Tetraethylammonium hydrogencarbonate is commonly used as a phase-transfer catalyst in organic synthesis, facilitating reactions between substances in different phases, such as aqueous and organic layers. It is particularly effective in nucleophilic substitution reactions, where it helps transfer anions from the aqueous phase to the organic phase, enhancing reaction rates and yields. Additionally, it finds application in electrochemical studies as an electrolyte additive, improving the conductivity and stability of electrolytes in various electrochemical systems. Its role in the preparation of ionic liquids and as a stabilizer in certain chemical processes further highlights its versatility in industrial and research settings.