Inhibiting Behavior of Modified Polyamide on N80 Steel in CO₂ Corrosive Environment

A novel modified polyamide corrosion inhibitor was synthesized.Its corrosion inhibition property was evaluated by weight-loss method and polarization curve measurement under simulated operation conditions with CO2,and then compared with imidazoline quaternary ammonium salt.Quantum chemistry AM1 method was used to calculate the orbit energy of the hightest occupied molecular (EHOMO) and orbit energy of the lowest unoccupied molecular orbit ELUMO) of modified polyamide and imidazoline quaternary ammonium salt,and the inhibition mechanism of modified polyamide was investigated.The results showed that the modified polyamide could inhibit CO2 corrosion effectively,but it was inferior to imidazoline quaternary ammonium salt.It belongs to mixed type inhibitor which controls anodic processes principally and has coordinate bond with metal through lone pair electrons provided by many adsorption centers to protect the metal.