Amide type nonionic surfactants: Synthesis and corrosion inhibition evaluation against carbon steel corrosion in acidic medium

Three nonionic cleavable surfactants were prepared from the reaction of sebacic acid and antipyrine and polyethylene glycols with different molecular weights. The chemical structures of the prepared surfactants were determined using FTIR and 1H NMR spectroscopy. The surface activities of the prepared surfactants were measured based on the surface tension measurements at different temperatures. The surface parameters including: surface tension, critical micelle concentration (CMC), maximum surface excess (max) and minimum surface area. The prepared surfactants were evaluated as corrosion inhibitors to prevent the dissolution of carbon steel in 1 M HCl using gravimetric method. The results showed that the inhibition efficiency of these compounds is increased by increasing their concentration, immersion time and polyethylene glycol chain length. Where the inhibitive efficiencies of the prepared surfactants at higher immersion time (120 h), increased considerably to the maximum values in the range of 93.8%-98.5% at 800 ppm by weight and in the range of 77.8-87.6% at 25 ppm by weight. The study showed the strong relation between the surface activities of the nonionic surfactants and their inhibition efficiency in the carbon steel protection in 1 M HCl.