Electrochemical and molecular modelling studies of corrosion inhibition characteristics of imidazolines on 1Cr steel under sweet conditions

Organic compounds like imidazoline derivatives are commonly used as corrosion inhibitors. This study characterised the corrosion inhibition properties of two forms of imidazoline, 2-Methyl-2-imidazoline (2-MI) and 2-Phenyl-2-imidazoline (2-PI), with and without the presence of mono ethylene glycol (MEG) on steel surface under CO₂ corrosion condition. Electrochemical, surface characterisation and molecular modelling were used to study corrosion inhibition properties and underlying mechanisms. In the pure form, 2-PI had higher corrosion inhibition efficiency than 2-MI, likely due to stronger adsorption to the steel surface, as confirmed by molecular modelling. The addition of MEG improved the inhibitor efficiency of both 2-MI and 2-PI.