Silver acetate
Encyclopedia
Silver acetate is a photosensitive, white crystalline substance commonly used as a pesticide
. It also produces a repulsive taste (like excrement) when combined with cigarette smoke, so it is used in chewing gum
and lozenges to aid the cessation of smoking
.
, has been isolated from citric acid-forming strains of the fungi Aspergillus niger
. From A. niger grown on glucose media and inorganic salts, acetic acid was collected, treated with sodium hydroxide, and evaporated to a small volume. After neutralization with nitric acid
, the solution was treated with silver nitrate
. A soft precipitate was filtered off, washed free of nitric acid, and dried in a vacuum. This soft precipitate was assumed to be silver acetate.
(CO), can cause the carbonylation
(the formation of a C=O bond) of primary and secondary amines at room temperature. Many silver salts can be used (i.e. AgOAc, AgNO3, AgCl, AgCN), but silver acetate gives the best product yield.
Metallic silver and acetic acid are also formed as byproducts of these reactions.
Quinolone solutions of silver acetate absorb hydrogen rapidly at 100 °C to form metallic silver.
NHMe + (C6H5)I ⇒(C6H5Me)2(C6H3)CH2N(COMe)Me
This reaction presents a much shorter method than previous ortho-arylation methods (i.e. required picolylamide directing group;
only successful for primary amine derivatives).
In the health field, silver acetate-containing products have been used in such products as gum, spray, and lozenges to deter smokers from smoking. The silver in these products, when mixed with smoke, creates a terrible metallic taste in the smoker's mouth, thus deterring them from smoking. Research has shown that lozenges containing 2.5 mg of silver acetate showed "modest efficacy" on 500 adult smokers tested over a three-month period. However, long-term (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).
In nanotechnology, silver acetate has been loaded into the tube lumen
(the cavity within the tube) of halloysites
(a naturally available aluminosilicate clay) under reduced pressure, washing separation, and heating. This tube has been used as a well-dispersed antimicrobial additive in plastic composites.
) of silver acetate in mice is 36.7 mg/kg (low LD50 means very toxic). Low doses of silver acetate in these mice produced hyper-excitability, ataxia
, central nervous system depression, labored breathing, and even death. The FDA recommends that silver acetate intake be limited to 756 mg over a short period of time; excessive intake may cause argyria
.
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
. It also produces a repulsive taste (like excrement) when combined with cigarette smoke, so it is used in chewing gum
Chewing gum
Chewing gum is a type of gum traditionally made of chicle, a natural latex product, or synthetic rubber known as polyisobutylene. For economical and quality reasons, many modern chewing gums use rubber instead of chicle...
and lozenges to aid the cessation of smoking
Smoking cessation
Smoking cessation is the process of discontinuing the practice of inhaling a smoked substance. This article focuses exclusively on cessation of tobacco smoking; however, the methods described may apply to cessation of smoking other substances that can be difficult to stop using due to the...
.
Isolation
Silver acetate, the silver salt form of acetic acidAcetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...
, has been isolated from citric acid-forming strains of the fungi Aspergillus niger
Aspergillus niger
Aspergillus niger is a fungus and one of the most common species of the genus Aspergillus. It causes a disease called black mold on certain fruits and vegetables such as grapes, onions, and peanuts, and is a common contaminant of food...
. From A. niger grown on glucose media and inorganic salts, acetic acid was collected, treated with sodium hydroxide, and evaporated to a small volume. After neutralization with nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
, the solution was treated with silver nitrate
Silver nitrate
Silver nitrate is an inorganic compound with chemical formula . This compound is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides...
. A soft precipitate was filtered off, washed free of nitric acid, and dried in a vacuum. This soft precipitate was assumed to be silver acetate.
Synthesis
The silver acetate salt was synthesized via the reaction of acetic acid and silver carbonate at 45-60 °C. After allowing cooling to room temperature, the product was filtered off.- C2H3O2 + Ag2CO3 ⇒ AgC2H3O2
Solubility
Silver acetate is a moderately soluble crystalline silver source. 100 mL of water can dissolve just over one gram of silver acetate at 20 °C.- AgC2H302(s) ⇐⇒ Ag+(aq) + C2H3O2- (aq)
Formation of a Precipitate
The precipitate is prepared by mixing two salts, one with Ag+ and another with C2H3O2- (i.e. AgNO3 and NaC2H3O2).- Ag (aq) + C2H3O2- (aq) ⇐⇒ AgC2H302 (s)
Carbonylation
Silver acetate, when combined with carbon monoxideCarbon monoxide
Carbon monoxide , also called carbonous oxide, is a colorless, odorless, and tasteless gas that is slightly lighter than air. It is highly toxic to humans and animals in higher quantities, although it is also produced in normal animal metabolism in low quantities, and is thought to have some normal...
(CO), can cause the carbonylation
Carbonylation
Carbonylation refers to reactions that introduce carbon monoxide into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry.-Organic chemistry:...
(the formation of a C=O bond) of primary and secondary amines at room temperature. Many silver salts can be used (i.e. AgOAc, AgNO3, AgCl, AgCN), but silver acetate gives the best product yield.
- Primary Amine: RNH2 + AgOAc + CO ⇒ RNHCONHR
- Secondary Amine: R2NH + AgOAc + CO ⇒ R2N(CO)2NR2
Metallic silver and acetic acid are also formed as byproducts of these reactions.
Hydrogenation
Silver acetate, when in a solution of pyridine, absorbs hydrogen and is reduced to metallic silver.Quinolone solutions of silver acetate absorb hydrogen rapidly at 100 °C to form metallic silver.
Direct ortho-arylation
Silver acetate can be used in a method for direct ortho-arylation (in which the two substituents on an aromatic ring occupy adjacent carbons) of benzylamines and N-methylbenzylamines. The reaction is palladium-catalized and requires a slight excess of silver acetate.NHMe + (C6H5)I ⇒(C6H5Me)2(C6H3)CH2N(COMe)Me
This reaction presents a much shorter method than previous ortho-arylation methods (i.e. required picolylamide directing group;
only successful for primary amine derivatives).
Uses
In industry, silver acetate has been used in the preparation of highly reflective, conductive silvered polymer films. It also could be used to catalyze cycloaddition reactions of isocyanatoacetates.In the health field, silver acetate-containing products have been used in such products as gum, spray, and lozenges to deter smokers from smoking. The silver in these products, when mixed with smoke, creates a terrible metallic taste in the smoker's mouth, thus deterring them from smoking. Research has shown that lozenges containing 2.5 mg of silver acetate showed "modest efficacy" on 500 adult smokers tested over a three-month period. However, long-term (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).
In nanotechnology, silver acetate has been loaded into the tube lumen
Lumen
Lumen can mean:* Lumen , the SI unit of luminous flux* Lumen , the cavity or channel within a tubular structure* Thylakoid lumen, the inner membrane space of the chloroplast* Phenobarbital...
(the cavity within the tube) of halloysites
Halloysite
Halloysite is a 1:1 aluminosilicate clay mineral with the empirical formula Al2Si2O54. Its main constituents are aluminium , silicon , and hydrogen . Halloysite typically forms by hydrothermal alteration of alumino-silicate minerals. It can occur intermixed with dickite, kaolinite, montmorillonite...
(a naturally available aluminosilicate clay) under reduced pressure, washing separation, and heating. This tube has been used as a well-dispersed antimicrobial additive in plastic composites.
Safety
The LD50 (lethal doseLethal dose
A lethal dose is an indication of the lethality of a given substance or type of radiation. Because resistance varies from one individual to another, the 'lethal dose' represents a dose at which a given percentage of subjects will die...
) of silver acetate in mice is 36.7 mg/kg (low LD50 means very toxic). Low doses of silver acetate in these mice produced hyper-excitability, ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...
, central nervous system depression, labored breathing, and even death. The FDA recommends that silver acetate intake be limited to 756 mg over a short period of time; excessive intake may cause argyria
Argyria
Argyria is a condition caused by improper exposure to chemical forms of the element silver, silver dust, or silver compounds. The most dramatic symptom of argyria is that the skin becomes blue or bluish-grey colored. Argyria may be found as generalized argyria or local argyria...
.