Study of 1-(4-Isohexylphenoxy)-3-propylpyridinium and 1-(4-Isohexylphenoxy-2-diethylaminomethyl)-3-propylpyridinium Bromide As Inhibitors of Acid Corrosion

Results are presented from gravimetric anti-corrosion studies of pyridine salts 1-(4-isohexylphenoxy-)-3-propylpyridinium bromide (I) and 1-(4-isohexylphenoxy-2-diethylaminostil-)-3-pyridinium bromide (II) on St. 3 steel in 0.5 N Н₂SO₄. The effect the temperature (298, 303, 313, 323, 333 K) and concentrations of compounds (0.025, 0.05, and 0.1 g/L) have on the rate of corrosion and protective effect is studied (duration of test, 3 h). It is established that compounds I and (especially) II are strong inhibitors: the degree of protection against corrosion for St.3 steel at concentrations of 0.1 g/L is 96% on average. The thermodynamic parameters of the process (ΔG, ΔH, and ΔS) are calculated, and the blocking mechanism for protecting the metal surface from corrosion is considered.