Abstract
This study examines the use of new imidazolium-based ionic liquids derivatives, namely 3-(3-phenylpropyl)-1-propyl-1H-imidazol-3-ium bromide (PPIB1) and 3-(4-phenoxybutyl)-1-propyl-1H-imidazol-3-ium bromide (PPIB4) for corrosion and dissolution protection of C38 steel in normal hydrochloric acid solution. The inhibiting efficiency of the different additives was evaluated by means of weight loss and electrochemical techniques such as AC impedance measurements and polarization curves. The experimental results obtained reveal that PPIB4 was the most effective inhibitor. The variation in inhibitive efficiency mainly depends on the type and nature of the substituents present in the inhibitor molecule. Polarization curves showed that the new imidazolium ionic liquids were mixed-type inhibitors in 1 M HCl. The inhibition efficiency increased with imidazolium ionic liquids concentration and attained the maximum value of 94.2% in the case of PPIB4 at 10(-2) M. The results obtained from weight loss and electrochemical studies were in reasonable agreement. The adsorption of PPIB1 and PPIB4 on the steel surface obeyed to the Langmuir isotherm model. The thermodynamic data of activation were determined and discussed.