Sodium acetate or Sodium Etanoate . is the sodium salt of Acetic Acid with the molecular formula NaC 2 H 3 O 2 . It is produced in industrial quantities for a wide range of uses.
Summary
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- 1 Physical properties
- 2 Stability and reactivity
- 1 Conditions to avoid
- 3 Synthesis
- 4 Applications of sodium acetate
- 5 Toxicological information
- 6 Sources
Physical properties
- Appearance and Color: White crystalline powder.
- Smell: Odorless.
- Solubility in water: Soluble in: Water 47 g / 100 ml
- Melting point: 324ºC
- Molecular Weight: 82.04
- Molar mass: 82.0343 g / mol
- Melting point: 324 ° C
- Boiling point: 881.4 ° C
- Density: 1.53 g / cm³
- IUPAC Denomination: Sodium Acetate
Stability and reactivity
Dust exposure is possible if it is mixed with air in a powdery or granular form. The substance decomposes when heated intensively above 120ºC or in contact with strong acids producing acetic acid. The solution in water is moderately basic.
Conditions to avoid
- Sources of heat and ignition.
- Materials to avoid: Strong acids.
- Decomposition products: Acetic acid.
- Polymerization : Not applicable.
A hyper-saturated solution of sodium acetate in water (dissolving sodium acetate in hot water and then cooling the solution) crystallizes quickly and is what is commonly known as Hot Ice. Sodium acetate is not sold in pharmacies: it must be synthesized.
Synthesis
Sodium acetate is very inexpensive, and is commonly purchased from chemical distributors rather than being synthesized in the laboratory. It is sometimes experimentally produced in the laboratory by the reaction of acetic acid with sodium carbonate, sodium bicarbonate, or sodium hydroxide, to name a few bases that contain sodium.
CH 3 –COOH + Na [HCO 3 ] → CH 3 –COO– + Na + + H 2 O + CO 2
This is a reaction known as “bubbling” between the baking soda and the vinegar . 84 grams of sodium bicarbonate react with 750 g of vinegar with 8% concentration of acetic acid to make 82 g of sodium acetate in solution. By the subsequent evaporation of the water , a more or less pure solution of Sodium Acetate or its crystals can be obtained and also: CH 3 -COOH + Na (OH).
To get industrial quantities. 100 g of Sodium Hydroxide (NaOH) react with 150 g of pure acetic acid (1875g of 8% vinegar), to give 45 g of water and 205 g of Sodium Acetate.
Sodium Acetate Applications
Sodium acetate is used in the textile industry to neutralize residual currents of sulfuric acid , and as a photoresist when using aniline dyes . It is also used as a pickling agent in chrome tanning. Helps retard vulcanization of chloroprene in synthetic rubber production .
It is the chemical compound that gives flavor to potato chips. It is usually added to foods as a preservative; in this case it is named as sodium diacetate and labeled as E 2 6 2 .
As the conjugate base of a weak acid, a solution of sodium acetate and acetic acid can act as a buffer solution to keep the pH relatively constant . This is especially useful in biochemistry , where the reactions depend on the pH.
It is used in self-activating thermal bags (“hot ice”). When crystals of sodium acetate trihydrate (melting point 58 ° C) are heated (crystals should be put in until they can no longer dissolve) around 100 ° C, they melt. If cooled after this process, a supersaturated solution of sodium acetate in water is obtained. This solution is capable of cooling to room temperature, that is, below its melting point, without forming crystals. By pressing on a metal disc inside the bag, a nucleation center is formed causing crystallization of the solution from solid sodium acetate.
