Synthesis of Quaternary Salts Based on 2-Allyl-4-isohexyl-6-aminomethylphenols and Study of Their Anticorrosive Properties in 0.5N H2SO4

The paper is devoted to the synthesis of quaternary bromine-containing ammonium salts based on 2-allyl-4-isohexyl-6-diethylaminomethylphenol and 2-allyl-4-isohexyl-6-piperidinomethylphenol and their study as inhibitors of acid corrosion of steel St.3 (in 0.5N H2SO4). The inhibitory properties were studied on plates of unalloyed steel St.3 using the gravimetric method (time 3 h). The influence of temperature (298, 313, and 333 K) and concentration (0.025, 0.05, and 0.1 g/L) on the main indicators of the corrosion process of steel St.3 (corrosion rate, filling area, and protective effect) was investigated. The degree of protection (Z) was 90.3 and 98.8%, respectively (at a concentration of 0.1 g/L). Based on the laboratory data, the main thermodynamic parameters of the adsorption process (ΔG, ΔH, ΔS) were calculated. The behavior of bromine-containing ammonium salt compounds as acid corrosion inhibitors can obviously be explained by their high chemisorption on the metal surface (blocking mechanism of corrosion suppression).