Sodium benzoate

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Sodium benzoate
Sodium benzoate.jpg
Sodium benzoate from the store.
IUPAC name
Sodium benzoate
Other names
Benzoate of soda
Molar mass 144.10 g/mol
Appearance White solid
Odor Odorless
Density 1.497 g/cm3
Melting point 410 °C (770 °F; 683 K) (decomposes)
Boiling point Decomposes
62.69 g/100 ml (0 °C)
62.78 g/100 ml (15 °C)
62.81 g/100 ml (20 °C)
62.87 g/100 ml (30 °C)
71.11 g/100 ml (100 °C)
Solubility Soluble in liq. ammonia, pyridine
Solubility in 1,4-Dioxane 0.0000818 g/100 g (25 °C)
Solubility in ethanol 2.3 g/100 g (25 °C)
8.3 g/100 g (78 °C)
Solubility in methanol 8.22 g/100 g (15 °C)
7.55 g/100 g (66.2 °C)
Vapor pressure 2.9·10-12 mmHg (25 °C)
Safety data sheet Sigma-Aldrich
Flash point 100 °C (212 °F; 373 K)
Lethal dose or concentration (LD, LC):
4,100 mg/kg (rat, oral)
Related compounds
Related compounds
Benzoic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Sodium benzoate is an organic chemical compound, used as a food preservative.



Sodium benzoate will react with sodium hydroxide to produce benzene:

C6H5COONa + NaOH → C6H6 + Na2CO3

Small amounts of biphenyl and benzophenone will also be produced as side products.

Ascorbic acid will also reduce the salt to benzene under certain conditions.


Sodium benzoate is a white hygroscopic compound, with a characteristic smell. It has a solubility in water of 62.7 g/100 ml at standard conditions. Sodium benzoate is also soluble in liquid ammonia and pyridine. It is poorly soluble in most alcohols, like methanol and ethanol.


Sodium benzoate is available as a food preservative, sold in sealed bags.


Sodium benzoate can be prepared by reacting benzoic acid and sodium hydroxide, bicarbonate or carbonate.


  • Benzene synthesis
  • Make benzoic acid
  • Make benzoic acid esters
  • Whistle mix
  • Food preservative



Sodium benzoate has low toxicity to humans, and recent studies have shown to have some beneficial effects, in preventing Alzheimer and Parkinson's, though the results aren't conclusive so far. Cats however, have a significantly lower tolerance against benzoic acid and its salts, than rats and mice.

If consumed with ascorbic acid, it may yield benzene, which is carcinogen, phenomenon observed in drinks containing sodium benzoate as preservative. However the levels of benzene obtained are extremely small, and studies have shown that the concentration of benzene is well below the safety limit.


Sodium benzoate should be stored in closed bottles, as it's slightly hygroscopic, though keeping it in a dry chamber is sufficient.


Sodium benzoate has low toxicity and doesn't require special disposal. Discard it as you wish.


Relevant Sciencemadness threads