Contents

Sodium benzoate

Sodium benzoate

Skeletal formula
Ball-and-stick model of part of the crystal structure
Ball-and-stick model of packing in the crystal structure
Names
Preferred IUPAC name Sodium benzoate
Other names E211 benzoate of soda
Identifiers
CAS Number	532-32-1 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:113455 Y
ChEMBL	ChEMBL1356 Y
ChemSpider	10305 Y
ECHA InfoCard	100.007.760
E number	E211 (preservatives)
PubChem CID	517055
RTECS number	DH6650000
UNII	OJ245FE5EU Y
CompTox Dashboard (EPA)	DTXSID1020140
InChI InChI=1S/C7H6O2.Na/c8-7(9)6-4-2-1-3-5-6;/h1-5H,(H,8,9);/q;+1/p-1 Y Key: WXMKPNITSTVMEF-UHFFFAOYSA-M Y InChI=1/C7H6O2.Na/c8-7(9)6-4-2-1-3-5-6;/h1-5H,(H,8,9);/q;+1/p-1 Key: WXMKPNITSTVMEF-REWHXWOFAY
SMILES [Na+].[O-]C(=O)c1ccccc1
Properties
Chemical formula	C7H5NaO2
Molar mass	144.105 g·mol−1
Appearance	white or colourless crystalline powder
Odor	odorless
Density	1.497 g/cm3
Melting point	410 °C (770 °F; 683 K)
Solubility in water	62.65 g/100 mL (0 °C) 62.84 g/100 mL (15 °C) 62.87 g/100 mL (30 °C) 74.2 g/100 mL (100 °C)[1]
Solubility	soluble in liquid ammonia, pyridine[1]
Solubilityinmethanol	8.22 g/100 g (15 °C) 7.55 g/100 g (66.2 °C)[1]
Solubilityinethanol	2.3 g/100 g (25 °C) 8.3 g/100 g (78 °C)[1]
Solubilityin1,4-Dioxane	0.818 mg/kg (25 °C)[1]
Pharmacology
ATC code	A16AX11 (WHO)
Hazards
GHS labelling:
Pictograms	[2]
Signal word	Warning
Hazard statements	H319[2]
Precautionary statements	P305+P351+P338[2]
NFPA 704 (fire diamond)	2 1 0
Flash point	100 °C (212 °F; 373 K)
Autoignition temperature	500 °C (932 °F; 773 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	4100 mg/kg (oral, rat)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Sodium benzoate also known as benzoate of soda is the sodium salt of benzoic acid, widely used as a food preservative (with an E numberofE211) and a pickling agent. It appears as a white crystalline chemical with the formulaC₆H₅COONa.

Production[edit]

Sodium benzoate is commonly produced by the neutralization of sodium hydroxide (NaOH) with benzoic acid (C₆H₅COOH),^[3] which is itself produced commercially by partial oxidationoftoluene with oxygen.

Reactions[edit]

Sodium benzoate can be decarboxylated with strong base and heat, yielding benzene:^[4]

${\displaystyle {\ce {C6H5COONa + NaOH -> C6H6 + Na2CO3}}}$

Natural occurrence[edit]

Many foods are natural sources of benzoic acid, its salts, and its esters.^[5] Fruits and vegetables can be rich sources, particularly berries such as cranberry and bilberry. Other sources include seafood, such as prawns, and dairy products.^{[citation needed]}

Uses[edit]

As a preservative[edit]

Sodium benzoate can act as a food preservative. It is most widely used in acidic foods such as salad dressings (for example acetic acidinvinegar), carbonated drinks (carbonic acid), jams and fruit juices (citric acid), pickles (acetic acid), condiments, and frozen yogurt toppings. It is also used as a preservative in medicines and cosmetics.^[6][7] Under these conditions it is converted into benzoic acid (E210), which is bacteriostatic and fungistatic. Benzoic acid is generally not used directly due to its poor water solubility. Concentration as a food preservative is limited by the FDA in the U.S. to 0.1% by weight.^[8] Sodium benzoate is also allowed as an animal food additive at up to 0.1%, per the Association of American Feed Control Officials.^[9] Sodium benzoate has been replaced by potassium sorbate in the majority of soft drinks in the United Kingdom.^[10]

In the 19th century, sodium benzoate as a food ingredient was investigated by Harvey W. Wiley with his 'Poison Squad' as part of the US Department of Agriculture. This led to the 1906 Pure Food and Drug Act, a key event in the early history of food regulation in the United States.

In pharmaceuticals[edit]

Sodium benzoate is used as a treatment for urea cycle disorders due to its ability to bind amino acids.^[11][12] This leads to excretion of these amino acids and a decrease in ammonia levels. Recent research shows that sodium benzoate may be beneficial as an add-on therapy (1 gram/day) in schizophrenia.^[13][14][15] Total Positive and Negative Syndrome Scale scores dropped by 21% compared to placebo.

Sodium benzoate, along with phenylbutyrate, is used to treat hyperammonemia.^[16][17]

Sodium benzoate, along with caffeine, is used to treat postdural puncture headache, respiratory depression associated with overdosage of narcotics,^[18][19] and with ergotamine to treat vascular headache.^[20]

Other uses[edit]

Sodium benzoate is also used in fireworks as a fuel in whistle mix, a powder that emits a whistling noise when compressed into a tube and ignited.^[21][22]

Mechanism of food preservation[edit]

The mechanism starts with the absorption of benzoic acid into the cell. If the intracellular pH falls to 5 or lower, the anaerobic fermentationofglucose through phosphofructokinase decreases sharply,^[23] which inhibits the growth and survival of microorganisms that cause food spoilage.

Health and safety[edit]

In the United States, sodium benzoate is designated as generally recognized as safe (GRAS) by the Food and Drug Administration.^[24] The International Programme on Chemical Safety found no adverse effects in humans at doses of 647–825 mg/kg of body weight per day.^[25][26]

Cats have a significantly lower tolerance against benzoic acid and its salts than rats and mice.^[27]

The human body rapidly clears sodium benzoate by combining it with glycine to form hippuric acid which is then excreted.^[26] The metabolic pathway for this begins with the conversion of benzoate by butyrate-CoA ligase into an intermediate product, benzoyl-CoA,^[28] which is then metabolized by glycine N-acyltransferase into hippuric acid.^[29]

Association with benzene in soft drinks & pepper sauces[edit]

In combination with ascorbic acid (vitamin C, E300), sodium benzoate and potassium benzoate may form benzene. In 2006, the Food and Drug Administration tested 100 beverages available in the United States that contained both ascorbic acid and benzoate. Four had benzene levels that were above the 5 ppb Maximum Contaminant Level set by the Environmental Protection Agency for drinking water.^[30] Most of the beverages that tested above the limit have been reformulated and subsequently tested below the safety limit.^[30] Heat, light and shelf life can increase the rate at which benzene is formed. Hot peppers naturally contain vitamin C ("nearly as much as in one orange"^[31]) so the observation about beverages applies to pepper sauces containing sodium benzoate, like Texas Pete.

ADHD and hyperactivity[edit]

Research published, including in 2007 for the UK's Food Standards Agency (FSA) suggests that certain artificial colors, when paired with sodium benzoate, may be linked to hyperactive behavior and other ADHD symptoms. The results were inconsistent regarding sodium benzoate, so the FSA recommended further study.^[32][33][34] The Food Standards Agency concluded that the observed increases in hyperactive behavior, if real, were more likely to be linked to the artificial colors than to sodium benzoate.^[34] The report's author, Jim Stevenson from Southampton University, said: "The results suggest that consumption of certain mixtures of artificial food colours and sodium benzoate preservative are associated with increases in hyperactive behaviour in children. . . . Many other influences are at work but this at least is one a child can avoid."^[34]

Compendial status[edit]

• British Pharmacopoeia^[35][36][37]
• European Pharmacopoeia^[35]
• Food Chemicals Codex^[35]
• Japanese Pharmacopoeia^[38]
• United States Pharmacopeia^[39]

See also[edit]

• Acceptable daily intake
• List of investigational antipsychotics
• Potassium benzoate

References[edit]

External links[edit]

Wikimedia Commons has media related to Sodium benzoate.

• International Programme on Chemical Safety - Benzoic Acid and Sodium Benzoate report
• Kubota K, Ishizaki T (1991). "Dose-dependent pharmacokinetics of benzoic acid following oral administration of sodium benzoate to humans". Eur. J. Clin. Pharmacol. 41 (4): 363–8. doi:10.1007/BF00314969. PMID 1804654. S2CID 8196430. Although the maximum rate of biotransformation of benzoic acid to hippuric acid varied between 17.2 and 28.8 mg.kg-1.h-1 among the six individuals, the mean value (23.0 mg.kg-1.h-1) was fairly close to that provided by daily maximum dose (0.5 g.kg-1.day-1) recommended in the treatment of hyperammonaemia in patients with inborn errors of ureagenesis
• Safety data for sodium benzoate Archived 11 December 2011 at the Wayback Machine

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