Tributylmethylammonium bromide
[CAS# 37026-88-3]

Identification

• Classification: Chemical reagent >> Organic reagent >> Amine salt (ammonium salt)
• Name: Tributylmethylammonium bromide
• Synonyms: Methyltributylammonium bromide
• Molecular Formula: C₁₃H₃₀BrN
• Molecular Weight: 280.29
• CAS Registry Number: 37026-88-3
• EC Number: 253-313-1
• SMILES: CCCC[N+](C)(CCCC)CCCC.[Br-]

Properties

• Melting point: 120-122 ºC (Expl.)

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319-H335
• Precautionary Statements: P261-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319

Discovory and Applicatios

Tributylmethylammonium bromide (C12H27BrN) is a quaternary ammonium salt composed of a nitrogen atom bonded to three butyl groups and a methyl group, with a bromide anion (Br-) as the counterion. It is commonly synthesized by reacting methyl iodide with tributylamine in the presence of a base, such as potassium hydroxide. The product is a crystalline solid that is soluble in polar organic solvents like acetone and ethanol but insoluble in water due to its nonpolar characteristics.

This compound has gained significant attention in the field of organic chemistry and industrial applications due to its role as a phase-transfer catalyst. Phase-transfer catalysts (PTCs) are a class of compounds that facilitate the migration of reactants between immiscible phases, which is essential for reactions involving a solid phase and a liquid phase, or two immiscible liquids. These catalysts work by increasing the reactivity of ionic or polar reactants in nonpolar solvents, where they are typically insoluble. PTCs, such as tributylmethylammonium bromide, can enhance the efficiency of a variety of chemical reactions, particularly nucleophilic substitution reactions.

In nucleophilic substitution reactions, the nucleophile must interact with an electrophile to replace a leaving group. However, in many cases, the nucleophile is soluble in water, while the electrophile is in an organic phase. Tributylmethylammonium bromide facilitates the transfer of the nucleophile (anions, for example) from the aqueous phase to the organic phase, where it can then react with the electrophile. This significantly speeds up reactions that would otherwise be slow or inefficient, particularly in reactions such as halogen exchange or esterification.

The compound is widely utilized in the preparation of various chemical intermediates and materials. For example, it is used in the synthesis of surfactants, where its amphiphilic nature, due to the presence of the bulky butyl groups, makes it effective in lowering surface tension between different phases. This makes it useful in applications such as detergents, emulsifiers, and stabilizers for various colloidal systems. Moreover, tributylmethylammonium bromide has been employed in polymer chemistry, particularly in the synthesis of polymers and resins, where it helps in initiating or accelerating polymerization processes.

One of the notable uses of tributylmethylammonium bromide is in the preparation of the alkylation of nucleophiles such as alcohols, phenols, and thiols, with electrophiles such as alkyl halides. In the case of reactions involving alkyl halides, the ammonium salt serves as a catalyst to facilitate the exchange of halide ions, which are typically unreactive, with more reactive nucleophiles. The compound has been utilized in the preparation of various fine chemicals, including pharmaceuticals, fragrances, and other specialty chemicals.

Beyond its role in organic synthesis, tributylmethylammonium bromide is used in the extraction of heavy metals and other ions from aqueous solutions. It has been employed to enhance the solubility of certain metal complexes, improving the efficiency of metal extraction processes in both laboratory and industrial settings. Additionally, it has been used in ion-exchange chromatography as a mobile phase additive to alter the solubility of certain compounds.

In industry, tributylmethylammonium bromide is particularly valued for its ability to enable reactions that are otherwise difficult or inefficient in aqueous or organic solvents alone. It serves as an effective and versatile catalyst for a wide range of synthetic applications, especially in processes requiring phase transfer or the combination of polar and nonpolar components. In the laboratory, it has become an essential reagent for facilitating reactions in both academic and industrial research settings.

While tributylmethylammonium bromide is stable under normal conditions, it is crucial to handle the compound with care. Like many quaternary ammonium salts, it can be toxic if ingested or inhaled, and it should be stored in airtight containers to prevent degradation. Safety precautions must be followed during its use, particularly when working with concentrated solutions or in large-scale applications.

In summary, tributylmethylammonium bromide is a highly useful compound in organic chemistry and industrial processes, owing to its ability to facilitate phase-transfer catalysis. Its role in increasing the reactivity and efficiency of a wide range of chemical reactions, such as nucleophilic substitutions, esterifications, and alkylations, makes it invaluable in both research and industrial settings. Furthermore, its applications extend to polymer synthesis, extraction processes, and the production of chemical intermediates, demonstrating its versatility and importance in chemical synthesis and material production.

References

1979 Hydrophobic hydration of some different types of quaternary ammonium bromides in mixtures of water and N,N-dimethylformamide. Journal of Solution Chemistry, 8, 1.