Effect of some 2-Arylhydrazonobenzothiazoles on the Kinetics of Corrosion of Al-Mn Alloy in Acidic Medium

Manuscript received 22 September 1989, revised 15 November 1990, accepted 24 April 1991

The effect of 2-(o-OH, p-OH, p-OCH₃ and p-N(CH₃)₂ benzaldehyde) hydrazo­nobenzothiazoles on the kinetics of corrosin of Al—Mn alloy in 2.5 mol dm^-3 hydro­chloric acid has been investigated using a new approach of Mylius thermometric method. It is found that at low concentrations, the o-OH and p-OH compounds have the highest inhibition effect. Within the concentration range (5-10) x 10^-4 mol dm^-3, the order is p-OCH₃>o-OH >p.OH>p-N(CH₃)₂. A correlation with electronic structure, substituent and its position, concentration, nature and stability of the formed complexes and the inhibition order of the compounds has been discussed.