Silver acetate

Silver acetate
Other names Acetic acid, silver (1+) salt Silver ethanoate
Identifiers
CAS number	563-63-3 Y
PubChem	11246
ChemSpider	10772 Y
UNII	19PPS85F9H Y
EC number	209-254-9
RTECS number	AJ4100000
Jmol-3D images	{{#if:CC(=O)[O-].[Ag+]|Image 1
SMILES CC(=O)[O-].[Ag+]
InChI InChI=1S/C2H4O2.Ag/c1-2(3)4;/h1H3,(H,3,4);/q;+1/p-1 Y Key: CQLFBEKRDQMJLZ-UHFFFAOYSA-M Y InChI=1/C2H4O2.Ag/c1-2(3)4;/h1H3,(H,3,4);/q;+1/p-1 Key: CQLFBEKRDQMJLZ-REWHXWOFAJ
Properties
Molecular formula	AgC2H3O2
Molar mass	166.912 g/mol
Appearance	white to slightly grayish powder slightly acidic odor
Density	3.26 g/cm3, solid
Boiling point	decomposes at 220 °C
Solubility in water	1.02 g/100 mL(20 °C)
Hazards
EU classification	not listed
NFPA 704	0 1 0
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Silver acetate is an organic compound with the empirical formula CH₃COOAg (or AgC₂H₃O₂). It is a photosensitive, white crystalline solid. It is a useful reagent in the laboratory as a water soluble source of silver lacking an oxidizing anion. It has been used in some antismoking drugs.

Synthesis and structure

The silver acetate salt can be synthesized by the reaction of acetic acid and silver carbonate at 45–60 °C. After allowing cooling to room temperature, the solid product precipitates.^[1]

2 CH₃CO₂H + Ag₂CO₃ → 2 AgO₂CCH₃ + H₂O + CO₂

It can also be precipitated from concentrated aqueous solutions of silver nitrate by treatment with a solution of sodium acetate.

The structure of silver acetate consists of 8-membered Ag₂O₄C₂ rings formed by a pair of acetate ligands bridging a pair of silver centres.^[2]

Reactions

Carbonylation

Silver acetate, when combined with carbon monoxide (CO), can induce the carbonylation of primary and secondary amines. Other silver salts can be used but the acetate gives the best yield.

2 R₂NH + 2 AgOAc + CO → [R₂N]₂CO + 2 HOAc + 2 Ag

Hydrogenation

Silver acetate in a solution of pyridine absorbs hydrogen and is reduced to metallic silver.^[3]

Direct ortho-arylation

Silver acetate is a useful reagent for direct ortho-arylation (to install two adjacent substituents on an aromatic ring) for of benzylamines and N-methylbenzylamines. The reaction is palladium-catalized and requires a slight excess of silver acetate.^[4] This reaction is shorter than previous ortho-arylation methods.

Uses

In the health field, silver acetate-containing products have been used in gum, spray, and lozenges to deter smokers from smoking. The silver in these products, when mixed with smoke, creates an unpleasant metallic taste in the smoker's mouth, thus deterring them from smoking. Lozenges containing 2.5 mg of silver acetate showed "modest efficacy" on 500 adult smokers tested over a three-month period. However, over a period of 12 months, prevention failed. In 1974, silver acetate was first introduced in Europe as an over-the-counter smoking-deterrent lozenge (Repaton) and then three years later as a chewing gum (Tabmint).^[5]

Safety

The LD₅₀ of silver acetate in mice is 36.7 mg/kg. Low doses of silver acetate in mice produced hyper-excitability, ataxia, central nervous system depression, labored breathing, and even death.^[6] The U.S. FDA recommends that silver acetate intake be limited to 756 mg over a short period of time; excessive intake may cause argyria.^[5][7]

References

Further reading

• F. H. MacDougall, and S. Peterson (1947). "Equilibria in Silver Acetate Solutions". The Journal of Physical Chemistry 51 (6): 1346–1361. doi:10.1021/j150456a009.