Chemical Properties
Colourless crystals or white powder
Application
Cesium carbonate is widely utilized as a precursor for other cesium compounds. It acts as a base in sensitive organic reactions. It can be used as a base in C-C and C-N cross-coupling reactions such as Suzuki?Miyaura, Heck, and Buchwald-Hartwig amination reactions. It finds use in solar cells as it increases the power conversion efficiency of cells through the transfer of electrons. It is also used in the production of special optical glasses, petroleum catalytic additives, special ceramics and in the sulfuric acid industry. It 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. Promotes the efficient O-alkylation of alcohols to form mixed alkyl carbonates.
Reactions
Many of the properties of cesium carbonate are due to the softness of the cesium cation. This softness makes cesium carbonate rather soluble in organic solvents such as alcohols, DMF and Et2O. This has rendered cesium carbonate useful in palladium chemistry, which is often carried out in non-aqueous media where insolubility of inorganic bases can limit reactivity. Cs2CO3 has, for example, been used with good results in Heck, Suzuki and Sonogashira reactions. Cesium carbonate has also received much attention for its use in O-alkylations, particularly of phenols.It has been postulated that O-alkylations of phenols using Cs2CO3 in non-aqueous solvents occurs via the ‘naked’ phenolate anion, which behaves as a strong nucleophile. Therefore, this methodology can even be applied to secondary halides, minimizing the usual unwanted side reactions such as elimination and decomposition.
General Description
Cesium carbonate is a powerful inorganic base widely used in organic synthesis. It is a potential chemoselective catalyst for the reduction of aldehydes and ketones to alcohols. It is employed as base for the Heck coupling reaction of 4-trifluoromethyl-1-chlorobenzene and aryl chlorides.
Hazard
Cesium carbonate is a danger compound.
H315: Causes skin irritation
H318: Causes serious eye damage
H335: May cause respiratory irritation
H361: Suspected of damaging fertility or the unborn child
H373: May cause damage to organs through prolonged or repeated exposure
Flammability and Explosibility
Nonflammable
Purification Methods
Crystallise it from ethanol (10mL/g) by partial evaporation. [D.nges in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 988 1963.]
References
[1] Guo L, et al. Applications of Bases in Transition Metal Catalyzed Reactions
Zhao Yuan. Chemistry - A European Journal, 2018; 24: 7794-7809.
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