| The internal corrosion of pipelines is a major cost for the oil and gas industry, because most of the production facilities are subject to corrosion by water, which is enhanced by the presence of CO2 and H2S in the gas phase. A large portion of the cost for internal pipelines corrosion is for corrosion inhibitors. The commonly used film-forming corrosion inhibitors are imidazolines and their amidoamines precursors.;In this thesis, nine different amidoamines and three of their corresponding imidazolines were successfully synthesized by the reaction of polyamines with fatty acids or fatty nitriles of different chain lengths. The structures of these compounds were confirmed by their NMR and IR spectra. The corrosion inhibition efficiencies of the inhibitors were determined by polarization resistance and Tafel plots. The imidazolines showed very good inhibition as compared to their corresponding amidoamine precursors.;The value of the enthalpy of adsorption, DeltaHads, suggests that the adsorption of the imidazolines is of the physisorption type. This was attributed to the weak counter anion CO32- and the nature of the adsorption process which involves the desorption of CO 2 and water molecules from the metal surface. Surface tension studies showed that the structure of the inhibitor affects its solubility and micellization, which in turn affects its adsorption and inhibition efficiency. |
