Cesium carbonate

Description

Cesium carbonate is a basic carbonate and is used in organic synthesis as a mild inorganic base. It can be used in C, N, O alkylation and arylation reactions. Cesium carbonate not only promotes the carbonylation of alcohols and carbamination of amines but also inhibits side reactions common in other processes. It is also used in six-membered annulation, intramolecular and intermolecular cyclizations, Suzuki coupling, aza-Henry, nucleophilic substitution, cross-coupling and different cycloaddition reactions. 

Chemical properties

Colourless crystals or white powder , easily soluble in water, quickly absorbs moisture when placed in the air. The aqueous solution of cesium carbonate is strongly alkaline and can react with acid to produce the corresponding cesium salt and water, and release carbon dioxide. One of the biggest advantages of cesium carbonate (Cs2CO3) is that it has a higher solubility in most solvents than K2CO3 or Na2CO3.

The Uses of Cesium carbonate

Cesium carbonate is a versatile reagent for organic synthesis. It has also found use as a catalyst for ethylene oxide polymerization, in coating for spatter-free welding of steel in CO2, as a functional interlayer in photovoltaic devices and in oxide cathodes. Cesium carbonate is also used in the beer-brewing industry to make the "head" of beer foamier. Cesium carbonate is useful in the N-alkylation (of sulfonamides, beta-lactams, indoles, heterocycles and several sensitive nitrogen compounds), carbamination of amines, carbonylation of alcohols and aerobic oxidation of alcohols into carbonyl compounds without polymeric by products.

Preparation

cesium carbonate can be prepared by thermal decomposition of caesium oxalate. Upon heating, caesium oxalate is converted to caesium carbonate with emission of carbon monoxide.
Cs2C2O4 → Cs2CO3 + CO
It can also be synthesized by reacting caesium hydroxide with carbon dioxide.
2 CsOH + CO2 → Cs2CO3 + H2O

Safety Profile

Moderately toxic by ingestion. Mutation data reported. When heated to decomposition it emits acrid smoke and fumes. See also CESIUM.

References

[1] Guo L, et al. Applications of Bases in Transition Metal Catalyzed Reactions Zhao Yuan. Chemistry - A European Journal, 2018; 24: 7794-7809.