Corrosion Inhibition of Mild Steel by Cetrimoniumtrans-4-Hydroxy Cinnamate: Entrapment and Delivery of the Anion Inhibitor through Speciation and Micellar Formation

Abstract

Chemical inhibitors are widely used to protect metallic alloys from corrosion in aqueous environments. This Letter investigates the possible synergistic behavior of a quaternary ammonium carboxylate compound toward the development of a new system taking advantage of the surface activity of a known antimicrobial surfactant molecule, hexadecyl trimethylammonium cation, combined with a known organic corrosion inhibitor, the trans-4-hydroxy-cinnamate anion. Short-term potentiodynamic polarization (PP) studies combined with immersion in aqueous chloride solutions demonstrated the high inhibition efficiency of the combination of ions, and NMR pfg-diffusion measurements revealed micellar formation that was concentration- and pH-dependent. The NMR data suggest that speciation changes occur in the solution that correlate with enhanced corrosion inhibition efficiency at higher pH and at concentrations above the CMC of the compound. This new contribution may provide a rational molecular design toward delivering corrosion inhibitors to a metal surface through controlled speciation in solution.

Evaluation of a novel, multi-functional inhibitor compound for prevention of biofilm formation on carbon steel in marine environments

“…Increased environmental awareness and regulation stringency has forced marine industrial processes, particularly oil and gas operations, to switch to greener biocide alternatives. In a recent study by Ghorbani et al 25 , the authors described the novel OCI designated CTA-4OHcinn (Fig. 1 ) a compound expected to act both as a biocide and corrosion inhibitor simultaneously.…”

“…1 ) a compound expected to act both as a biocide and corrosion inhibitor simultaneously. The compound demonstrated corrosion inhibition efficiencies on CS (AISI 1030) when applied at 5, 7.5 and 10 mM of 95%, 95%, and 96% after 30 min 25 . The effective inhibition capacity is predicted to be the result of trans -4-hydroxy cinnamate or cetrimonium ions, or both, interacting with the surface and suppressing anodic cell development 25 .…”

“…High Resolution Mass Spectra (HRMS) were obtained on an Agilent 1200 series HPLC system, and the sample of CTA-4OHcinn was sent to The Campbell Microanalytical Laboratory, New Zealand for elemental analysis. The results of this analysis can be viewed elsewhere 25 .…”

“…For the present study, a novel multi-functional OCI was synthesised as described elsewhere 25 . The compound CTA-4OHcinn, is a quaternary ammonium carboxylate, which combines the organic trans -4-hydroxy-cinnamate anion with hexadecyl trimethyl ammonium cation.…”

“…The compound CTA-4OHcinn, is a quaternary ammonium carboxylate, which combines the organic trans -4-hydroxy-cinnamate anion with hexadecyl trimethyl ammonium cation. An established corrosion inhibition capacity exists for the organic anion through the formation of wormlike micelles, which attach to the CS substrate, forming a bilayer at the interface 25 . Additionally, the cation is a known antimicrobial surfactant 21 .…”