Sodium acetate


Sodium acetate
Sodium acetate
Identifiers
CAS number 127-09-3 YesY, 6131-90-4 (trihydrate)
PubChem 517045
ChemSpider 29105 YesY
UNII NVG71ZZ7P0 YesY
ChEBI CHEBI:32954 YesY
ChEMBL CHEMBL1354 YesY
RTECS number AJ4300010 (anhydrous)
AJ4580000
Jmol-3D images Image 1
Properties
Molecular formula C2H3NaO2
Molar mass 82.03 g mol−1
Appearance White deliquescent powder
odorless
Density 1.528 g/cm3
1.45 g/cm3 (trihydrate)
Melting point

324 °C (anhydrous)
58 °C (trihydrate)

Boiling point

881.4 °C (anhydrous)
122 °C (trihydrate)(decomposes)

Solubility in water 36.2 g/100 ml (0°C)
46.4 g/100 mL (20°C)
139 g/100 mL (60°C)
170.15 g/100 mL (100°C)
Solubility soluble in ethanol (5.3 g/100 mL (trihydrate)
Basicity (pKb) 9.25
Refractive index (nD) 1.464
Structure
Crystal structure monoclinic
Hazards
MSDS External MSDS
Main hazards Irritant
NFPA 704
NFPA 704.svg
1
1
0
Flash point 250 °C
Autoignition
temperature
607 °C
Related compounds
Other anions Sodium formate
Sodium propionate
Other cations Potassium acetate
Calcium acetate
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sodium acetate, CH3COONa, also abbreviated NaOAc,[1] also sodium ethanoate, is the sodium salt of acetic acid. This colourless salt has a wide range of uses.

Contents

Applications

Industrial

Sodium acetate is used in the textile industry to neutralize sulfuric acid waste streams, and as a photoresist while using aniline dyes. It is also a pickling agent in chrome tanning, and it helps to retard vulcanization of chloroprene in synthetic rubber production.

Concrete longevity

Sodium acetate is used to reduce the damage water can potentially do to concrete by acting as a Concrete sealant, while also being environmentally benign and cheaper than the epoxy alternative that is usually employed for sealing concrete against water permeation [2].

Food

Sodium acetate may be added to foods as a seasoning. It may be used in the form of sodium diacetate — a 1:1 complex of sodium acetate and acetic acid,[3] given the E-number E262. A frequent use of this form is in salt and vinegar chips in the United States. Many US brands, including national manufacturer Frito-Lay, sell "salt and vinegar flavoured" chips that use this chemical, with lactose and smaller percentages of other chemicals, in lieu of a real salt and vinegar preparation.[4]

Buffer solution

As the conjugate base of a weak acid, a solution of sodium acetate and acetic acid can act as a buffer to keep a relatively constant pH. This is useful especially in biochemical applications where reactions are pH dependent.

Heating pad

Sodium acetate is also used in consumer heating pads or hand warmers and is also used in hot ice. Sodium acetate trihydrate crystals melt at 54°C,[5] dissolving in their water of crystallization. When they are heated to around 100°C, and subsequently allowed to cool, the aqueous solution becomes supersaturated. This solution is capable of cooling to room temperature without forming crystals. By clicking on a metal disc in the heating pad, a nucleation centre is formed which causes the solution to crystallize into solid sodium acetate trihydrate again. The bond-forming process of crystallization is exothermic.[6][7][8] The latent heat of fusion is about 264–289 kJ/kg.[9] Unlike some other types of heat packs that depend on irreversible chemical reactions, sodium acetate heat packs can be easily recharged by boiling until all crystals are dissolved; they can be reused indefinitely.[citation needed]

An inexpensive hand warmer containing a supersaturated solution of sodium acetate which releases heat on crystallization

Preparation

a crystal of sodium acetate trihydrate (length 1.7 centimetre)

For laboratory use, sodium acetate is very inexpensive, and is usually purchased instead of being synthesized. It is sometimes produced in a laboratory experiment by the reaction of acetic acid (also called ethanoic acid) with sodium carbonate, sodium bicarbonate, or sodium hydroxide. These reactions produce aqueous sodium acetate and water. Carbon dioxide is produced in the reaction with sodium carbonate and bicarbonate, and it leaves the reaction vessel as a gas (unless the reaction vessel is pressurized). This is the well-known "volcano" reaction between baking soda and vinegar.

CH3COOH + NaHCO3 → CH3COONa + H2O + CO2

Industrially, sodium acetate is prepared from glacial acetic acid and sodium hydroxide.

CH3COOH + NaOH → CH3COONa + H2O

Reactions

Sodium acetate can be used to form an ester with an alkyl halide such as bromoethane:

CH3COONa + BrCH2CH3CH3COOCH2CH3 + NaBr

Caesium salts catalyze this reaction.

References

External links


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Look at other dictionaries:

  • sodium acetate — n the hygroscopic crystalline sodium salt C2H3NaO2 of acetic acid used chiefly in organic synthesis and photography and as a mordant or as an analytical reagent * * * [USP] the trihydrate sodium salt of acetic acid, used as a source of sodium… …   Medical dictionary

  • sodium acetate — noun : either of two sodium salts of acetic acid: a. : the hygroscopic crystalline normal salt CH3COONa used chiefly in organic synthesis and photography and as a mordant or as an analytical reagent b. : the acid salt CH3COONa.CH3COOH used… …   Useful english dictionary

  • sodium acetate C 11 — [USP] sodium acetate in which a portion of the molecules have been labeled with carbon 11, used as a tracer in positron emission tomography in the study of cardiac metabolism; administered intravenously …   Medical dictionary

  • sodium acetate — noun The sodium salt of acetic acid …   Wiktionary

  • sodium acetate —    Colorless, odorless crystals, used in dye and color intermediate; soaps, photography, laboratory reagent, and dehydrating agent …   Forensic science glossary

  • Acetate de sodium — Acétate de sodium Acétate de sodium Général Nom IUPAC Éthanoate de sodium Synonym …   Wikipédia en Français

  • Acétate De Sodium — Général Nom IUPAC Éthanoate de sodium Synonym …   Wikipédia en Français

  • Acétate de sodium trihydraté — Acétate de sodium Acétate de sodium Général Nom IUPAC Éthanoate de sodium Synonym …   Wikipédia en Français

  • Acétate de sodium — Général Nom IUPAC Éthanoate de sodium Synonymes …   Wikipédia en Français

  • Acetate — Acétate En chimie, un acétate (le mot vient du latin acetum, le vinaigre) est un sel ou un ester de l acide acétique. La formule de l ion acétate est CH3COO. Le terme acétate peut aussi faire référence à l’acétate de cellulose, en particulier les …   Wikipédia en Français


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