1-Bromooctadecane is primarily used as an alkylating agent in organic synthesis, where it introduces long-chain alkyl groups into various compounds. It is commonly employed in the production of surfactants and detergents, enhancing their cleaning properties by modifying their hydrophobic and hydrophilic balance. This chemical is also utilized in the synthesis of quaternary ammonium compounds, which are widely applied as disinfectants, fabric softeners, and phase transfer catalysts. Additionally, it serves as a precursor in the preparation of other organic molecules, including pharmaceuticals and specialty chemicals, where its long carbon chain contributes to desired physical and chemical properties. In research, it is often used to study reaction mechanisms involving alkyl halides or to create model compounds for material science applications.