Benzothiazol-3-ium Cationic Schiff Base Surfactants: Synthesis, Surface Activity and Antimicrobial Applications against Pathogenic and Sulfur Reducing Bacteria in Oil Fields

Abstract

Two series of cationic Schiff base surfactants namely: 2-(benzylideneamino)-3-(2-oxo-2-alkoxyethyl)-1,3-benzothiazol-3-ium bromide (1-4) and 2-[(4-methoxybenzylidene)amino]-3-(2-oxo-2-alkoxyethyl)-1,3-benzothiazol-3-ium bromide (5-8) were prepared. The chemical structures of the prepared Schiff bases were recognized by elemental analysis, FTIR, and NMR spectra. The surface activities of the synthesized Schiff base cationic surfactants were showed their tendency towards adsorption at the air/water interface. The adsorption tendency was estimated from the values of surface tension and the depression of surface tension at the CMC. The studied surfactants were evaluated as antimicrobial agents against pathogenic and sulfur reducing bacteria using inhibition zone technique. The synthesized cationic pyrazolium Schiff base surfactants showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative and fungi. The promising inhibition efficiency of these compounds against the sulfur reducing bacteria facilitates them to be applicable in the petroleum field as new categories of SRB biocides.