Synthesis and characterization of Trimethoprim metal complexes used as corrosion inhibitors for carbon steel in acid media

Abstract

Trimethoprim (TM) is an antibiotic used to treat bacterial infections as well as it is a heterocyclic compound, whose structure consists of 1,2,3-trimethoxybenzene and pyrimidine-2,4-diamine, therefore it can be used as a corrosion inhibitor due to easy production and low price on carbon steel in acidic media by adsorption process. Cr(III), Mn(II), Co(II), Ni(II) and Cu(II) complexes of Trimethoprim were synthesized and also used as a corrosion inhibitor. The Trimethoprim drug and its complexes were characterized by different spectroscopic methods: Ultraviolet-visible, Fourier transform infrared, conductivity measurements, thermal analysis (TG) and magnetic susceptibility measurement. Adsorption process can be attributed to changes in concentration of inhibitors with the acidity of a solution as well as the surface of the metal (carbon steel). The results of the experiment have shown the coordination of the Trimethoprim drug with the transition metal ions through nitrogen of pyrimidinyl ring so that square planar geometry was suggested for Mn(II), Ni(II), Cu(II) complexes while the Cr(III), Co(II) complexes have an octahedral geometry and these complexes have electrolyte properties. Corrosion inhibition on carbon steel was studied using weight loss method in one molar hydrochloric acid solution by organic inhibitor Trimethoprim and inorganic inhibitors (complexes) at different concentrations with different periods of time. The measurements have shown that Trimethoprim reduced the corrosion of the carbon steel surface and also the inhibition efficiency of the complexes increased with increasing concentration. The inhibition efficiency followed the order Co > Cu > Cr in one molar acidic solution.

Exploration of rice husk ash as a green corrosion inhibitor immersed in NH4Cl 7.5 % solution

“…Moreover, the increased value of i corr (0.849–7.027 μA/cm 2 ) by increasing in temperature corresponds to the lower thermal stability of inhibitors at higher temperatures and the loss of inhibitor efficacy (see Fig. 1 b) [ 18 ] despite the inhibitor remaining capable to quarantine the metal from the corrodent under NH 4 Cl environment.…”

Corrosion Evaluation and Inhibiting Effect of Chlorpheniramine Drug on Mild Steel in HCl Acid

“…Several ways are used for fighting and protecting corrosion of mild steel, among which inhibitor compounds have been found to be excellent protection by retarding the corrosion reaction during use [1,2]. Corrosion inhibitors [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] are usually used to control corrosion effect by forming film barrier adorption, by altering the cathodic reaction and by protecting the anodic reaction, in order to mitigate the flow of corrosion on the metal material. However, inhibitors in some cases are harmful to the environment [18][19][20] and this empowered excellent search for non harmful inhibitors such as drugs on metal materials in acidic environments [21][22][23].…”

Electrochemical Quantification of Corrosion Mitigation on Iron Surfaces with Gallium(III) and Zinc(II) Metallosurfactants

“…Relevant to this study, the pretreatment layer is directly physisorbed or chemisorbed to the metal surface and chromium­(III)-based systems have been traditionally favored. , Environmental concerns with hexavalent chromium impose steep restrictions to the use of chromium-based coatings . The discovery of new and more benign inhibitors has attracted considerable attention, − and surfactants figure among well-known molecular inhibitors. ,− …”