Corrosion inhibition of mild steel by some pyrazole derivatives in aqueous HCl solutions

Chemistry Department, Faculty of Science, Cairo University, Giza, A. R. Egypt Manuscript received 14 March 2000, revised 13 June 2000, accepted 7 July 2000 The inhibitive properties of pyrazole derivatives (1-9) for corrosion of mild steel in 0.5 M HCI solution have been evaluated. For some derivatives the efficiency value is 97%. Langmuir absorption isotherm and Hammett substitution constants for these derivatives are in agreement with the galvanostatic measurements. Greater inhibition has been obtained with electron-withdrawing substiuents than with electron-donating ones