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Influence of different anions on the corrosion-inhibition performance of pyridyl ionic liquids

Lei Fan, Yuan Gao, Qiang Bi, Long Shi, Changbin Tang, Chengxian Yin, and Juanqin Xue

State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, Xi’an, China



Received: 28 July 2023  Accepted: 1 October 2023


In this study, it was possible to investigate the effect of pyridine-type ionic liquids with the bromides Br, BF4 and PF6 in N-butyl-4-methylpyridine (B4MePyBr), N-butyl-4-methylpyridinium tetrafluoroborate (B4MePyBF4) and N-butyl-4-methylpyridinium hexafluorophosphate (B4MePyPF6) as the anions on the reduction of corrosion on N80 steel in hydrochloric acid solution. A loss-in-weight test showed that the corrosion-inhibition efficiency increased with an increase of the corrosion inhibitor concentration, and the corrosion-inhibition efficiency reached 87.1% when B4MePyBF4 was added at a concentration of 10.0 mmol·L−1 at 25 °C. The corrosion-inhibition efficiency of the three followed B4MePyBF4 > B4MePyBr > B4MePyPF6. Surface morphology tests showed that the corrosion inhibitors were effectively adsorbed on the carbon steel surface and the adsorbed film layer was tight. Quantum calculations showed that the LUMO and HOMO orbital energy polarities of B4MePyBF4 were the smallest, indicating that it most strongly adsorbed on the metal surface and had the best retardation effect, which was consistent with the actual experimental results.

Graphical abstract

The corrosion-inhibition behavior of B4MePyBF4, B4MePyBr, and B4MePyPF6 in hydrochloric acid on N80 steel was investigated. The corrosion-inhibition efficiency increased with corrosion inhibitor concentration. The corrosion-inhibition efficiency of the three followed the trend B4MePyBF4 > B4MePyBr > B4MePyPF6.

Keywords: Ionic liquids; Corrosion inhibitors; Hydrochloric acid; N80 steel; Orbital energy polarities

Full paper is available at

DOI: 10.1007/s11696-023-03131-5


Chemical Papers 78 (2) 927–936 (2024)

Tuesday, May 21, 2024

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