Tetrabutylammonium hydroxide

General
Tetrabutylammonium hydroxide
Chemical name Tetrabutylammonium hydroxide
Chemical formula	C₁₆H₃₇NO
Molecular weight	259.47 g/mol
Appearance	Colourless to light yellow solution
CAS number	2052-49-5
MSDS	Tetrabutylammonium hydroxide MSDS
SMILES	?
Other names	TBAOH
Physical properties
Solubility	water, methanol
Density	0.97 g/cm³ (for solution 55% w/w at 20 °C)
pH (10% solution with water)	?
Phase behavior
Melting point	not obtainable as pure species
Boiling point	decomp
Safety
Ingestion	Damage to the digestive tract.
Inhalation	burns to the respiratory tract.
Skin	burns.
Eyes	burns.
Precautions
Hazards: corrosive (class 8) Personal protection:
Solid properties
Except where noted, all data was produced under conditions of standard temperature and pressure.

Tetrabutyl ammonium hydroxide is the chemical compound with the formula (C₄H₉)₄NOH, abbreviated Bu₄NOH with the acronym TBAOH or TBAH. This species is not readily obtainable as a pure compound, but it employed as a solution in water or alcohols. It is commonly used as a base in organic chemistry. Relative to more conventional inorganic bases, such as KOH and NaOH, Bu₄NOH is more soluble in organic solvents. Attempted isolation of pure Bu₄NOH induces Hofmann elimination, leading to Bu₃N and 1-butene. Solutions of Bu₄NOH are typically contaminated with Bu₃N for this reason.^[1]

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Applications in the synthesis of organic compounds

Bu₄NOH is a strong base that is used often under phase-transfer conditions to effect alkylations and deprotonations. Typical reactions include benzylation of amines and generation of dichlorocarbene from chloroform.

Bu₄NOH can be neutralized with a variety of mineral acids to give lipophilic salts of the conjugate base. For example, treatment of Bu₄NOH with disodium pyrophosphate, Na₂H₂P₂O₇, gives (Bu₄N)₃[HP₂O₇], which is soluble in organic solvents.^[2] Similarly, neutralization of Bu₄NOH with hydrofluoric acid affords Bu₄NF. This salt dissolves in organic solvents and is useful to desilylation.^[3]

Safety

Bu₄NOH is toxic and corrosive. See MSDS.

References

^ Bos, M. E. "Tetra-n-butylammonium Hydroxide" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
^ Woodside, A. B.; Huang, Z.; Poulter, C. D. “Trisammonium Geranyl Diphosphate” Organic Syntheses, Collected Volume 8, p.616 (1993). http://www.orgsyn.org/orgsyn/pdfs/CV8P0616.pdf
^ Kuwajima, I.; Nakamura, E. Hashimoto, K. “Silylation of Ketones with Ethyl Trimethylsilacetate: (Z)-3-Trimethylsiloxy-2-Pentene” Organic Syntheses, Collected Volume 7, p.512 (1990). http://www.orgsyn.org/orgsyn/pdfs/CV7P0512.pdf

Category: Quaternary ammonium compounds

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Tetrabutylammonium_hydroxide". A list of authors is available in Wikipedia.