Tetrabutylammonium bromide (TBAB) is a quaternary ammonium salt with a bromide commonly used as a phase transfer catalyst. It is used to prepare many other tetrabutylammonium salts by salt metathesis reactions. The anhydrous form is a white solid.
In addition to being cheap, tetrabutylammonium bromide is also environmentally friendly, has a greater degree of selectivity, is operationally simple, non-corrosive, and can be recycled easily as well.
Tetrabutylammonium bromide can be prepared by the alkylation of tributylamine with 1-bromobutane.
Tetrabutylammonium bromide is used to prepare other salts of the tetrabutylammonium cation by salt metathesis reactions.
It serves as a source of bromide ions for substitution reactions. It is a commonly used phase transfer catalyst. As its melting point is just over 100 ðC and decreases in the presence of other reagents, it can be considered an ionic liquid.
TBAB is being extensively studied as a thermodynamic promoter in the formation of semi-clathrate hydrates which greatly brings down the pressure - temperature requirement for forming gas hydrates.