Silver acetate

Silver acetate
Names
	Other names Acetic acid, silver (1+) salt; Silver ethanoate
Identifiers
CAS Number	563-63-3 ;
3D model (JSmol)	Interactive image;
ChemSpider	10772 ;
ECHA InfoCard	100.008.414
EC Number	209-254-9;
PubChem CID	11246;
RTECS number	AJ4100000;
UNII	19PPS85F9H ;
CompTox Dashboard (EPA)	DTXSID8032041 ;
	InChI InChI=1S/C2H4O2.Ag/c1-2(3)4;/h1H3,(H,3,4);/q;+1/p-1 Key: CQLFBEKRDQMJLZ-UHFFFAOYSA-M ; InChI=1/C2H4O2.Ag/c1-2(3)4;/h1H3,(H,3,4);/q;+1/p-1 Key: CQLFBEKRDQMJLZ-REWHXWOFAJ;
	SMILES CC(=O)[O-].[Ag+];
Properties
Chemical 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
NFPA 704 (fire diamond)	1 0 0
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Silver acetate is an inorganic compound with the empirical formula CH₃CO₂Ag (or AgC₂H₃O₂). It is a photosensitive, white crystalline solid. It is a useful reagent in the laboratory as a source of silver ions lacking an oxidizing anion. It has been used in some antismoking drugs.

Synthesis and structure

Silver acetate 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

A solution of silver acetate in pyridine absorbs hydrogen, producing metallic silver:^[3]

2 CH₃CO₂Ag + H₂ → 2 Ag + 2 CH₃CO₂H

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.

Oxidative dehalogenation

Silver acetate can be used to convert certain organohalogen compounds into alcohols. It may be used, in spite of its high cost, in instances where a mild and selective reagent is desired.

Woodward cis-hydroxylation

Silver acetate in combination with iodine forms the basis of the Woodward cis-hydroxylation. This reaction selectively converts an alkenes into a cis-diols.^[5]

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).^[6]

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.^[7] 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.^[6]^[8]

References

^ Logvinenko, V.; Polunina, O.; Mikhailov, Yu; Mikhailov, K.; Bokhonov, B. (2007). "Study of Thermal Decomposition of Silver Acetate". Journal of Thermal Analysis and Calorimetry. 90 (3): 813–816. doi:10.1007/s10973-006-7883-9.
^ Leif P. Olson, David R. Whitcomb, Manju Rajeswaran, Thomas N. Blanton, Barbara J. Stwertka "The Simple Yet Elusive Crystal Structure of Silver Acetate and the Role of the Ag−Ag Bond in the Formation of Silver Nanoparticles during the Thermally Induced Reduction of Silver Carboxylates" Chem. Mater., 2006, volume 18, pp 1667–1674. doi:10.1021/cm052657v
^ Wright, Leon (1955). "Homogeneous Catalytic Hydrogenation III. Activation of Hydrogen by Cuprous and Silver Acetates in Pyridine and Dodecylamine". Journal of Physical Chemistry. 59: 1060–1064. doi:10.1021/j150532a016. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Lazareva, Anna; Daugulis (2006). "Olafs". Direct Palladium-Catalyzed Ortho-Arylation of Benzylamines. 8: 5211–5213. doi:10.1021/o1061919b.
^ Woodward, R. B.; Brutcher, F. V. (January 1958). "cis-Hydroxylation of a Synthetic Steroid Intermediate with Iodine, Silver Acetate and Wet Acetic Acid". Journal of the American Chemical Society. 80 (1): 209–211. doi:10.1021/ja01534a053.
^ ^a ^b Hymowitz, Norman; Eckholdt, Haftan (1996). "Effects of a 2.5-mg Silver Acetate Lozenge on Initial and Long-Term Smoking Cessation". Journal of Preventitive Medicine. 25 (5): 537–546. doi:10.1006/pmed.1996.0087. PMID 8888321.
^ Horner, Heidi C.; Roebuck, B.D.; Smith, Roger P.; English, Jackson P. (1977). "Acute toxicity of some silver salts of sulfonamides in mice and the efficacy of penicillamine in silver poisoning". Drug and Chemical Toxicology. 6: 267–277.
^ E. J. Jensen, E. Schmidt, B. Pedersen, R. Dahl (1991). "Effect on smoking cessation of silver acetate, nicotine and ordinary chewing gum, Influence of smoking history". Psychopharmacology. 104 (4): 470–474. doi:10.1007/BF02245651. PMID 1780416.{{cite journal}}: CS1 maint: multiple names: authors list (link)