Potassium benzoate
From Wikipedia, the free encyclopedia
| Potassium benzoate | |
|---|---|
 |
|
| IUPAC name |
Potassium benzoate
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| Other names | Benzoic acid, potassium salt |
| Identifiers | |
| CAS number | 582-25-2  |
| PubChem | 11399 |
| EC number | 209-481-3 |
| SMILES |
C1=CC=C(C=C1)C(=O)[O-].[K+]
|
| Properties | |
| Molecular formula | C7H5KO2 |
| Molar mass | 160.2117 g/mol |
| Appearance | White solid hygroscopic |
| Odor | odorless |
| Density | 1.5 g/cm3 |
| Melting point |
> 300 °C |
| Solubility in water | soluble |
| Solubility | soluble in ethanol slightly soluble in methanol insoluble in ether |
| (what is this?) (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Potassium benzoate (E212), the potassium salt of benzoic acid, is a food preservative that inhibits the growth of mold, yeast and some bacteria. It works best in low-pH products, below 4.5, where it exists as benzoic acid.
Acidic foods and beverages such as fruit juice (citric acid), sparkling drinks (carbonic acid), soft drinks (phosphoric acid), and pickles (vinegar) may be preserved with potassium benzoate. It is approved for use in most countries including Canada, the U.S., and the EU, where it is designated by the E number E212. In the EU, it is not recommended for consumption by children.[1]
Potassium benzoate is also used as the whistle in many fireworks. [2]
Contents |
[edit] Synthesis
One very common way to make potassium benzoate is by oxidizing toluene.[3]
Another way to synthesize potassium benzoate in the lab setting is by reacting methyl benzoate with potassium thioacetate.[4]
[edit] Spectra
Carbon 13 NMR The carbon NMR shos 5 unique peas. There are four peaks between 130-140 ppm from the carbons in the benzene ring. There is an additional carbon peak around 178 ppm representing the carbon from the carbonyl. [5].
Infrared Spectrum The following are the main peaks in the IR spectrum. 1610: C=O from carbonyl 1580: C=C from benzene ring [6].
[edit] Mechanism of food preservation
The mechanism of food preservation begins with the absorption of benzoic acid into the cell. If the intracellular pH changes to 5 or lower, the anaerobic fermentation of glucose through phosphofructokinase is decreased by 95%.
[edit] Safety and health
In combination with ascorbic acid (vitamin C), sodium and potassium benzoate may form benzene, a known carcinogen. Heat, light and shelf life can affect the rate at which benzene is formed. The Food and Drug Administration was performing tests in 2006, but the Environmental Working Group is calling for the FDA to publicly release all tests and use their authority to force companies to reformulate to avoid the potential benzene forming combination.[7].
Potassium benzoate was recently described by the Food Commission, who campaign for 'safer, healthier food in the UK', as "mildly irritant to the skin, eyes and mucous membranes". [8]
Cats have a significantly lower tolerance to benzoic acid and its salts than rats and mice.[9]
[edit] See also
[edit] References
- ^ Cosmetic Ingredient Review Expert Panel Bindu Nair (2001). "Final Report on the Safety Assessment of Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate". Int J Tox (20 (Suppl. 3)): 23–50.
- ^ Press Release from Defense Technical Information Center; article- Potassium Benzoate for Pyrotechnic Whistling Compositions: Its Synthesis and Characterization as an Anhydrous Salt
- ^ Preparation of potassium benzoate, US patent 3867439
- ^ Tetraderon Letters 47 (4): 565-567. 2006.
- ^ [SciFinder - Carbon13 NMR Spectrum for 582-25-2]
- ^ [SciFinder - Infrared Spectrum for 582-25-2]
- ^ Press Release from the Environmental Working Group
- ^ Published in The Food Magazine issue 77from the Food Commission UK
- ^ Bedford PG, Clarke EG (1972). "Experimental benzoic acid poisoning in the cat". Vet Rec (90): 53–58. PMID 4672555.
