Synthesis and Study of Different Thioamides as Corrosion Inhibitors

Abstract

Many organic compounds having electron rich atoms in their structures, such as nitrogen, and sulphur are widely use in lubricating additives, in the oil industry to minimize corrosion. The presence of electron rich atoms in the molecules increases its ability to form coordinate covalent bonds with the metal atoms, involved in the corrosion environment. Compounds based on fatty amines, aromatic amines, imidazoline, diamidazoline, and fatty amides are now, uses as corrosion inhibitors, in the oil sector and are available in the market. In this work, some phenyl acetothioamide and benzyl acetothioamide are synthesized. The chemical and physical data of the prepared compounds are compiled. The solubility, cold stability, heat stability, and corrosion inhibitors characteristics, of the compounds have been measured in the artificial environment (10% crude in artificial brine at pH 4.5–4.8). Prepared thioamides differs in their molecular weights, due to presence of different organic substituent's, on the thioamides group. Synthesis of the above mentioned compounds are based on the Willgerodt-Kindler reaction. The compounds are confirmed by IR, NMR, UV-VIS, and other wet chemical analytical techniques. The experimental values of the elemental composition were compared with the calculated values and found agreeing. UV-VIS. and IR spectra also show the absorption peaks, which confirm the presence of thioamides group in the prepared compounds. The possible reaction mechanism regarding the synthesis of the above mentioned compounds is discussed and its mechanism of corrosion inhibition in the corrosive environment was explained. The compounds was evaluated in brine and sea water, some compounds having percentage protection more than 50%, the results was compared with the imported commercial inhibitors and found to be compatible.

Keywords: Additives, corrosion inhibitors, market, brine