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 cyclo polymerization, are prepared from 1,6-hexanediamine. Selective monoformylat ion followed by allylation of the diamine afforded N,N-Niallyl-N'-formyl-1, 6-hexanediamine (DFH). The DFH was converted into quaternary ammonium monom ers 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 eth yl chloroacetate and benzyl chloride, respectively. The monomer DCFH on hom o- and co-polymerization (with SO2) afforded the polyelectrolytes poly(DFCH ) and poly(DFCH-SO2), which on acidic hydrolysis of the amide and ester gro ups gave the corresponding polyampholytes. The monomer DBFH, likewise, on p olymerization followed by acidic hydrolysis gave the corresponding polyelec trolytes. All the synthesized materials (precursor to the monomers, monomers and the polymers containing quaternary, amide and trivalent nitrogens) and the star ting 1,6-hexanediamine were used to study the corrosion inhibition of mild steel in 1 M HCl at 60 degreesC for 6 h. The percent inhibition was found t o be in the range 40-93%. There is a dramatic increase in the percent inhib ition by the synthesized materials in comparison to the starting diamine. ( C) 2001 Elsevier Science Ltd. All rights reserved.