Tetrabutylammonium bromide (TBAB) is a

quaternary ammonium salt In organic chemistry, quaternary ammonium cations, also known as quats, are positively-charged polyatomic ions of the structure , where R is an alkyl group, an aryl group or organyl group. Unlike the ammonium ion () and the primary, secondary, ...

with a

bromide A bromide ion is the negatively charged form (Br−) of the element bromine, a member of the halogens group on the periodic table. Most bromides are colorless. Bromides have many practical roles, being found in anticonvulsants, flame-retard ...

commonly used as a

phase transfer catalyst In chemistry, a phase-transfer catalyst or PTC is a catalyst that facilitates the transition of a reactant from one phase into another phase where reaction occurs. Phase-transfer catalysis is a special form of catalysis and can act through homog ...

. It is used to prepare many other

tetrabutylammonium Tetrabutylammonium is a quaternary ammonium cation with the formula , also denoted (where Bu = butyl group). It is used in the research laboratory to prepare lipophilic salts of inorganic anions. Relative to tetraethylammonium derivatives, tetr ...

salts by

salt metathesis A salt metathesis reaction (also called a double displacement reaction, double replacement reaction, or double decomposition) is a type of chemical reaction in which two ionic compounds in aqueous solution exchange their component ions to form two ...

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.

Preparation and reactions

Tetrabutylammonium bromide can be prepared by the alkylation of

tributylamine Tributylamine (TBA) is an organic compound with the molecular formula (C4H9)3N. It is a colorless liquid with an amine-like odor. Uses Tributylamine is used as a catalyst (proton acceptor) and as a solvent in organic syntheses and polymerization ...

with 1-bromobutane. Tetrabutylammonium bromide is used to prepare other salts of the tetrabutylammonium cation by

salt metathesis reaction A salt metathesis reaction (also called a double displacement reaction, double replacement reaction, or double decomposition) is a type of chemical reaction in which two ionic compounds in aqueous solution exchange their component ions to form two ...

s. It serves as a source of

ions for substitution reactions. It is a commonly used

. As its melting point is just over 100 °C and decreases in the presence of other reagents, it can be considered an

ionic liquid An ionic liquid (IL) is a salt (chemistry), salt in the liquid state at ambient conditions. In some contexts, the term has been restricted to salts whose melting point is below a specific temperature, such as . While ordinary liquids such as wate ...

Role in semi-clathrate formation

TBAB is being extensively studied as a thermodynamic promoter in the formation of semi-

clathrate A clathrate is a chemical substance consisting of a lattice (group), lattice that traps or contains molecules. The word ''clathrate'' is derived from the Latin language, Latin (), meaning 'with bars, Crystal structure, latticed'. Most clathrate ...

hydrates which greatly brings down the pressure - temperature requirement for forming gas hydrates.

References

{{reflist Tetrabutylammonium salts

Preparation and reactions

Role in semi-clathrate formation

See also

References