Novel trimeric cationic pyrdinium surfactants as bi-functional corrosion inhibitors and antiscalants for API 5L X70 carbon steel against oilfield formation water

Three trimeric cationic pyridinium surfactants (APMC6, APMC12 and APMC18), were synthesized via esterification reaction, followed by a quaternization reaction, and characterized by micro-elemental analysis, FTIR, and 1HNMR spectroscopy. Surface-active parameters for APMC compounds were investigated using surface tension measurements. The critical micelle concentration values declined as a function of the alkyl chain length. The corrosion inhibition performance of these surfactants was studied on API 5L X70 carbon steel against oilfield formation water as corrosive medium by various electrochemical techniques. The results indicated that APMC surfactants showed superior corrosion inhibitive activity, as the inhibition efficiency (%I.E.) was up to 94% for APMC18. Atomic force microscopy confirmed the creation of a protective layer on the carbon steel surface. Furthermore, the anti-scaling aspects of APMC compounds were investigated using static scale precipitation technique. The data revealed that the scale inhibition performance elevated by increasing the dosage of APMC compounds. Both anti-corrosion and anti-scaling results supported the potential multifunctional use of APMC compounds against corrosion and scale problems in formation water. Finally, quantum chemical calculations and Monte Carlo simulations were computed to fulfill a rationale of the obtained experimental data.