Study On Corrosion Inhibition Performance And The Adsorption On Metal Surface Of Novel Nitrogen Containing Organic Molecules

The corrosion caused huge economic losses and great harm every year,adding corrosion inhibitor is an economical and efficient way in a large number of anti-corrosion measurements,a small amount of corrosion inhibitor can greatly reduce the corrosion of metal.This paper studied three kinds of nitrogen containing inhibitors:two methyl of benzene piperidine derivatives C₁₈H₂₈N₂-2(C_nH_2n+1)·2Cl,benzene two methyl group of fourteen alkyl two alkyl quaternary ammonium salts C₈H₈·2[N·C₁₄H₂₉·2(C_n H_2n+1)]·2Cl and hexamethylenetetramine quaternary ammonium salts C₆H₁₂N₄-C_nH_2n+1·Br.We use weight loss measurement,polarization measurement to study the inhibition behavior on carbon steel in hydrochloric acid solution,the thermodynamic and kinetic parameters have been analyzed,quantum chemistry calculations are also carried out.The mechanism of corrosion inhibition was investigated,the main results are as follows:（1）The adsorption behavior of two methyl of benzene piperidine derivatives follow the Langmuir isotherm model on the surface of carbon steel,the adsorption process is chemical adsorption,the adsorption process is an exothermic process,rising temperature is not conducive to the adsorption process.After adding the inhibitors,the activation energy of the reaction is increased,and the barrier of the corrosion reaction is increased,thus increasing the difficulty of corrosion reaction.（2）The adsorption behavior of benzene two methyl group of fourteen alkyl two alkyl quaternary ammonium salts follow the Langmuir isotherm model on the surface of carbon steel,the adsorption process is physical adsorption,and the adsorption process is exothermic,rising temperature is not conducive to the adsorption process.After adding the inhibitor,the activation energy of the reaction is increased,and the barrier of the corrosion reaction is increased.At the same time,it is shown that the this kind of corrosion inhibitor is cathodic corrosion inhibitor but raising the temperature it tends to inhibit the anodic corrosion by the electrochemical study.（3）The adsorption behavior of hexamethylenetetramine quaternary ammonium salt derivatives follow the Langmuir isotherm model on the surface of carbon steel,the adsorption process has both physical and chemical adsorption,the adsorption process is an endothermic process,rising temperature is beneficial to the adsorption process.Electrochemical studies show that this kind of corrosion inhibitor is cathodic corrosion inhibitor but raising the temperature it tends to inhibit the anodic corrosion,the quantum chemistry calculation of hexamethylenetetramine quaternary ammonium salt derivatives show that increasing the length of carbon chain is conducive to improve the efficiency of corrosion inhibition,which is consistent with the results of weight loss method.