Molecular modeling for inhibition of C02 corrosion of carbon steel by imidazolin self-assembly membrane

Key words:  imidazolin inhibitor  C02 corrosion  self-assembly membrane  molecular dynamics modeling, molecular mechanics

Abstract:

The forming mechanism of self-assembly membrane (SAM) of five kinds of 1 -(2-aminoethyl)-2-alkyl-imidazolin inhibitors with different alkyl chain lengths was studied by molecular dynamics modeling and molecular mechanics method. The inhibition performance for carbon steel against C02 corrosion was evaluated theoretically. The calculation results of single molecular adsorption energies，membrane cohesive energies, adsorption angles and inter-chain distances indicate that the stability of inhibitor membrane and binding strength between the membrane and metal substrate increase with the growth of alkyl chain. And when the carbon number of n-aikyl is more than 13，the inhibitor molecules could form a dense and high coverage hydrophobic membrane to prevent corrosion media in solutions diffusing to the metal surface in order to avoid or delay metal corrosion. The theoretical evaluation results of inhibition efficiencies of the five kinds of inhibitors agree well with results of corrosion experiments.