Corrosion inhibition by imidazoline and imidazoline derivatives: a review

Abstract Imidazoline and imidazoline derivatives are extensively employed as effective corrosion inhibitors due to their low toxicity, low cost and environmental friendliness. Their chemical structure consists of a 5-membered heterocyclic ring (C 3 N 2 H 4 ) with two nitrogen atoms that are readily adsorbed onto metal surfaces. Also, a pendant side chain or alkyl amine substituent acts as an anchor that helps to maintain its adsorption on steel surfaces. The tail portion is a long hydrocarbon chain that can form a hydrophobic film on a surface. These molecular structures make it very attractive as a starting point for several enhancements in corrosion inhibition research. Moreover, modification of an imidazoline structure can be more effective in enhancing its effectiveness in corrosion inhibition. This review compiled all information regarding imidazoline and imidazoline derivatives used as effective corrosion inhibitors in the petroleum industry. It includes their chemical structures and properties, synthesis processes, characterisation and performance evaluations. The review also gives an overview of various types of imidazoline inhibitors with their preparation processes, metal types, corrosive media and concentration range for measurements.