Tetrabutylammonium fluoride trihydrate
[CAS# 87749-50-6]

Identification

• Classification: Chemical reagent >> Fluorine reagent
• Name: Tetrabutylammonium fluoride trihydrate
• Molecular Formula: C₁₆H₃₆FN.3(H₂O)
• Molecular Weight: 315.51
• CAS Registry Number: 87749-50-6
• EC Number: 618-063-3
• SMILES: CCCC[N+](CCCC)(CCCC)CCCC.O.O.O.[F-]

Properties

• Melting point: 58-60 °C
• Water solubility: SOLUBLE

Safety Data

• Hazard Symbols: GHS05 Danger
• Risk Statements: H314-H318
• Safety Statements: P260-P264-P264+P265-P280-P301+P330+P331-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P321-P363-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1C	H314
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H302
Skin irritation	Skin Irrit.	2	H315
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412

• Transport Information: UN 1759

Discovery and Applications

Tetrabutylammonium fluoride trihydrate (TBAF·3H2O) is a quaternary ammonium salt, recognized for its utility in organic synthesis and various chemical applications. First synthesized in the mid-20th century, TBAF was developed as a versatile fluoride source. The compound is typically produced by neutralizing tetrabutylammonium hydroxide with hydrofluoric acid, leading to the formation of TBAF along with water. The trihydrate form includes three water molecules per TBAF unit, enhancing its solubility and handling properties.

The structure of TBAF·3H2O consists of a tetrabutylammonium cation and a fluoride anion, associated with water molecules that facilitate solubility in polar solvents. This ionic composition contributes to its effectiveness as a fluoride source in various chemical reactions. The use of TBAF in organic synthesis primarily stems from its ability to provide fluoride ions, which play a critical role in nucleophilic substitution reactions, as well as in deprotecting certain functional groups.

One of the most significant applications of TBAF is in the removal of silyl protecting groups in the synthesis of complex organic molecules. Silyl groups, such as trimethylsilyl (TMS) groups, are often used to protect hydroxyl and amine functionalities during multi-step syntheses. TBAF efficiently cleaves these protective groups, allowing for the subsequent functionalization of the underlying hydroxyls or amines. This deprotection ability is particularly valuable in the fields of medicinal chemistry and natural product synthesis, where complex molecular architectures require selective functionalization.

Additionally, TBAF is employed in the synthesis of organofluorine compounds, which have garnered significant interest in pharmaceuticals, agrochemicals, and materials science. The introduction of fluorine atoms into organic molecules can modify their biological activity, improve metabolic stability, and enhance lipophilicity. TBAF serves as a reliable and mild fluorinating agent, facilitating the synthesis of fluorinated intermediates and final products.

Beyond organic synthesis, TBAF is also utilized in polymer chemistry. It can act as a catalyst in the polymerization of certain monomers and in the modification of polymers to improve their properties. For example, TBAF has been investigated for its role in the synthesis of fluorinated polymers, which exhibit unique thermal and chemical stability.

In analytical chemistry, TBAF has found applications as a reagent for the determination of silicon and other elements. Its ability to release fluoride ions makes it useful in specific analytical procedures where fluoride reactivity is necessary.

Despite its usefulness, caution is advised when handling TBAF·3H2O due to its reactivity and potential hazards associated with fluoride exposure. Proper safety protocols should be observed in laboratory environments to mitigate risks related to inhalation or skin contact.

In summary, tetrabutylammonium fluoride trihydrate is a valuable compound with a range of applications in organic synthesis, polymer chemistry, and analytical methods. Its ability to provide fluoride ions in a controlled manner makes it an essential reagent in various chemical processes, contributing to advancements in synthetic methodologies and the development of new materials.

References

2024 Regenerated Cellulose. Review. Part 2. Pretreatment of Cellulose. Technologies for Producing Regenerated Cellulose. Polymer Science, Series D, 1, 1120.
DOI: 10.1134/s1995421224701120

2024 Regenerated Cellulose. Review. Part 1. Cellulose Structure, Solvent Systems, and Dissolution Mechanisms. Polymer Science, Series D, 1, 801.
DOI: 10.1134/s1995421224700801

2023 Experimental Study of the Rate of Methane Hydrate Formation: Influence of Simultaneous Utilization of Tetra n-Butylammonium Fluoride and Sodium Dodecyl Sulfate. Solid Fuel Chemistry, 1, 7005.
DOI: 10.3103/s0361521923070054