Hydroquinone Decorated with Alkyne, Quaternary Ammonium, and Hydrophobic Motifs to Mitigate Corrosion of X‐60 Mild Steel in 15 wt.% HCl.

1‐(6‐Bromohexyloxy)‐4‐propargyloxybenzene upon quaternization with 3‐dimethylamino‐1‐propanol and N,N‐dimethyldodecylamine produced two new inhibitor molecules: N‐[6‐(4‐Propargyloxyphenoxy)hexyl]‐N,N‐dimethyl‐N‐(3‐hydroxypropyl)ammonium bromide (PHAB) and N‐[6‐(4‐Propargyloxyphenoxy)hexyl]‐N,N‐dimethyl‐N‐dodecylammonium bromide (PDAB), respectively, in excellent yields. The inhibitor molecules were characterized by elemental analysis, Fourier transform infrared spectroscopy, 1H NMR, and 13C NMR spectroscopy. The inhibitors were evaluated for X‐60 mild steel corrosion in 15 wt.% HCl using different electrochemical and gravimetric techniques. The potentiodynamic polarization confirms both the inhibitors as mixed‐type corrosion inhibitors. A low concentration (15 ppm) of PDAB has demonstrated excellent corrosion inhibition efficiencies of 97%, 98%, and 86% at 25 °C, 50 °C, and 70 °C, respectively, for 24 h exposure time. SEM and EDX spectra reveal that the adsorptions of corrosion inhibitors on X‐60 mild steel create a protective film that serves as a barrier to mitigate the corrosion process. The X‐ray photoelectron spectroscopy confirmed the chemical interaction between the corrosion inhibitors and mild steel, which was predicted by the Langmuir adsorption model. Assembly of inhibitive motifs of the alkyne, π‐electron‐rich aromatic, quaternary ammonium and C12 alkyl chain hydrophobe in PDAB has augmented its inhibiting action. [ABSTRACT FROM AUTHOR]