Tetra-n-butylammonium bromide
Tetra-n-butylammonium bromide is a quaternary ammonium salt with a bromide counterion 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.Preparation
Tetra-n-butylammonium bromide can be prepared by the nucleophilic substitution reaction of tri-n-butylamine with n-butyl bromide.Tetra-n-butylammonium bromide is used to prepare other salts of the tetrabutylammonium cation by salt metathesis reactions, and acts as a source of nucleophilic bromide ions for substitution reactions. It is one of the most commonly-used phase transfer catalysts. As its melting point is just over 100 °C and decreases in the presence of other reagents, it can be considered an ionic liquid. As an ionic liquid, it might be used as a solvent in various reactions, for instance cross-coupling reactions.
