Schiff bases as corrosion inhibitors for copper in hydrochloric acid / Nurhadilah Che Harun

Five Schiff bases, N,N’-bis(salicylaldehyde)-l,2-ethylenediamine (salen N,N’-bis(3methoxysalicylidene)-l,2-ethylenediamine (MeO-salen), N,N'-bis (5- nitrosalicylidene)-l,2-ethylenediamine (N02-salen),N,N'-bis(2-hydroxy acetophenone) (hapen) and N,N’-bis(2-hydroxy-5-nitroacetophenone) (NO2- hapen) have been successfully synthesized by reaction of ethylenediamine with the appropriate aldehye or ketone in the ratio 1:2. The Schiff base ligands are characterized by using elemental analysis, infrared spectroscopy, JH NMR spectroscopy and melting point determination. The compounds are examined for their inhibitive effect toward corrosion of copper metal in 1M hydrochloric acid by using the weight loss method. The effect of different concentrations of each compound, ranging from 0.01M to 0.0001M toward inhibiting corrosion is investigated. The results show the most effective Schiff base as an inhibitor of corrosion is MeO-salen at the concentration 0.01M with inhibiting efficiency of 64.90%.