Diallyl‐1,12‐diaminododecane‐based cyclopolymers and their use as inhibitors for mild steel corrosion

A variety of N,N ‐diallyl compounds, capable of undergoing cyclopolymerization, are prepared from 1,12‐dodecanediamine. Selective monoformylation followed by allylation of the parent diamine afforded N,N ‐diallyl‐ N′ ‐formyl‐1,12‐dodecanediamine which was converted into quaternary ammonium monomers N,N ‐diallyl‐ N ‐benzyl (or p ‐methoxybenzyl)‐ N ′‐formyl‐1,12‐dodecanediamine by reacting with benzyl‐ or p ‐methoxybenzyl chloride. The monomers on homo‐ and co‐cyclopolymerization (with SO 2 ) afforded the cationic polyelectrolytes which on acidic hydrolysis of the formyl group gave water‐soluble polyelctrolytes. All the synthesized monomers, polymers, and the starting 1,12‐dodecanediamine were used to study the corrosion inhibition of mild steel by gravimetry and electrochemical methods in acidic and saline media at 60°C. The inhibitor molecules (at a concentration of 400 ppm) exhibited inhibition efficiencies (%IE) in the ranges 62%–99% in 1 M HCl, 95%–99% in 4 M HCl, 13%–91% in 7.7 M HCl, 13%–91% in 0.5 M H 2 SO 4 , and 75%–90% in 3.5% NaCl. There is a dramatic increase in the IEs by the monomers and polymers in comparison to the parent diamine. POLYM. ENG. SCI., 2012.