4-Aminoantipyrine derived cationic surfactants: Synthesis, characterization, surface activity and screening for potential antimicrobial activities

A series of cationic surfactants were synthesized from chemical modification of 4-aminoantipyrine. The chemical structures were confirmed using infrared (FTIR) and nuclear magnetic resonance (1H NMR) spectroscopy. The surface activities of the surfactants in their solutions were determined by surface tension measurements. Increasing the hydrophobic chain length increased the surface activity of the surfactants in solutions. Measurements of interfacial tension between surfactants solutions and light paraffin oil showed that the interfacial tension values were decreased with increasing the alkyl chain length. The emulsion stability measurements showed the applicability of these surfactants as emulsifying agents. The foaming power measurements showed the synthesized surfactants have low ability for foam formation. Thermodynamic properties of adsorption and micellization processes showed their tendency towards adsorption at solution interface and micellization in their solutions. Results showed reasonable surface activities compared to conventional cationic surfactants. The antimicrobial activity of the synthesized surfactants against Gram-positive bacteria (Bacillus subtilis and Staphyl. aureus, Gram-negative bacteria (Pseudomonas aeruginosa and E. coli.) and Fungi (Candida albicans and Aspergillus niger) was evaluated. The efficiency of these compounds as antimicrobial agents) was increased with the hydrophobicity and carbon chain length.