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
Anhydrous salt is a colorless crystalline solid; density 1.528 g/cm3; melts at 324°C; very soluble in water; moderately soluble in ethanol. The colorless crystalline trihydrate has a density 1.45 g/cm3; decomposes at 58°C; is very soluble in water; pH of 0.1M aqueous solution is 8.9; moderately soluble in ethanol, 5.3 g/100mL.
Sodium acetate (CH3COONa) is the sodium salt of acetic acid. It appears as a colorless deliquescent salt with a wide range of applications. In industry, it can be used in textile industry to neutralize sulfuric acid waste streams and as a photoresist upon using aniline dyes. In concrete industry, it can be used as a concrete sealant to mitigate the water damage. In food, it can be used as a seasoning. It can also be used as a buffer solution in lab. In addition, it is also used in heating pads, hand warmers and hot ice. For laboratory use, it can be produced by the reaction between acetate with the sodium carbonate, sodium bicarbonate and sodium hydroxide. In industry, it is prepared from the glacial acetic acid and sodium hydroxide.
Used as buffers.
Acidity regulation (buffering)
Sodium acetate mixed with acetic acid forms a pH buffer, which can be used to stabilise the pH of foods in the pH-range from 3 to 6. The table below gives indicative values of the composition needed to give a certain pH. The mixtures below can be diluted at least 10 times with minimum effect on pH, however, the stability decreases.
Sodium acetate is a mordant in dyeing. 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.
Sodium acetate can be used to preserve processed meats and it is often used in combination with other acid based preservatives like lactates and propionates. The typical inclusion level is 0.2 to 0.5%. Sodium acetate is also used in salad dressings and ready-to-eat meals.
Commonly used laboratory reagent
When sodium acetate reacts with strong acids, irritating, noxious vapors of acetic acid are usually produced. Sodium acetate is sufficiently basic to catalyze the violent polymerization of diketene, perhaps as well as other reactive dimers that are susceptible to polymerization in the presence of a mild base.
Crystallise it from acetic acid and keep it under vacuum for 10hours at 120o. Alternatively, it is crystallised from aqueous EtOH, as the trihydrate. This material can be converted to anhydrous salt by heating slowly in a porcelain, nickel or iron dish, so that the salt liquefies. Steam is evolved and the mass again solidifies. Heating is now increased so that the salt melts again. (NB: if it is heated too strongly, the salt can char; avoid this.) After several minutes, the salt is allowed to solidify and is cooled to a convenient temperature (in a desiccator) before being powdered and bottled. The water content should now be less than 0.02%. [Beilstein 2 II 113, 2 III 184, 2 IV 109.]