Used as a phase-transfer catalyst in organic synthesis, facilitating reactions between compounds in different phases by transferring ions into organic solvents. Employed in the preparation of quaternary ammonium salts for surfactants and disinfectants. Acts as an electrolyte in electrochemical applications and in the formulation of ion-selective electrodes. Also utilized in neuroscience research to block potassium channels in cell membranes, aiding in the study of nerve conduction and muscle contraction.