Synthesis, Characterization, and Applications of Some New Trimeric-Type Cationic Surfactants

In recent years, trimeric surfactants have created excitement in the surfactant field because of their properties, which have been found to be better than monomeric or dimeric homologues. Only a limited number of trimeric surfactants have been synthesized and studied so far, probably owing to the difficulty in synthesis. In this article, we synthesized some novel star-shaped trimeric cationic surfactants based on the alkylation of the 3 hydroxyl groups of the phloroglucinol nuclei as a core (i.e., spacer) with 3 dodecyl or 3 octyl groups (as tails) for the surfactant. The chemical structures were confirmed by nuclear magnetic resonance, Fourier transform infrared, mass spectrometry, and elemental analysis; also the critical micelle concentration was determined by electrical conductivity measurements. These surfactants were used in the synthesis of mesoporous silica nanoparticles by the sol-gel method. The silica particles shape and size were determined using field emission scanning electron microscopy and high-resolution transmission electron microscopy images. Furthermore, the corrosion inhibitor capability of these surfactants was investigated by monitoring the corrosion rate of iron sheets in 0.5 M hydrochloric acid in the presence and in the absence of different surfactants at 45 degrees C based on the weight loss method. We have used cetyltrimethylammonium bromide (CTAB) as a positive control, the obtained results showed a high inhibition efficiency at very low concentrations, and the prepared trimeric surfactants exhibited a higher anticorrosion efficiency than the CTAB surfactants.