Synthesis, Structural Characterization, and Anti-corrosion Study of a New Fluorinated Bis-Schiff Base

A new series of bis-Schiff base compounds were synthesized. The fluorinated ketone (4-Biphenylyl trifluoromethyl ketone) was prepared by Friedel Crafts acylation of biphenyl as aromatic compound with trifluoroacetic anhydride in present (AlCl3) as a Lewis acid with very good yield. A bis-amine [1,1-bis(3-methyl-4-aminophenyl)-1-(4-biphenylyl)-2,2,2-trifluoroethane] was synthesized by refluxed of mixed fluorinated ketone, o-toluidine and o-toluidinehydrochloride to afforded the required bis-amine with a good yeild. The bis-Schiff bases were synthesized used bis-amine with several aldehydes (2-chlorobenzaldehyde, 4-chlorobenzaldehyde, 3-salicyldehyde, 5-nitrosalicyldehyde) into ethanol as a solvent and few drops of hydrochloric acid as catalyst with high yield. All compounds were confirmed by FTIR, 1HNMR, 13CNMR, Mass techniques. The compounds A3, A4, A5, and A6 exhibited high inhibition efficiency against steel corrosion in HCl solution, with values ranging from 87% to 94%. Compound A24 showed the highest performance, followed by A19, indicating the formation of a stable protective film that significantly reduces the corrosion rate.