The Corrosion Inhibition Performance and Synergistic Adsorption Mechanism of a Novel Quinoline-Based Inhibitor for J55 Steel in HCl Solution

Novel and high-efficiency corrosion inhibitors are indispensable in acidizing stimulation, which is a key operation to increase oil production. In this study, a novel corrosion inhibitor, alkynyl bisquinolinium quaternary ammonium salt (ABQ) containing both a quinoline ring and alkynyl groups, was first developed through a quaternization reaction using quinoline and 1,4-dichlorobutyne. ABQ was then compounded with 3-phenyl-2-propyn-1-ol (PPA). ABQ-PPA’s corrosion inhibition performance and mechanism for J55 steel in a hydrochloric acid medium were systematically investigated through static weight-loss tests, electrochemical measurements, SEM characterization, thermodynamic adsorption analysis, and molecular dynamics (MD) simulations. The results indicated that the 0.5% ABQ-PPA mixture (0.45% ABQ and 0.05% PPA, mass ratio 4.5: 0.5) produced superior inhibition properties (up to 99.89%). Electrochemical measurements demonstrated that the ABQ-PPA complex could simultaneously suppress both anodic and cathodic reactions, acting as a mixed-type inhibitor with predominant anodic inhibition. Adsorption isotherm analysis revealed that ABQ-PPA’s adsorption onto the J55 steel surface followed the Langmuir monolayer adsorption model, with a mixed adsorption mode involving both physisorption and chemisorption. Molecular dynamics simulations further revealed that ABQ-PPA molecules formed a compact and orderly mixed adsorption layer on the Fe surface, displacing interfacial water molecules and blocking corrosion attack from corrosive media.