Tetraheptylammonium bromide (>98%, BC) (THAB) is a quaternary ammonium compound often used as a phase transfer catalyst in organic synthesis reactions, especially those involving charged substances or polar reagents. It facilitates the transfer of reactants between two immiscible phases, such as water and organic solvents, by forming stable ion pairs. Additionally, THAB serves as a surfactant and an additive in various products like cosmetics, pharmaceuticals, and detergents. Its ability to complex with ions has also been explored for potential applications in removing heavy metal ions from wastewater.