt decrease in the adsorption layer capacitance is the formation of condensed layers of adsorbate molecules at the electrode surface. The adsorption parameters are calculated for hexylamine. The surface activity is estimated for amines with 10–14 carbon atoms in their chains.