Influence of alkyl group of imidazolinyl-quaternary-ammonium-salt on corrosion inhibition efficiency

Abstract

The action between imidazolinyl-quaternary-ammonium-salt (IQAS) molecule and Fe atom was studied, and the influence of the alkyl group connected with N atom of imidazoline ring on corrosion inhibition efficiency was explored. Quantum chemical methods, HF/6–31 G and HF/Lan L2 dz, were applied successively to calculate the parameters such as front molecular orbit energy of IQAS I–IV and chemical adsorption for IQAS I–IV and Fe atom. The corrosion inhibition efficiency was measured with the weight loss method of carbon steel samples in acidic solution and oil field sewage. Based on the theoretical analyses and experimental results, it is concluded that N-Fe coordination bond is formed between IQAS molecule and Fe atom, corrosion inhibition efficiency is decreased in the following order (from large to small): IQAS IV, IQAS III, IQAS II, IQASI.

Keywords

imidazolinyl-quaternary-ammonium-salt / corrosion inhibition efficiency / quantum chemistry / weight loss method