Synthesis of bolaamphiphile surfactants and their inhibitive effect on carbon steel corrosion in hydrochloric acid medium

Corrosion inhibition by surfactant molecules is related to the surfactant's ability to aggregate at interfaces and in solution. In this work some new triazole bolaamphiphiles in the series of l,n-bis(1,2,4-triazolyl)alkane where n = 10, 12 have been synthesized. The purity of surfactants synthesized was checked by rutinary methodologies (IR, H-1 NMR, C-13 NMR, mass spectra and elemental analysis). The aggregation of l,n-bis(l,2,4-triazolyl)alkane have been determined by surface tension at the air-HCl 1 M interface. The inhibiting action of these compounds towards the corrosion of carbon steel in 1 M HCl solution was investigated using gravimetric, potentiodynamic and electrochemical impedance spectroscopy measurements. Polarization data indicate that these compounds act as very good cathodic inhibitors for carbon steel in 1 M HCl. The values of the transfer resistance, obtained from impedance plots of carbon steel, increase by increasing product concentration. From all measurements carried out, the variation of the inhibition efficiency versus concentration shows the same trend. The electrochemical study shows that DTC12 is the best inhibitor and its efficiency increases with concentration and the highest value obtained is around 94%. (C) 2004 Elsevier Ltd. All rights reserved.