This research investigates the CO2 corrosion inhibition characteristics of a synthesized pyrimidine derivative whose molecular structure is embellished with nitrogen-based functional groups with the intention of achieving highly effective and stable film formation, at low doses, after prolonged corrosion period under turbulent hydrodynamics. For this purpose, 5-(4-(dimethylamino)phenyl)-2,7-dithioxo-2,3,5,6,7,8-hexahydropyrimido[4,5-d]pyrimidin-4(1H)-one (DPP) was synthesized using the one-pot method, and investigated as inhibitor against the corrosion of API X60 steel after instantaneous and prolonged (72 h) immersion in CO2-saturated NACE ID196 brine under 10 0 0 rpm rotation speed. Results from potentio-dynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) measurements show that DPP is a mixed-type inhibitor which lowers the double layer capacitance and rate of charge transfer across the steel-solution interface with 97% efficiency. Its instantaneous adsorption blocks the steel sur-face from any noticeable microstructural damage, based on scanning electron microscopy (SEM) charac-terization. After prolonged exposure (72 h), the uninhibited steel experiences enhanced resistance, which inversely depreciated the DPP efficiency to > 73%. With DPP, however, the steel is significantly protected against surface microstructural degradation, based on SEM assessment. Computational modeling with density functional theory (DFT) and molecular dynamics simulation (MDS) provided molecular-level confirmation of the experimental results.(c) 2023 Elsevier B.V. All rights reserved.
