Abstract
Many organic compounds having electron-rich atoms in their structure, such as nitrogen and sulfur, are widely in use as lubricating additives in the oil industry to minimize corrosion. The presence of electron-rich atoms in the molecules of compounds under discussion increases the ability of these substances to form coordinate covalent bonds with the metal atoms involved in the corrosion environment.
Compounds based on fatty amine, aromatic amine, imidazoline, di-imidazoline, and fatty amide are widely used as corrosion inhibitors. Less attention has been given to studying thiocarboxylic acid amides as corrosion inhibitors, particularly in the oil field.
In this work, some phenylacetothioamide and benzylacetothioamide are synthesized. The chemical and physical data of the prepared compounds are compiled. The solubility, cold stability, heat stability, and corrosion inhibition characteristics of the synthesized compounds have been measured in the artificial environment (10% crude in artificial brine at the pH between 4.5 to 4.8). Anticorrosive properties for a few of the amine-based commercially available oilfield corrosion inhibitors and a few of the above-mentioned synthesized compounds are measured in the test environment to compare their activity. Prepared thioamides differ in their molecular weights due to the presence of different organic substituents on the thioamide group. The synthesis of the above-mentioned compounds is based on the Willgerodt-Kindler reaction.
The synthesized compounds are confirmed by IR, UV/Vis, Elemental Analyzer, and other traditional analytical techniques. The experimental values of the elemental composition of these compounds were compared with the calculated values and found to be in agreement. UV/Vis and IR spectra also show the absorption peaks, which confirm the presence of thioamide groups in the prepared compounds. The possible reaction mechanism regarding the synthesis of the above-mentioned compounds is discussed. The mechanism of corrosion inhibition of these compounds in the corrosive environment is explained.