(1-Hexadecyl)trimethylammonium bromide is a cationic surfactant in hair conditioning products. It acts as a phase-transfer catalyst for the preparation of polyamide, polycarbonate and polythiocarbonate. It facilitates ligand-free palladium salt-catalyzed Heck and Suzuki cross-coupling reactions in water. It is an active component of the topical antiseptic cetrimide and used in household products such as shampoos and cosmetics. As a buffer solution, it is involved in the extraction of DNA as well as in the synthesis of gold nanoparticles and silican nanoparticles.