Sodium acetate trihydrate

Chemical Properties

Sodium acetate trihydrate is the trihydrate sodium salt oaf acetic acid. It is a colorless, odorless crystals that can be weathered in the air. Soluble in water and ether, pH of 0.1M aqueous solution is 8.9. moderately soluble in ethanol, 5.3 g/100mL. Anhydrous Sodium acetate occurs as colorless, transparent crystals or a granular crystalline powder with a slight acetic acid odor.

Uses

Sodium acetate trihydrate is used in various applications. It is used as a buffer of a pH range in between to 4.0 to 6.0. It is also used in the purification and precipitation of nucleic acids and in protein crystallization. It is used as a mordant dyeing, as a pickling agent in chrome tanning, as a neutralizer in waste streams containing sulfuric acid, in the textile industry and as a photoresist while using aniline dyes. It plays an important role to retard vulcanization of chloroprene in synthetic rubber production. It is a precursor to prepare ester from alkyl halide. Other applications are in photography, as an additive to food, in purification of glucose, in preservation of meat, in tanning, and as a dehydrating agent. In analytical chemistry it is used to prepare buffer solution.

Definition

ChEBI: Sodium acetate trihydrate is a hydrate. It contains a sodium acetate.

Preparation

Sodium acetate is prepared by reacting sodium hydroxide or sodium carbonate with acetic acid in aqueous solution. The solution is evaporated to obtain hydrated crystals of sodium acetate.
NaOH + CH3COOH → CH3COONa + H2O
Na2CO3 + CH3COOH → 2CH3COONa + CO2 + H2O

General Description

Sodium acetate trihydrate can be obtained from the crystallization of sodium acetate in water. On heating at 75°C, it melts, while on heating above 120°C it loses water of crystallization and gets converted into anhydrous form. The hyperfine proton and ¹³C splittings have been evaluated by recording ESR spectra of its irradiated single crystals. ESR studies suggested the existence of trapped methyl radicals. Its crystals are monoclinic and its crystal structure has been investigated by photographic methods. Unit cell parameters were evaluated.

Pharmaceutical Applications

Sodium acetate is used as part of a buffer system when combined with acetic acid in various intramuscular, intravenous, topical, ophthalmic, nasal, oral, otic, and subcutaneous formulations. It may be used to reduce the bitterness of oral pharmaceuticals. It can be used to enhance the antimicrobial properties of formulations; it has been shown to inhibit the growth of S. aureus and E. coli, but not C. albicans in protein hydrolysate solutions. It is widely used in the food industry as a preservative. Sodium acetate has also been used therapeutically for the treatment of metabolic acidosis in premature infants, and in hemodialysis solutions.

Biochem/physiol Actions

Sodium acetate trihydrate (SAT) is a phase change material (PCM) that can be easily combined with the preparation of domestic hot water, space heating, solar heating, and radiant floor heating systems. The hydrated salt of SAT possesses high latent heat density and thus can be used for low-temperature heat storage.

Safety

Sodium acetate is widely used in cosmetics, foods, and pharmaceutical formulations, and is generally regarded as a nontoxic and nonirritant material.
A short-term feeding study in chickens with a diet supplemented with 5.44% sodium acetate showed reduced growth rates that were attributed to the sodium content.(9) Sodium acetate is poisonous if injected intravenously, is moderately toxic by ingestion, and is an irritant to the skin and eyes.
LD50 (rat, oral): 3.53 g/kg
LD50 (mouse, IV): 0.38 g/kg
LD50 (mouse, SC): 8.0 g/kg

storage

Sodium acetate should be stored in airtight containers.

Incompatibilities

Sodium acetate reacts with acidic and basic components. It will react violently with fluorine, potassium nitrate, and diketene.

Regulatory Status

GRAS listed. Accepted as a food additive in Europe. Included in the FDA Inactive Ingredients Database (injections, nasal, otic, ophthalmic, and oral preparations).

References

[1] http://www.europlat.org
[2] http://www.rxlist.com/sodium-acetate-drug.htm
[3] http://cosmetics.specialchem.com
[4] http://cecri.csircentral.net/2710/1/036-96.pdf