Organic Inhibitors of Corrosion

Abstract

A theory is presented which explains the mechanism of inhibitor action for organic inhibitors in the acid corrosion of steel. Organic inhibitors containing nitrogen, oxygen or sulfur are considered. Aliphatic amines, aromatic amines and heterocyclic nitrogen‐containing compounds, the ketones both aliphatic and aromatic, and a sulfur‐containing inhibitor were investigated. All of these form the onium compounds which ionize readily. The length, the number, and the position of aliphatic radicals on rings and particularly their stereochemical arrangement determines the effectiveness of inhibition as well as the quantity of inhibitor required for good protection. Solubility and the resulting increasing ionization is a requisite for good inhibiting action.