Tetrapropylammonium hydroxide
[CAS# 4499-86-9]

Identification

• Classification: Chemical reagent >> Organic reagent >> Guanidine salt
• Name: Tetrapropylammonium hydroxide
• Molecular Formula: C₁₂H₂₈N.OH
• Molecular Weight: 203.37
• CAS Registry Number: 4499-86-9
• EC Number: 224-800-6
• SMILES: CCC[N+](CCC)(CCC)CCC.[OH-]

Properties

• Density: 0.99 g/mL (Expl.)
• Boiling point: 102 °C (Expl.)
• Refraction index: 1.372 (Expl.)

Safety Data

• Hazard Symbols: GHS05;GHS06;GHS07;GHS09 Danger
• Risk Statements: H302-H311-H314-H318-H411
• Safety Statements: P260-P262-P264-P264+P265-P270-P273-P280-P301+P317-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P321-P330-P361+P364-P363-P391-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Serious eye damage	Eye Dam.	1	H318
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Acute toxicity	Acute Tox.	3	H311
Acute toxicity	Acute Tox.	4	H302
Skin corrosion	Skin Corr.	1A	H314
Skin corrosion	Skin Corr.	1	H314

Discovery and Applications

Tetrapropylammonium hydroxide (TPAOH) is a quaternary ammonium salt composed of a tetrapropylammonium cation (C3H7)4N+ and a hydroxide anion (OH−). It is typically encountered as a solution, where it acts as a strong base due to the presence of the hydroxide anion. TPAOH is known for its high solubility in water and its ability to act as a strong nucleophile and base in chemical reactions.

The compound was developed as part of the broader interest in quaternary ammonium salts, which have found applications in a variety of chemical processes, including catalysis, phase transfer reactions, and organic synthesis. Quaternary ammonium salts, including tetrapropylammonium hydroxide, have been widely studied due to their ability to dissolve in both organic and aqueous solvents, facilitating a range of reactions.

Tetrapropylammonium hydroxide is primarily used in organic synthesis, where it serves as a strong base for deprotonation reactions. It is particularly useful in reactions that involve the generation of nucleophiles or the formation of enolates, as the hydroxide ion is highly reactive and capable of deprotonating weak acids. One common application is in the formation of enolates from carbonyl compounds, which can then be used in subsequent reactions, such as aldol condensations or Michael additions. In these reactions, TPAOH helps to generate the nucleophilic enolate, which is critical for the success of these transformations.

In addition to its role in organic synthesis, tetrapropylammonium hydroxide is also utilized in the preparation of certain types of fluorinated compounds. The hydroxide ion, being a strong base, is capable of promoting the elimination of halide ions from organic substrates, facilitating the formation of carbon-carbon bonds or the introduction of other functional groups. This property is especially useful in the synthesis of compounds that require the formation of reactive intermediates or in reactions that involve the introduction of new chemical bonds.

Furthermore, TPAOH is used in phase transfer catalysis, a process in which a catalyst is used to facilitate the transfer of a reactant between two immiscible phases, such as an aqueous phase and an organic phase. In phase transfer catalysis, the tetrapropylammonium cation helps to solvate the hydroxide anion, allowing it to efficiently transfer from one phase to another. This ability to promote the transfer of hydroxide ions across phase boundaries is valuable in a variety of chemical reactions, including those that involve nucleophilic substitution or elimination processes.

Another notable application of tetrapropylammonium hydroxide is in the production of certain specialty chemicals and materials, including surfactants, detergents, and polymer precursors. The reactivity of the hydroxide ion in TPAOH makes it useful for modifying or functionalizing various substrates, which is crucial in the development of novel materials with unique properties.

While TPAOH is useful in many chemical processes, it should be handled with caution. As with other strong bases, it can cause chemical burns and irritation to the skin, eyes, and mucous membranes. Appropriate safety measures, including the use of gloves, goggles, and fume hoods, should be observed when handling TPAOH. Furthermore, the compound is hygroscopic, meaning it readily absorbs moisture from the air, and should be stored in a dry environment to maintain its stability.

In summary, tetrapropylammonium hydroxide is a quaternary ammonium salt with significant applications in organic synthesis, phase transfer catalysis, and the preparation of specialty chemicals. Its ability to act as a strong base and facilitate nucleophilic reactions makes it a valuable reagent in a variety of chemical processes. The continued use of TPAOH in research and industry underscores its importance in modern synthetic chemistry.

References

2024 Collaborative role of seed solution and CTAB in the synthesis of hierarchical ZSM-5 zeolites and their templating mechanism. Journal of Porous Materials, 1, 1. DOI: 10.1007/s10934-024-01722-5

2024 Pt-xCe nanoparticles confined within HZSM-5 for increasing the selectivity of light olefins in iso-butane cracking. Journal of Porous Materials, 1, 1. DOI: 10.1007/s10934-024-01683-9

2024 Recent Advancements of SAPO-34 and ZSM-5 Zeolite in Converting Methanol to Olefin: A Review. Arabian Journal for Science and Engineering, 1, 1. DOI: 10.1007/s13369-024-09786-w