Tetrapropyl ammonium chloride
[CAS# 5810-42-4]

Identification

• Classification: Chemical reagent >> Organic reagent >> Amine salt (ammonium salt)
• Name: Tetrapropyl ammonium chloride
• Synonyms: Tetrapropylammonium chloride
• Molecular Formula: C₁₂H₂₈N.Cl
• Molecular Weight: 221.81
• CAS Registry Number: 5810-42-4
• EC Number: 227-375-5
• SMILES: CCC[N+](CCC)(CCC)CCC.[Cl-]

Properties

• Solubility: soluble (water, acetone) (Expl.)
• Melting point: 240-242 °C (Expl.)

Safety Data

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

Hazard Classification

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

Discovery and Applications

Tetrapropyl ammonium chloride (TPAC) is a quaternary ammonium salt with the chemical formula [(C3H7)4N]Cl. It consists of a nitrogen atom (N) bonded to four propyl groups (C3H7) and a chloride ion (Cl⁻). As a member of the larger class of quaternary ammonium compounds, TPAC is widely used in both industrial and laboratory applications. It is particularly valued for its role in facilitating chemical reactions through phase-transfer catalysis, among other uses.

The primary function of tetrapropyl ammonium chloride is as a phase-transfer catalyst. Phase-transfer catalysis is a process in which a catalyst facilitates the transfer of reactants between two immiscible phases, typically an aqueous phase and an organic phase. This is particularly useful in reactions involving ionic species that have limited solubility in either phase. TPAC helps to bridge the solubility gap by enabling the ionic compounds to dissolve in the organic phase, which enhances the efficiency and rate of chemical reactions. Phase-transfer catalysts like TPAC have numerous applications in organic synthesis, where they play a crucial role in reactions such as nucleophilic substitution, coupling reactions, and halogenation.

For example, TPAC is often used in the synthesis of complex organic molecules, including the production of pharmaceuticals, agrochemicals, and other fine chemicals. Its ability to mediate the transfer of anionic species between immiscible solvents makes it particularly effective in facilitating reactions where conventional methods may be inefficient or slow. By improving the solubility of reactants, TPAC can significantly increase reaction yields and reduce the need for excess reagents or energy input.

Beyond its catalytic function, tetrapropyl ammonium chloride is also employed as a surfactant. Surfactants are compounds that lower the surface tension of liquids, allowing them to spread more easily or mix with other substances. TPAC's surfactant properties make it valuable in a range of applications, including the stabilization of emulsions, the formulation of cleaning products, and the production of paints and coatings. In these applications, TPAC acts to stabilize mixtures of water and oils or other hydrophobic substances, ensuring the consistency and effectiveness of the product.

Tetrapropyl ammonium chloride is also used in the synthesis of other quaternary ammonium compounds. In these processes, it can serve as a precursor or intermediate in the production of more complex compounds that have specialized applications. Quaternary ammonium compounds are commonly used in a variety of fields, including water treatment, disinfection, and as surfactants in personal care products such as shampoos, body washes, and lotions. TPAC's role as a precursor in the production of other ammonium-based chemicals further underscores its versatility in industrial chemistry.

In terms of safety, tetrapropyl ammonium chloride, like many quaternary ammonium salts, is considered to be moderately toxic. Direct exposure to the substance can cause irritation to the skin, eyes, and respiratory system. As a result, it is essential to handle TPAC with care, using appropriate protective equipment such as gloves, goggles, and face masks when working with the compound. Additionally, care must be taken to ensure proper ventilation when using TPAC in laboratory or industrial settings to avoid inhalation of its vapors or dust.

While TPAC is a relatively stable compound under standard conditions, it can decompose at elevated temperatures, releasing toxic gases. Therefore, it is crucial to store tetrapropyl ammonium chloride in a cool, dry place and to follow recommended safety guidelines to minimize risks associated with its use.

Tetrapropyl ammonium chloride's versatility as a phase-transfer catalyst, surfactant, and precursor for other quaternary ammonium compounds has made it a valuable tool in both industrial and laboratory settings. Its primary application in phase-transfer catalysis allows it to enhance the efficiency of chemical reactions, particularly those involving ionic species. As a surfactant, TPAC contributes to the formulation of stable emulsions and cleaning products. Furthermore, it plays a role in the synthesis of other quaternary ammonium compounds, expanding its utility in various sectors. Despite its usefulness, proper safety precautions are necessary to ensure safe handling and minimize exposure to this moderately toxic substance.

In summary, tetrapropyl ammonium chloride is a compound with a wide range of applications in organic chemistry and industry. Its ability to act as a phase-transfer catalyst and surfactant makes it essential in numerous chemical processes, while its role as a precursor for other quaternary ammonium compounds further expands its importance. With proper handling and safety precautions, TPAC remains a valuable and versatile substance in modern chemical synthesis and industrial formulations.

References

2023. Tetraalkylammonium Chlorides as Melting Point Depressants of Ionic Liquids. Journal of Solution Chemistry, 52(6).
DOI: 10.1007/s10953-023-01285-0

2022. Modelling of Mean Ionic Activity and Osmotic Coefficients in Aqueous Solutions of Symmetrical Tetra alkyl Ammonium Halides. Journal of Solution Chemistry, 51(11).
DOI: 10.1007/s10953-022-01211-w