Tetrabutylammonium iodide is a quaternary ammonium salt phase transfer catalyst.Its pure form is a white hygroscopic crystal or powder with the molecular formula C₁₆H₃₆IN.It is stable under normal temperature and pressure, but sensitive to light and moisture, so it should be sealed and stored under inert gas and protected from light.As an organic cationic iodide salt, it has good ionic conductivity and lipophilicity, and is widely used in organic synthesis, electrochemistry and catalysis.

1. Phase transfer catalyst for organic synthesis: Promotes aqueous-organic two-phase reactions (e.g., nucleophilic substitution, oxidation, reduction), improving reaction rate and selectivity.

2. Intermediate for pharmaceuticals and dyes: Used as an alkylating agent and ion-pair reagent in drug synthesis and dye preparation.

3. Electrochemical applications: Used in electrolytes, ion-conductive materials, and battery electrolyte additives.

4. Chemical analysis: Serves as an ion-pair reagent and chromatographic additive to enhance the separation of polar compounds.

5. Polymerization reactions: Acts as an initiator and stabilizer in polymer polymerization.