Synthesis and Study of 1-Alkenyl-2-propargyloxy-3-aminomethylbenzenes as Acid Corrosion Inhibitors and Antimicrobial Additives to Cutting Fluids

Abstract

A series of polyfunctional organic compounds, 1-propenyl- and 1-allyl-2-propargyloxy-3-aminomethylbenzenes containing simultaneously an aminomethyl group and fragments with С=С and С≡С bonds, were prepared in high yield (77.6–94%) by Mannich ternary condensation of 2-propenyl- and 2-allylphenols and their p-methyl-substituted derivatives with formaldehyde and secondary amines (diethylamine, piperidine, and morpholine), followed by the reaction of the products with propargyl bromide. The structures of the compounds were confirmed by the NMR spectra. The compounds were studied as inhibitors of acid corrosion of St3 steel and as antimicrobial additives to cutting fluids. 1-Propenyl-2-propargyloxy-3-diethylaminomethylbenzene showed the highest protective performance. At its concentration of 0.01 and 0.05 g L^–1, the degree of corrosion protection of St3 steel in 0.5 М Н₂SO₄ was 92.0 and 99.6% (at 25°C) and 70.0 and 98.7% (at 60°C), respectively. 1-Propenyl- and 1-allyl-2-propargyloxy-3-aminomethylbenzenes (in 0.25–1% concentrations) showed only bactericidal properties, whereas the p-methyl-substituted derivative, 1-methyl-3-allyl-4-propargyloxy-5-morpholinomethylbenzene, showed high bactericidal and fungicidal properties simultaneously. 1-Propenyl- and 1-allyl-2-propargyloxy-3-aminomethylbenzenes surpass the known antimicrobial additive, 8-hydroxyquinoline, in the bactericidal performance at identical concentrations, and 1-methyl-3-allyl-4-propargyloxy-5-morpholinomethylbenzene surpasses it in both bactericidal and fungicidal performance.