Inhibitor protection of steel corrosion in acid solutions at high temperatures. A review. Part 2

• Ya.G. Avdeev and Yu.I. Kuznetsov

A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31, 119071 Moscow, Russian Federation

Abstract: Data from scientific and patent literature concerning the protection of steels in acid solutions by unsaturated organic compounds (UCs) and formulations based on them at temperatures (t) up to 250°C are generalized. It is noted that individual acetylenic compounds, unsaturated aldehydes, ketones and azomethines are rarely efficient in steel protection in HCl solutions at t>100°C. However, composite inhibitors based on some of these compounds allow their protective range to be expanded up to t=250°C in certain cases. Data on the protection of various steels by such composite inhibitors is discussed. It is noted that high-temperature HCl solutions are the most acceptable corrosive environments for the application of such inhibitors. Issues related to the mechanism of the inhibitory effect of UCs are discussed. It is shown that the possibility of protecting steel at these high temperatures is a consequence of the unique inhibition mechanism of UCs that results from their ability to be chemisorbed on a metal surface and undergo deep chemical transformations to form protective polymer films. The drawbacks that limit the use of composite corrosion inhibitors containing UCs include their instability in hot corrosive media in the course of time, i.e., polymerization in the acid bulk that removes the inhibitor from the corrosive environment, which leads to its coking. Moreover, the UCs themselves and the additives used in combination with them are extremely toxic compounds. The bibliography includes 138 sources.

Keywords: high-temperature acid corrosion, steel, corrosion inhibitors, acidizing, hydrochloric acid, unsaturated organic compounds, acetylenic compounds, propargyl alcohol, unsaturated aldehydes, cinnamaldehyde, unsaturated ketones, azomethines

Int. J. Corros. Scale Inhib., 2020, 9, no. 3, 867-902 PDF (604 K)
doi: 10.17675/2305-6894-2020-9-3-5

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