| SM ISO690:2012|
GORINCHOY, Viorina; TURTA, Constantin; SHOVA, Sergiu; PARSHUTIN, Vladimir; SHOLTOYAN, Nicolai; KOVALI, Alexandr; CHERNYSHEVA, Natalia. Inhibition of steel corrosion in water heteronuclear salicylate complex. In: The International Conference dedicated to the 55th anniversary from the foundation of the Institute of Chemistry of the Academy of Sciences of Moldova. 28-30 mai 2014, Chișinău. Chișinău, Republica Moldova: Institutul de Chimie al AȘM, 2014, p. 106.
|The International Conference dedicated to the 55th anniversary from the foundation of the Institute of Chemistry of the Academy of Sciences of Moldova 2014|
Conferința "The International Conference dedicated to the 55th anniversary from the foundation of the Institute of Chemistry of the Academy of Sciences of Moldova" |
Chișinău, Moldova, 28-30 mai 2014
Natural and industrial water containing activating chloride and sulfate ions is quite aggressive environment in which steel corrosion of high speed occurs. Various organic substances including salicylic acid and its derivatives can be used as corrosion inhibitors. Salicylic acid is known to be used as a component of the disinfecting compositions, and acetylsalicylic acid- antifreeze coolant compositions. Phthalate or sodium salicylate are used for inhibiting corrosion of steel in distilled or tap water. However, they act as inhibitors at a temperature not exceeding 60ºC. Moreover, the protective properties of the aromatic acids salts are reduced in the presence of Cl-, SO4 2- and NO3 - ions, since these ions have harmful effect on the protective films formed on the steel in the presence of inhibitors. In some cases, sodium salicylate can be sufficiently effective moderator of steels corrosion in water, although it slightly worse than widespread sodium benzoate, which provides protection in a wide range of temperatures and pH values. But the disadvantage of sodium salicylate is the necessity of its high concentration, that can achieve more than 120 g/l in case of protection in tap water. In this comunication we present a heteronuclear salicylate complex [FeSr2(SalH)2(Sal)2(NO3)(DМАА)4] (Fig.1), where SalH-= C6H4OHCOO- (mono deprotonated), Sal2-= C6H4(O-)COO- (bi deprotonated), DMAA= dimethylacetamide (C4H9NO), at a concentration of 0.05-0.75 g/l, that was used as a corrosion inhibitor for closed steel pipe with the water supply. Fig.1 The molecular structure of [FeSr2(SalH)2(Sal)2(NO3)(DМАА)4] Corrosion losses of steel were reduced by more than 11 times (depending on the concentration of inhibitor and time trials), due to the following factors: adsorption of the inhibitor on the surface of the corroding steel; reducing the rate of the metal ionisation; interaction of the substance and its degradation products with Fe3+ ions and participation of formed complexes in creating of corrosion protective coating layers. It is important to mention, that the degree of its action little changed at different times of the test.