The objective of this paper is to evaluate the corrosion resistance of API X70 steel in three different protic ionic liquids (PILs). Protic ionic liquids cation was 2-hydroxiethylammonium, and their anion was a carboxylate where the carbon chain length was varied. The synthetised PILs were characterised by nuclear magnetic resonance. The corrosion resistance of API X70 steel was evaluated on the hand of the monitoring of the open circuit potential and electrochemical impedance spectroscopy. Results showed that PIL adsorption on the substrate surface occurs to form a film that enhances corrosion inhibition effects. However, the adsorbed film can break due to desorption that exposes the substrate surface and promotes corrosion of the substrate. In addition, it was observed that corrosion inhibition effects improve with the increase in the anion carbon chain length, since the longer is the anion the larger is the substrate coverage.
AlvarezV. H.MattediS.Martin-PastorM.AznarM. and IglesiasM.: ‘Thermophysical properties of binary mixtures of {ionic liquid 2-hydroxy ethylammonium acetate+(water, methanol, or ethanol)}’J. Chem. Thermodyn., 201143997–1010. doi: 10.1016/j.jct.2011.01.014
2.
AlvarezV. H.MattediS. and AznarM.: ‘Isobaric (vapor+liquid) equilibria of 1-ethyl-3-methylimidazolium ethylsulfate plus (propionaldehyde or valeraldehyde): Experimental data and prediction’J. Chem. Thermodyn., 201143895–900. doi: 10.1016/j.jct.2011.01.008
3.
MattediS.CarvalhoP. J.CoutinhoJ. A. P.AlvarezV. H. and IglesiasM.: ‘High pressure CO2 solubility in N-methyl-2-hydroxyethylammonium protic ionic liquids’J. Supercrit. Fluids201156224–230. doi: 10.1016/j.supflu.2010.10.043
4.
AlvarezV. H.DosilN.Gonzalez-CabaleiroR.MattediS.Martin-PastorM.IglesiasM. and NavazaJ. M.: ‘Brønsted ionic liquids for sustainable processes: synthesis and physical properties’J. Chem. Eng. Data201055625–632. doi: 10.1021/je900550v
5.
IglesiasM.TorresA.Gonzalez-OlmosR. and SalvatierraD.: ‘Effect of temperature on mixing thermodynamics of a new ionic liquid: {2-Hydroxy ethylammonium formate (2-HEAF)+short hydroxylic solvents}’J. Chem. Thermodyn., 200840119–133. doi: 10.1016/j.jct.2007.05.011
6.
PericB.MartíE.SierraJ.CruañasR.IglesiasM. and GarauM. A.: ‘Terrestrial ecotoxicity of short aliphatic protic ionic liquids’Environ. Toxicol. Chem., 2011302802–2809. doi: 10.1002/etc.683
7.
BelieresJ. -P. and AngellC. A.: ‘Protic ionic liquids: preparation, characterization, and proton free energy level representation’J. Phys. Chem., B2007111B4926–4937. doi: 10.1021/jp067589u
8.
AbbottA. P.FrischG. and RyderK. S.: ‘Electroplating using ionic liquids’Annu. Rev. Mater. Res., 201343335–358. doi: 10.1146/annurev-matsci-071312-121640
9.
AnoutiM.JacqueminJ. and PorionP.: ‘Transport properties investigation of aqueous protic ionic liquid solutions through conductivity, viscosity, and NMR self-diffusion measurements,’J. Phys. Chem., B2012116B4228–4238. doi: 10.1021/jp3010844
10.
AnoutiM.Caillon-CaravanierM.DridiY.GalianoH. and LemordantD.: ‘Synthesis and characterization of new pyrrolidinium based protic ionic liquids. good and superionic liquids’J. Phys. Chem., B2008112B13335–13343. doi: 10.1021/jp805992b
11.
ÁlvarezV. H.MattediS.Martin-PastorM.AznarM. and IglesiasM.: ‘Synthesis and thermophysical properties of two new protic long-chain ionic liquids with the oleate anion’Fluid Phase Equilibria201029942–50. doi: 10.1016/j.fluid.2010.08.022
12.
SantosR. F.FalcadeT.KunstS. R.Ortega-VegaM. R.MattediS.IglesiasM. and MalfattiC. F.: ‘Electrochemical study of AISI 1004 steel in protic ionic liquids: influence of carbon chain CD’. Proc. Conf. on ‘Eurocorr2013’, Estoril, Portugal, September 2013, European Federation of Corrosion, Paper 1496.
13.
Ortega VegaM. R.KunstS. R.MattediS.IglesiasM. and MalfattiC. F.: ‘Corrosion study of API X70 in three different protic ionic liquids’. Proc. Conf. on ‘Intercorr2014’, Fortaleza, CE, Brazil, May 2014, Associação Brasileira de Corrosão, Paper 118.
14.
GaoG. and LiangC. H.: ‘1,3-Bis-diethylamino-propan-2-ol as volatile corrosion inhibitor for brass’Corros. Sci., 2007493479–3493. doi: 10.1016/j.corsci.2007.03.030
15.
FinšgarM. and MerlD. K.: ‘2-Mercaptobenzoxazole as a copper corrosion inhibitor in chloride solution: electrochemistry, 3D-profilometry, and XPS surface analysis’Corros. Sci., 20148082–95. doi: 10.1016/j.corsci.2013.11.022
16.
FinšgarM.: ‘2-Mercaptobenzimidazole as a copper corrosion inhibitor: Part I. Long-term immersion, 3D-profilometry, and electrochemistry’Corros. Sci., 20137282–89. doi: 10.1016/j.corsci.2013.03.011
17.
FinšgarM. and MiloševI.: ‘Inhibition of copper corrosion by 1,2,3-benzotriazole: a review’Corros. Sci., 2010522737–2749. doi: 10.1016/j.corsci.2010.05.002
18.
RammeltU.KoehlerS. and ReinhardG.: ‘Synergistic effect of benzoate and benzotriazole on passivation of mild steel’Corros. Sci., 2008501659–1663. doi: 10.1016/j.corsci.2008.02.016
19.
HegazyM. A.AbdallahM.AwadM. K. and RezkM.: ‘Three novel di-quaternary ammonium salts as corrosion inhibitors for API X65 steel pipeline in acidic solution. Part I: experimental results’Corros. Sci., 20148154–64. doi: 10.1016/j.corsci.2013.12.010
20.
ZhangJ.GongX. -L.SongW. -W.JiangB. and DuM.: ‘Synthesis of imidazoline-based dissymmetric bis-quaternary ammonium gemini surfactant and its inhibition mechanism on 35 steel in hydrochloric acid medium’Mater. Corros., 201263636–645.
21.
RammeltU.KoehlerS. and ReinhardG.: ‘Use of vapour phase corrosion inhibitors in packages for protecting mild steel against corrosion’Corros. Sci., 200951921–925. doi: 10.1016/j.corsci.2009.01.015
22.
MorettiG.GuidiF. and GrionG.: ‘Tryptamine as a green iron corrosion inhibitor in 0·5 M deaerated sulphuric acid’Corros. Sci., 200446387–403. doi: 10.1016/S0010-938X(03)00150-1
23.
BakerH. R.ShafrinE. G. and ZismanW. A.: ‘The adsorption of hydrophobic monolayers of carboxylic acids’J. Phys. Chem., 195256405–412. doi: 10.1021/j150495a024
24.
BastidasD. M.CanoE. and MoraE. M.: ‘Volatile corrosion inhibitors: a review’Anti-Corros. Methods Mater., 20055271–77. doi: 10.1108/00035590510584771
25.
BoisierG.LamureA.PébèreN.PortailN. and VillatteM.: ‘Corrosion protection of AA2024 sealed anodic layers using the hydrophobic properties of carboxylic acids’Surf. Coat. Technol., 20092033420–3426. doi: 10.1016/j.surfcoat.2009.05.008
26.
ShawabkehR.RihanR. and AL-BakerN.: ‘Effect of an alkyl amine-based corrosion inhibitor for 1018 carbon steel pipeline in sea water’Anti-Corros. Methods Mater., 201360259–270. doi: 10.1108/ACMM-06-2013-1270
27.
GoudarziN. and FarahaniH.: ‘Investigation on 2-mercaptobenzothiazole behavior as corrosion inhibitor for 316-stainless steel in acidic media’Anti-Corros. Methods Mater., 20136120–26. doi: 10.1108/ACMM-11-2012-1223
28.
SkinnerW.: ‘A new method for quantitative evaluation of volatile corrosion inhibitors’Corros. Sci., 1993351491–1494. doi: 10.1016/0010-938X(93)90376-R
29.
ReinhardG.RadtkeM. and RammeltU.: ‘On the role of the salts of weak acids in the chemical passivation of iron and steel in aqueous solutions’Corros. Sci., 199233307–313. doi: 10.1016/0010-938X(92)90154-U
30.
FrignaniA.GrassiV.ZucchiF. and ZanottoF.: ‘Mono-carboxylate conversion coatings for AZ31 Mg alloy protection’Mater. Corros., 201162995–1002. doi: 10.1002/maco.200905615
31.
ZucchiF.GrassiV. and ZanottoF.: ‘Sodium monocarboxylates as inhibitors of AZ31 alloy corrosion in a synthetic cooling water’Mater. Corros., 200960199–205. doi: 10.1002/maco.200805045
32.
SolomonsT. W. G. and FryhleC. B.: ‘Organic chemistry’10th edn.385–458; 2011Hoboken, NJJohn Wiley & Sons, Inc.
RammeltU.KöhlerS. and ReinhardG.: ‘EIS characterization of the inhibition of mild steel corrosion with carboxylates in neutral aqueous solution’Electrochim. Acta2008536968–6972. doi: 10.1016/j.electacta.2008.01.004
35.
PapavinasamS.: ‘Corrosion inhibitors, Ch. 71’, in ‘Uhlig's corrosion handbook’3rd edn.1021–1032; 2011New York, NYJohn Wiley & Sons, Inc.
36.
TanY. J.BaileyS. and KinsellaB.: ‘An investigation of the formation and destruction of corrosion inhibitor films using electrochemical impedance spectroscopy (EIS)’Corros. Sci., 1996381545–1561. doi: 10.1016/0010-938X(96)00047-9
37.
PopovaA. and ChristovM.: ‘Evaluation of impedance measurements on mild steel corrosion in acid media in the presence of heterocyclic compounds’Corros. Sci., 2006483208–3221. doi: 10.1016/j.corsci.2005.11.001
38.
GabrielliC.: ‘Identification of electrochemical processes by frequency response analysis’1984;. Technical report number 004/83, Solartron Analytical, Farnborough, UK.
39.
FinšgarM.FassbenderS.NicoliniF. and MiloševI.: ‘Polyethyleneimine as a corrosion inhibitor for ASTM 420 stainless steel in near-neutral saline media’Corros. Sci., 200951525–533. doi: 10.1016/j.corsci.2008.12.006
40.
MartinezS. and Metikoš-HukovićM.: ‘A nonlinear kinetic model introduced for the corrosion inhibitive properties of some organic inhibitors’J. Appl. Electrochem., 2003331137–1142. doi: 10.1023/B:JACH.0000003851.82985.5e
41.
MaH.ChengX.LiG.ChenS.QuanZ.ZhaoS. and NiuL.: ‘The influence of hydrogen sulfide on corrosion of iron under different conditions’Corros. Sci., 2000421669–1683. doi: 10.1016/S0010-938X(00)00003-2
42.
McCaffertyE. and HackermanN.: ‘Double layer capacitance of iron and corrosion inhibition with polymethylene diamines’J. Electrochem. Soc., 1972119146–154. doi: 10.1149/1.2404150
43.
Babic-SamardžijaK.KhaledK. F. and HackermanN.: ‘Heterocyclic amines and derivatives as corrosion inhibitors for iron in perchloric acid’Anti-Corros. Methods Mater., 20055211–21. doi: 10.1108/00035590510574871
44.
ToshimaS. and UchidaI.: ‘Specific adsorption of halide ions at the germanium electrolyte-solution interface; frequency dispersion of interfacial impedance’Electrochim. Acta1970151717–1732. doi: 10.1016/0013-4686(70)80092-5
45.
Babić-SamardžijaK. and HackermanN.: ‘Triazole, benzotriazole and substituted benzotriazoles as corrosion inhibitors of iron in aerated acidic media’J. Solid State Electrochem., 20059483–497. doi: 10.1007/s10008-004-0584-z
46.
GojićM.: ‘The effect of propargylic alcohol on the corrosion inhibition of low alloy CrMo steel in sulphuric acid’Corros. Sci., 200143919–929. doi: 10.1016/S0010-938X(00)00128-1
47.
BarsoukovE. and MacdonaldJ. R.: ‘Impedance spectroscopy: theory, experiment and applications’2nd edn.Chap. 227–128; 2005Hoboken, NJJohn Wiley & Sons, Inc.
48.
MayneJ. E. O. and PageC. L.: ‘Inhibition of the corrosion of iron by benzoate and acetate ions’Br. Corros. J., 19749223–226. doi: 10.1179/000705974798321152
