Synthesis and corrosion inhibition study of some 1,6-hexanediamine-based N,N-diallyl quaternary ammonium salts and their polymers

A variety of unsaturated N,N-diallyl compounds, capable of undergoing cyclopolymerization, are prepared from 1,6-hexanediamine. Selective monoformylation followed by allylation of the diamine afforded N,N-diallyl-N′-formyl-1,6-hexanediamine (DFH). The DFH was converted into quaternary ammonium monomers N,N-diallyl-N-carboethoxymethyl-N′-formyl-1,6-hexanediamine (DCFH) and N,N-diallyl-N-benzyl-N′-formyl-1,6-hexanediamine (DBFH)by reacting with ethyl chloroacetate and benzyl chloride, respectively. The monomer DCFH on homo- and co-polymerization (with SO2) afforded the polyelectrolytes poly(DFCH) and poly(DFCH-SO2), which on acidic hydrolysis of the amide and ester groups gave the corresponding polyampholytes. The monomer DBFH, likewise, on polymerization followed by acidic hydrolysis gave the corresponding polyelctrolytes. e synthesized materials (precursor to the monomers, monomers and the polymers containing quaternary, amide and trivalent nitrogens) and the starting 1,6-hexanediamine were used to study the corrosion inhibition of mild steel in 1 M HCl at 60°C for 6 h. The percent inhibition was found to be in the range 40–93%. There is a dramatic increase in the percent inhibition by the synthesized materials in comparison to the starting diamine.