Tetra Butyl Ammonium Iodide (TBAI)

The chemical formula for tetra butyl ammonium iodide (TBAI), a quaternary ammonium salt, is C₁₆H₃₆NI.

 

It is combined with iodine to create tetra butyl ammonium triiodide. It is commonly used in various chemical processes, particularly in organic synthesis and catalysis, due to its ability to act as a phase-transfer catalyst.

 

  • Properties

Tetra-n-butylammonium iodide is a solid crystal that belongs to the monoclinic crystal system. Space group C2/c is present. The unit cell’s dimensions are β = 111.149, a = 14.2806, b = 14.1864, and c = 19.5951. The volume of the unit cell (Z=8), which has eight formulas, is 3702.4 Å3.

 

Tetra-n-butylammonium iodide has a lower enthalpy of formation (ΔfH0) than either bromide or chloride (−540, −564 kJ/mol), at -499 kJ/mol.

 

With water, tetra-n-butylammonium iodide produces a clathrate hydrate at lower temperatures. The hydrophobic tetra-n-butylammonium cation is big. The gas phase’s absolute enthalpy of hydration is -260 kJ/mol.

 

The tetra-n-butylammonium cation is responsible for a peak at 11 eV in the He(I) photoelectron spectra of tetra-n-butylammonium iodide, whereas the iodide is responsible for peaks at 7 and 8 eV.

Physical and Chemical Properties of Tetra Butyl Ammonium Iodide

1. Appearance: White to pale yellow crystalline powder or solid

 

2. Molecular Formula: C₁₆H₃₆NI

 

3. Molecular Weight: 369.37 g/mol

 

4. Melting Point: Approximately 150-160°C (can vary slightly depending on purity)

 

5. Solubility: Soluble in water and various organic solvents like methanol, ethanol, acetonitrile, and dimethyl sulfoxide (DMSO)

 

6. Density: Typically around 1.1 g/cm³ (varies with temperature and form)

 

7. Boiling Point: Decomposes before boiling, so no boiling point is typically listed

 

8. Odor: Odorless

Tetra Butyl Ammonium Iodide
Applications of Tetra Butyl Ammonium Iodide

1. Phase-Transfer Catalysis:

 

Organic Synthesis: TBAI is widely used as a phase-transfer catalyst in organic chemistry. It facilitates the reaction between ionic compounds in different phases, such as aqueous and organic phases, by transferring one reactant from one phase into another where the reaction occurs.

 

2. Halogenation Reactions:

 

Iodination: TBAI is particularly useful in halogenation reactions, where it helps to introduce iodine into organic compounds. This is important in synthesizing various iodinated organic compounds used in pharmaceuticals and other industries..

 

3. Electrochemistry:

 

Conductivity: Due to its ionic nature, TBAI is sometimes used in electrochemical applications, such as in the preparation of electrolytes for batteries and other electrochemical cells.

 

4. Pharmaceutical Industry:

 

Drug Synthesis: TBAI can be used in the synthesis of pharmaceutical intermediates and active pharmaceutical ingredients (APIs), especially where iodination is a key step in the reaction process.

 

5. Catalysis:

 

As a Catalyst: TBAI can act as a catalyst in various chemical reactions, including nucleophilic substitutions and other transformations that require the presence of an iodide ion.