Tetrabutylammonium hydroxide

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Tetrabutylammonium hydroxide
CAS number 2052-49-5 YesY
PubChem 2723671
ChemSpider 2005872 YesY
Jmol-3D images Image 1
Molecular formula C16H37NO
Molar mass 259.47 g mol−1
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Tetrabutylammonium 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 is 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]


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]


  1. ^ 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.
  2. ^ Woodside, A. B.; Huang, Z.; Poulter, C. D. (1993), "Trisammonium Geranyl Diphosphate", Org. Synth. ; Coll. Vol. 8: 616 
  3. ^ Kuwajima, I.; Nakamura, E. Hashimoto, K. (1990), "Silylation of Ketones with Ethyl Trimethylsilacetate: (Z)-3-Trimethylsiloxy-2-Pentene", Org. Synth. ; Coll. Vol. 7: 512