Synthesis, characterization, interaction with anionic dye, biodegradability, and antimicrobial activity of cationic surfactants: quaternary hydrazinium derivatives

A novel cationic surfactant type of N'alkyl N,'N'dimethyl-4-morpholino-4-oxobutanoylhydrazinium iodide (10a–12a) and N'alkyl N', N'dimethyl-4-piperidino-4-oxobutanoylhydrazinium iodide (10b–12b) of quaternary hydrazinium moieties in hydrophilic parts was synthesized. These quaternary hydrazinium surfactants were obtained using a two-step reaction scheme, starting from ring opening of succinic anhydride with a base (morpholine, piperidine), followed by ammonolysis with hydrazine hydrate, then alkylation of the amino group with alkyl bromides (RBr) that have different hydrophobic chain lengths (R, C12H25, C14H29, and C16H37), and ending with the quaternarization of the secondary amino group by two moles of methyl iodide. The chemical composition of the surfactants was analyzed by FTIR, 1HNMR, mass spectroscopy, and elemental analysis. A variety of surface-active characteristics were achieved by surface calculations, including CMC, γcmc, CMC/C20, Γmax, pC20, Amin, and Πcmc. These surface characteristics and foam stability rely on the nature of the hydrophobic chain. Preliminary results showed that an upgrade throughout the CH2 group in the fatty chain and the morpholine or piperidine ring lowers the CMC and increases the foaming capacity and stability of the quaternary hydrazinium surfactants. Anionic dye (Acid BG) interactions with 12b surfactant (as an example) were studied using the spectrophotometric technique and the binding constant (170.64 dm3.mol−1) was determined. The results indicate solubilization and binding took place at a large scale. Furthermore, considerable biodegradation of cationic surfactants was observed (68–87%). The antimicrobial activity of these surfactants has also been observed with the minimum inhibitory concentration (MIC) and the size of inhibited growth zone. The smallest MICs were found in 12a (64 µg/mL) and 12b (32 µg/mL) surfactants, indicating the highest antimicrobial activity.