BENZOIC ACID


Benzoic acid is a white crystalline solid. 
Benzoic acid is slightly soluble in water. 
Benzoic acid is used to make other chemicals, as a food preservative, and for other uses.

EC / List no.: 200-618-2
CAS no.: 65-85-0
Mol. formula: C7H6O2

BENZOIC ACID    
Benzenecarboxylic acid
Phenyl carboxylic acid    
CAS #: 65-85-0    
EC Number: 200-618-2


Formula: C7H6O2 / C6H5COOH
Molecular mass: 122.1
Boiling point: 249°C
Melting point: 122°C
See Notes.
Density: 1.3 g/cm³
Solubility in water, g/100ml at 20°C: 0.29
Vapour pressure, Pa at 25°C: 0.1
Relative vapour density (air = 1): 4.2
Relative density of the vapour/air-mixture at 20°C (air = 1): 1
Flash point: 121°C c.c.
Auto-ignition temperature: 570°C
Octanol/water partition coefficient as log Pow: 1.87  


USES
Benzoate plasticizers, 49% 
sodium and potassium benzoates, 26% 
benzoyl chloride, 12% 
alkyd resins, 3% 
n-butyl benzoate, 2% 
miscellaneous, including pharmaceuticals and as a preservative in surface coatings, emulsions, polishes, waxes and liquid detergents, 8%


Use: Preservative, Cosmetics, Feed, Pharmaceutical, Antimicrobial, Antifungal, Antibacterial, Soft Drink, Alcohol Beverage, Beverage Powder, Ice Cream, Candy, Chewing Gum, Icings, Fruit Juice, Puddings, Sauces, Baking Food, Sauage, Food Colors, Milk, Wine, Flavoring Agent, Dyestuff, Toothpaste, Coating, Rubber.

Applications
Benzoic acid is an important precursor for the preparation of many other organic substances viz. benzoyl chloride, benylbenzoate, phenol, sodium benzoate, benzyl alcohol as well as benzoate plasticizers such as glycol-, diethhyleneglycol- and triethyleneglycol esters. Benzoic acid and its salts are used as food preservatives. It is involved in rubber polymerization as an activator and a retardant. It is the main component of benzoin resin and is a constituent of Whitfield’s ointment, which is used for the treatment of fungal skin diseases such as tinea, ringworm and athlete’s foot. It is widely used in cosmetics, dyes, plastics and insect repellents.

Notes
Incompatible with strong oxidizing agents, reducing agents and strong bases.

Benzoic acid (E210) and its salts are also used as food preservatives to prevent the growth of moulds, yeasts and some bacteria
The action of benzoic acid is highly dependant on the pH of the food to which it is being added and it is predominantly used in acidic foods such as fruit juices, sparkling drinks and pickles.


Benzoic acid is a mono-functional, aromatic acid, which is widely used as a building block for the synthesis of alkyd resins. When used as a component of alkyd resins, it improves gloss, hardness and chemical resistance.
Applications/uses
Agriculture intermediates
Cosmetic ingredients - lips
Cosmetic ingredients eyes & face
Personal care ingredients


Benzoic acid is an aromatic alcohol existing naturally in many plants and is a common additive to food, drinks, cosmetics and other products. It acts as preservatives through inhibiting both bacteria and fungi.

Benzoic acid is the simplest of the aromatic carboxylic acids, a family of organic compounds containing the carboxyl (-COOH) group. It occurs in the form of white crystalline needles or thin plates. Many naturally occurring plants contain benzoic acid, including most types of berries and the natural product called gum benzoin, a plant common to the islands of Java, Sumatra, and Borneo. Gum benzoin may contain up to 20 percent benzoic acid. Benzoic acid is also excreted by most animals (except fowl) in the form of a related compound called hippuric acid (C6H5CONHCH2COOH).


Benzoic acid is used as a food preservative. It inhibits the growth of yeast, mold, and other bacteria. Acidic food and fruit juices, sparkling drinks, and pickles are preserved with benzoic acid. It is also used as a preservative in cosmetics.

Benzoic acid is used as an intermediate by manufacturers of alkyd and polyester resins.

Benzoic acid is a compound comprising a benzene ring core carrying a carboxylic acid substituent. 
Benzoic acid has a role as an antimicrobial food preservative, an EC 3.1.1.3 (triacylglycerol lipase) inhibitor, an EC 1.13.11.33 (arachidonate 15-lipoxygenase) inhibitor, a plant metabolite, a human xenobiotic metabolite, an algal metabolite and a drug allergen. 
Benzoic acid is a conjugate acid of a benzoate.

Benzoic Acid is a chemical intermediate for benzoates, alkyd resins and other organic derivatives. It is an excellent vulcanisation retardant in rubber industry. It is also utilised in various varnishes and lacquer paints it enhances the lustre, eases application and is an effective fungicide.

APPLICATIONS
Rubber, Varnishes, Lacquers
INDUSTRIES
Rubber Industry, Paints and Coatings

Benzoic acid is a white (or colorless) solid with the formula C6H5CO2H. 
It is the simplest aromatic carboxylic acid. 
The name is derived from gum benzoin, which was for a long time its only source. 
Benzoic acid occurs naturally in many plants and serves as an intermediate in the biosynthesis of many secondary metabolites. 
Salts of benzoic acid are used as food preservatives. Benzoic acid is an important precursor for the industrial synthesis of many other organic substances. 
The salts and esters of benzoic acid are known as benzoates 


Benzoic acid and its salts (Na or K salts) is a bacteriostatic antiseptic that is only active in an acidic environment (pH 2.5 to 4.5).
In mammals, benzoic acid is primarily metabolized to its glycine conjugate, hippuric acid, which is readily excreted via the renal organic anion transport system. 
Moreover, benzoic acid is also found as a metabolite of benzyl alcohol (for more information on benzyl alcohol see the dedicated questions and answers document).
Benzoic acid is mainly used as preservative at levels from 0.01 to 0.2%.


Benzoic acid is a key raw material in the production of alkyd resins to control viscosity and enhance desirable characteristics in the final alkyd coating film, including gloss, adhesion, hardness, and chemical resistance, particularly resistanceto alkaline substances. 

Benzoic acid is also used as an additive for effective corrosion inhibition.

Benzoic acid is the most basic of aromatic carboxylic acids. This product is a building block used in the manufacture of many end products including alkyd resins. When used in alkyd resin applications, it improves gloss, hardness and chemical resistance. Benzoic acid is also used in other applications including pharmaceuticals, personal care and select industrial applications. Benzoic acid can be used as a preservative given that it increases storage stability and mitigates corrosion when used in emulsion formulations, liquid detergents, paints, polishes and waxes.

General description
Benzoic acid is an organic aromatic monocarboxylic acid. 
Benzoic acid  can be synthesized by the cobalt or manganese catalyzed atmospheric oxidation of toluene. 
Recently, benzoic acid has been prepared from toluene by employing TiO2 nanotubes electrode.
Benzoic acid reacts with hydrogenating reagents to afford hexahydrobenzoic acid. 
The thermal decomposition of the product in the presence of lime or alkali produces benzene and carbon dioxide.

Application
Benzoic acid has been used in the preparation of vials for the HPLC analysis of various polyamines in biological fluids, tissues and isolated/cultured cells.
It may be employed as an intermediate in the synthesis of the following:
• paints
• pigments
• varnish
• wetting agents
• aroma compounds
• benzoyl chloride
• benzotrichloride

Benzoic acid  may also be used to investigate the mechanism of complex addition reaction of hydroxyl radicals with various aromatic compounds.

Benzoic acid is one of the preservatives that widely used in the food industry to protect food from any harmful chemical changes and helps to regulate the growth of microbes better.


Benzoic acid is a commonly used antimicrobial preservative in food and beverages, especially in carbonated beverages, as it presents its strongest antibacterial activity at pH 2.5–4.0. 
Benzoic acid has inhibitory effects on the proliferation of bacteria and yeasts, a major cause of food spoilage. 

Benzoic acid, which is usually used in the form of its sodium salt, sodium benzoate, has long been used as an antimicrobial additive in foods. It is used in carbonated and still beverages, syrups, fruit salads, icings, jams, jellies, preserves, salted margarine, mincemeat, pickles and relishes, pie, pastry fillings, prepared salads, fruit cocktail, soy sauce, and caviar. The use level ranges from 0.05 to 0.1%.

Benzoic acid in the acid form is quite toxic but its sodium salt is much less toxic. The sodium salt is preferred because of the low aqueous solubility of the free acid. In vivo, the salt is converted to acid, which is the more toxic form.

Benzoic acid is an organic acid first used in foods almost 100 years ago. It occurs naturally in prunes, cinnamon, and cloves. 
The free acid form is poorly soluble in water and the sodium salt (sodium benzoate) is often used because of its greater solubility. 
Benzoic acid's antimicrobial activity is primarily against yeasts and molds. As mentioned for other organic acids, antimicrobial activity is greatest at low pH. The effect results from greater permeability of the unionized form into microorganisms. Benzoic acid's most common uses are in carbonated beverages, pickles, sauces, and jelly. Non-food applications for benzoic acid's antibacterial function are found in cosmetics. Benzoic acid itself has low toxicity, but there has been concern because of a potential reaction that converts it to benzene. Although benzene is a toxic and carcinogenic compound, the reaction causing this change has a very low chance of occurring in food. Typically, benzene is rapidly converted to hippuric acid in the body and excreted in the urine. 
Parabens are antimicrobial compounds chemically derived from benzoic acid. Chemically, parabens are esters made by combining benzoic acid and alcohols such as methanol or propanol. Paraben esters have antimicrobial activity against molds and yeasts and are used in beer, soft drinks, and olives. Cosmetics and pharmaceuticals represent the largest use of parabens.


As a kind of organic acidifier, benzoic acid (C7H6O2, BA) is the colorless crystalline solid, which is the simplest aromatic carboxylic acid 

Preferred IUPAC name: Benzoic acid
Systematic IUPAC name: Benzenecarboxylic acid

Other names
Carboxybenzene
E210
Dracylic acid
Phenylmethanoic acid
BzOH

Identifiers
CAS Number: 65-85-0 
EC Number: 200-618-2
E number: E210 (preservatives)

Properties
Chemical formula: C7H6O2
Molar mass: 122.123 g·mol−1
Appearance: Colorless crystalline solid
Odor: Faint, pleasant odor

Density    
1.2659 g/cm3 (15 °C)
1.0749 g/cm3 (130 °C)

Melting point: 122 °C (252 °F; 395 K)
Boiling point: 250 °C (482 °F; 523 K)[7]

Solubility in water    
1.7 g/L (0 °C)
2.7 g/L (18 °C)
3.44 g/L (25 °C)
5.51 g/L (40 °C)
21.45 g/L (75 °C)
56.31 g/L (100 °C)

Solubility: soluble in acetone, benzene, CCl4, CHCl3, alcohol, ethyl ether, hexane, phenyls, liquid ammonia, acetates

Solubility in methanol: 
30 g/100 g (-18 °C)
32.1 g/100 g (-13 °C)
71.5 g/100 g (23 °C)

Solubility in ethanol    
25.4 g/100 g (-18 °C)
47.1 g/100 g (15 °C)
52.4 g/100 g (19.2 °C)
55.9 g/100 g (23 °C)

Solubility in acetone: 54.2 g/100 g (20 °C)
Solubility in olive oil: 4.22 g/100 g (25 °C)
Solubility in 1,4-Dioxane: 55.3 g/100 g (25 °C)
log P: 1.87

Vapor pressure: 
0.16 Pa (25 °C)
0.19 kPa (100 °C)
22.6 kPa (200 °C)

Acidity (pKa)    
4.202 (H2O)
11.02 (DMSO)

Magnetic susceptibility (χ): -70.28·10−6 cm3/mol

Refractive index (nD)    
1.5397 (20 °C)
1.504 (132 °C)

Viscosity: 1.26 mPa (130 °C)

Structure
Crystal structure: Monoclinic
Molecular shape    planar
Dipole moment: 1.72 D in dioxane

Thermochemistry
Heat capacity (C): 146.7 J/mol·K
Std molar entropy (So298): 167.6 J/mol·K
Std enthalpy of formation (ΔfH⦵298): -385.2 kJ/mol
Std enthalpy of combustion (ΔcH⦵298): -3228 kJ/mol

Hazards
Main hazards: Irritant
GHS pictograms    GHS05: CorrosiveGHS07: Harmful
GHS Signal word    Danger
GHS hazard statements: H318, H335
GHS precautionary statements: P261, P280, P305+351+338
NFPA 704 (fire diamond)    
NFPA 704 four-colored diamond
210
Flash point: 121.5 °C (250.7 °F; 394.6 K)
Autoignition temperature: 571 °C (1,060 °F; 844 K)
Lethal dose or concentration (LD, LC): 
LD50 (median dose): 1700 mg/kg (rat, oral)

Related compounds
Related carboxylic acids    
Hydroxybenzoic acids
Aminobenzoic acids,
Nitrobenzoic acids,
Phenylacetic acid


Related compounds    
Benzaldehyde,
Benzyl alcohol,
Benzoyl chloride,
Benzylamine,
Benzamide


Benzoic acid is most commonly found in industrial settings to manufacture a wide variety of products such as perfumes, dyes, topical medications and insect repellents.

Benzoic acid’s salt (sodium benzoate) is commonly used as a pH adjustor and preservative in food, preventing the growth of microbes to keep food safe. It works by changing the internal pH of microorganisms to an acidic state that is incompatible with their growth and survival.

Benzoic acid, a white, crystalline organic compound belonging to the family of carboxylic acids, widely used as a food preservative and in the manufacture of various cosmetics, dyes, plastics, and insect repellents.

First described in the 16th century, benzoic acid exists in many plants; it makes up about 20 percent of gum benzoin, a vegetable resin. It was first prepared synthetically about 1860 from compounds derived from coal tar. It is commercially manufactured by the chemical reaction of toluene (a hydrocarbon obtained from petroleum) with oxygen at temperatures around 200° C (about 400° F) in the presence of cobalt and manganese salts as catalysts. Pure benzoic acid melts at 122° C (252° F) and is very slightly soluble in water.

Among the derivatives of benzoic acid are sodium benzoate, a salt used as a food preservative; benzyl benzoate, an ester used as a miticide; and benzoyl peroxide, used in bleaching flour and in initiating chemical reactions for preparing certain plastics.


Benzoic acid is an alkyl benzoate preservative that occurs in nature in cherry bark, raspberries, tea, anise, and cassia bark. Benefits of benzoic acid in skincare include anti-aging, soothing, and moisturizing properties. In addition, a major derivative of benzoic acid, known as phenolic veratric acid, contains high concentrations of antioxidants to help neutralize free-radicals present in the environment. As a preservative, benzoic acid possesses a wide variety of cosmetic applications, including product stabilizer, fragrance additive, and emollient. 1

For this reason, it can be found diversely throughout products such as sunscreens, lipsticks, and lotions. As a product stabilizer, benzoic acid helps to regulate pH and protect the integrity of ingredients. Topical application of benzoic acid may also play a role in reinforcing skin barrier function, thus promoting the skin’s ability to retain moisture. With its benefits combined, benzoic acid is equipped to improve the quality of both skin and skincare products. 2
Together, these characteristics help to alleviate dry skin and improve the skin’s ability to retain moisture. 


History
Benzoic acid was discovered in the sixteenth century. The dry distillation of gum benzoin was first described by Nostradamus (1556), and then by Alexius Pedemontanus (1560) and Blaise de Vigenère (1596).[10]

Justus von Liebig and Friedrich Wöhler determined the composition of benzoic acid.
These latter also investigated how hippuric acid is related to benzoic acid.

In 1875 Salkowski discovered the antifungal abilities of benzoic acid, which was used for a long time in the preservation of benzoate-containing cloudberry fruits.

Production
Industrial preparations
Benzoic acid is produced commercially by partial oxidation of toluene with oxygen. The process is catalyzed by cobalt or manganese naphthenates. The process uses abundant materials, and proceeds in high yield.[13]

toluene oxidation
The first industrial process involved the reaction of benzotrichloride (trichloromethyl benzene) with calcium hydroxide in water, using iron or iron salts as catalyst. The resulting calcium benzoate is converted to benzoic acid with hydrochloric acid. The product contains significant amounts of chlorinated benzoic acid derivatives. For this reason, benzoic acid for human consumption was obtained by dry distillation of gum benzoin. Food-grade benzoic acid is now produced synthetically.

Laboratory synthesis
Benzoic acid is cheap and readily available, so the laboratory synthesis of benzoic acid is mainly practiced for its pedagogical value. It is a common undergraduate preparation.

Benzoic acid can be purified by recrystallization from water because of its high solubility in hot water and poor solubility in cold water. The avoidance of organic solvents for the recrystallization makes this experiment particularly safe. This process usually gives a yield of around 65%[14]

By hydrolysis
Like other nitriles and amides, benzonitrile and benzamide can be hydrolyzed to benzoic acid or its conjugate base in acid or basic conditions.

From Grignard reagent
Bromobenzene can be converted to benzoic acid by "carboxylation" of the intermediate phenylmagnesium bromide.
This synthesis offers a convenient exercise for students to carry out a Grignard reaction, an important class of carbon–carbon bond forming reaction in organic chemistry.

BENZENE CARBOXYLIC ACID
BENZENE FORMIC ACID
BENZENECARBOXYLIC ACID
BENZENEFORMIC ACID
BENZENEMETHANOIC ACID
BENZENEMETHONIC ACID
BENZOATE
BENZOIC ACID
CARBOXYBENZENE
CARBOXYLBENZENE
DIACYCLIC ACID
DRACYCLIC ACID
DRACYLIC ACID
E 210
HA 1
HA 1 (ACID)
PHENYL CARBOXYLIC ACID
PHENYLCARBOXYLIC ACID
PHENYLFORMIC ACID
RETARDED BA
RETARDER BA
RETARDEX
SALVO LIQUID
SALVO POWDER
SOLVO POWDER
TENN-PLAS
TENNPLAS

Oxidation of benzyl compounds
Benzyl alcohol and benzyl chloride and virtually all benzyl derivatives are readily oxidized to benzoic acid.

Uses
Benzoic acid is mainly consumed in the production of phenol by oxidative decarboxylation at 300−400 °C:

C6H5CO2H + 1/2 O2 → C6H5OH + CO2
The temperature required can be lowered to 200 °C by the addition of catalytic amounts of copper (II) salts. 
The phenol can be converted to cyclohexanol, which is a starting material for nylon synthesis.

Precursor to plasticizers
Benzoate plasticizers, such as the glycol-, diethyleneglycol-, and triethyleneglycol esters, are obtained by transesterification of methyl benzoate with the corresponding diol.
These plasticizers, which are used similarly to those derived from terephthalic acid ester, represent alternatives to phthalates.

Precursor to sodium benzoate and related preservatives
Benzoic acid and its salts are used as a food preservatives, represented by the E numbers E210, E211, E212, and E213. 
Benzoic acid inhibits the growth of mold, yeast[24] and some bacteria. 
It is either added directly or created from reactions with its sodium, potassium, or calcium salt. 
The mechanism starts 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%. 
The efficacy of benzoic acid and benzoate is thus dependent on the pH of the food.
Acidic food and beverage like fruit juice (citric acid), sparkling drinks (carbon dioxide), soft drinks (phosphoric acid), pickles (vinegar) or other acidified food are preserved with benzoic acid and benzoates.

Typical levels of use for benzoic acid as a preservative in food are between 0.05 and 0.1%. 
Foods in which benzoic acid may be used and maximum levels for its application are controlled by local food laws.

Concern has been expressed that benzoic acid and its salts may react with ascorbic acid (vitamin C) in some soft drinks, forming small quantities of carcinogenic benzene.

Medicinal
Benzoic acid is a constituent of Whitfield's ointment which is used for the treatment of fungal skin diseases such as tinea, ringworm, and athlete's foot.
As the principal component of gum benzoin, benzoic acid is also a major ingredient in both tincture of benzoin and Friar's balsam. 
Such products have a long history of use as topical antiseptics and inhalant decongestants.

Benzoic acid was used as an expectorant, analgesic, and antiseptic in the early 20th century.

Niche and laboratory uses
In teaching laboratories, benzoic acid is a common standard for calibrating a bomb calorimeter.

Biology and health effects
Benzoic acid occurs naturally as do its esters in many plant and animal species. 
Appreciable amounts are found in most berries (around 0.05%). Ripe fruits of several Vaccinium species (e.g., cranberry, V. vitis macrocarpon; bilberry, V. myrtillus) contain as much as 0.03–0.13% free benzoic acid. 
Benzoic acid is also formed in apples after infection with the fungus Nectria galligena. 
Among animals, benzoic acid has been identified primarily in omnivorous or phytophageous species, e.g., in viscera and muscles of the rock ptarmigan (Lagopus muta) as well as in gland secretions of male muskoxen (Ovibos moschatus) or Asian bull elephants (Elephas maximus).
Gum benzoin contains up to 20% of benzoic acid and 40% benzoic acid esters.[34]

In terms of its biosynthesis, benzoate is produced in plants from cinnamic acid.
A pathway has been identified from phenol via 4-hydroxybenzoate.

Reactions
Reactions of benzoic acid can occur at either the aromatic ring or at the carboxyl group.

Aromatic ring
benzoic acid aromatic ring reactions
Electrophilic aromatic substitution reaction will take place mainly in 3-position due to the electron-withdrawing carboxylic group; i.e. benzoic acid is meta directing.

Carboxyl group
Reactions typical for carboxylic acids apply also to benzoic acid.

Benzoate esters are the product of the acid catalysed reaction with alcohols.
Benzoic acid amides are usually prepared from benzoyl chloride.
Dehydration to benzoic anhydride is induced with acetic anhydride or phosphorus pentoxide.
Highly reactive acid derivatives such as acid halides are easily obtained by mixing with halogenation agents like phosphorus chlorides or thionyl chloride.
Orthoesters can be obtained by the reaction of alcohols under acidic water free conditions with benzonitrile.
Reduction to benzaldehyde and benzyl alcohol is possible using DIBAL-H, LiAlH4 or sodium borohydride.
Decarboxylation to benzene may be effected by heating in quinoline in the presence of copper salts. Hunsdiecker decarboxylation can be achieved by heating the silver salt.

benzoic acid
65-85-0
Dracylic acid
benzenecarboxylic acid
Carboxybenzene
Benzeneformic acid
phenylformic acid
Benzenemethanoic acid
Phenylcarboxylic acid
Retardex
Benzoesaeure GK
Benzoesaeure GV
Retarder BA
Tenn-Plas
Acide benzoique
Salvo liquid
Solvo powder
Benzoesaeure
Flowers of benzoin
Flowers of benjamin
Benzoic acid, tech.
Unisept BZA
HA 1 (acid)
Kyselina benzoova
Benzoic acid (natural)
Benzoate (VAN)
HA 1
Benzoesaeure [German]
Caswell No. 081
Diacylic acid
Oracylic acid
Acide benzoique [French]
Acido benzoico [Italian]
Benzenemethonic acid
Kyselina benzoova [Czech]
NSC 149
E 210
FEMA No. 2131
CCRIS 1893
Diacylate
HSDB 704
UNII-8SKN0B0MIM
AI3-0310
Salvo, liquid
Solvo, powder
AI3-03710
phenyl formic acid
EPA Pesticide Chemical Code 009101
Benzoic acid Natural
E210
:30746
Aromatic carboxylic acid
MFCD00002398
8SKN0B0MIM
Benzeneformate
Phenylformate
Benzenemethanoate
Phenylcarboxylate
Benzenecarboxylate
DSSTox_CID_143
DSSTox_RID_75396
DSSTox_GSID_20143
Benzoic acid, 99%, extra pure
benzoic-acid
Acido benzoico
Benzoic acid, 99.5%, for analysis
Benzoic acid, 99.6%, ACS reagent
Carboxypolystyrene
Benzoic acid [USAN:JAN]
CAS-65-85-0
NSC7918
Benzoic acid (TN)
EINECS 200-618-2
Benzoic acid [USP:JAN]
phenylcarboxy
Dracylate
benzoic aicd
bezoic acid
Aromatic acid
benzenecarboxylic
Salvo powder
benzoic- acid
Retarder BAX
1gyx
1kqb
benzoic acid group
Benzoic Acid USP
Sodium benzoic acid
Benzoic Acid,(S)
Natural Benzoic Acid
Benzoic acid solution
BENZOICACID-D5
Benzoic acid-[13C7]
WLN: QVR
benzene-2-carboxylic acid
Benzoic Acid-[18O2]
Benzoic acid, ACS reagent
bmse000300
CHEMBL541

Benzoic Acid
Benzoic acid (E210 or INS210), a colorless aromatic carboxylic acid, is naturally present in plant (fruits, nuts, spices and vegetable), fungal and animal tissues, but it can also be produced by microorganisms during food processing and/or be added as a food additive. 
Rich natural sources of benzoic acid are strawberries (up to 29 mg/kg), cayenne pepper and mustard seeds (up to 10 mg/kg), cloves, salvia, thyme and nutmeg (up to 50 mg/kg) and cinnamon (up to 335 mg/kg) (del Olmo et al., 2017). Benzoic acid levels in milk were also found to very sharply increase during fermentation, presumably due to the activity of lactic acid bacteria, Pseudomonas and/or Escherichia coli. Levels of up to 24 mg/L have been reported in fermented cow's milk. 
The benzoic acid levels in raw cow's milk cheese ripened for 6 months can be as high as 250 mg/kg (Del Olmo et al., 2017).
Next to its natural occurrence in food, benzoic acid and its derivatives are also commonly supplemented as antibacterial and –fungal preservatives or flavoring agents (Del Olmo et al., 2017). Benzoic acid has a low taste threshold and low volatility and wide antimicrobial spectrum (Ashurst, 1991). 
Although the undissociated form of benzoic acid is proven to be more effective as antimicrobial agent, the salt, due to its better water solubility, is more often used in food applications.
The maximal antimicrobial activity of benzoic acid has been described between pH 2.5 and 4.5. 
It is clear that benzoic acid and its derivatives are, hence, most often used as preservatives in acid food products. 
However, when using benzoic acid as food additive, care needs to be taken that the food product's taste is not altered in such way that it becomes unacceptable. 
Benzoic acid is known to cause oral prickling, to increase the perception of sweetness, to reduce sourness and saltiness perception and to strongly suppress the perception of bitterness (Otero-Losada, 2003).
Notwithstanding its approval for food use and GRAS status, the toxicology of benzoic acid and its derivatives has always been controversial (Del Olmo et al., 2017). 
Information on maximum allowed limits of benzoic acid and its salt as food additives can be found in the Codex Alimentarius (Food and Agriculture Organization of the United Nations and World Health Organization, 2017).

Benzoic acid and its sodium salt are used as preservatives, which are mainly used in pickled products and beverages. 
The maximum amount used in foods ranges from 0.2 to 2.0 g/kg. 
If benzoic acid is excessively added to the food, it will destroy the VB1 in the food and make the calcium insoluble, which can destroy the absorption of calcium by the human body. 
Furthermore, a long-term intake of benzoic acid will increase the risk of cancer. 
Therefore, it is necessary to ensure low levels of these preservatives in food to meet regulatory standards.


Benzoic acid or its sodium salt, benzoate, was the first chemical preservative permitted in foods in the USA. 
It is still widely used today for a large number of foods. The pK of benzoic acid is rather low (pK 4.20), so its main antimicrobial effect, due to the undissociated acid, will be for high acid foods such as ciders, soft drinks and dressings. It is most suitable for foods with a pH lower than 4.5, but has also found use in margarine, fruit salads, sauerkraut, jams and jellies. 
Benzoate acts essentially as a mould and yeast inhibitor in high acid foods and the poor activity at pH values above 4.0 limits its use against bacteria. 
Benzoic acid naturally occurs in cranberries, prunes, strawberries, apples and yogurts (Chipley, 1993). 
In certain foods, benzoate may impart a disagreeable taste described as ‘peppery’ or burning.
The antimicrobial effect of benzoic acid has been assumed only to be expressed by the undissociated acid interfering with the permeability of the cell membrane and the proton-motive force (Eklund, 1989). However, as for sorbic and propionic acid, benzoic acid has a certain antimicrobial activity in the dissociated form (Chipley, 1993). 
Benzoate also specifically inhibits amino acid uptake and certain enzymes within the cell: alpha-ketoglutarate, succinate dehydrogenase, 6-phosphofructo-2-kinase and lipase.
In a comparative study, Islam (2002) investigated the effect of dipping turkey frankfurters in 25 per cent solutions of propionate, benzoate, diacetate or sorbate on the growth of Listeria monocytogenes. The organic acids were equally effective in reducing L. monocytogenes when the frankfurters were stored at 4°C for 14 days (reduction around 3–4 log cfu/g) but when stored at 13°C, benzoate and diacetate were more effective than propionate and sorbate.
A quite new application method for benzoic acid is active packaging. Weng et al. (1997) treated ionomer films with alkali. 
The resulting release of benzoic acid inhibited Penicillium and Aspergillus in microbial media.

Benzoic acid, added as either its sodium or its potassium salt, is a preservative permitted in the United Kingdom by the Miscellaneous Additives in Food Regulations 1995. 
It is necessary to use preservatives in some soft drinks to ensure the safety of the product by protecting it from spoilage micro-organisms. 
Benzoic acid has been widely tested (see 2.6.6) and accepted as safe by the European Union and United Kingdom authorities. 
Any refusal to purchase products containing this preservative is therefore a matter of a condition of a commercial contract rather than because benzoic acid is in any way not permitted for use in soft drinks. The authorisation and conditions of use of preservatives are governed in the European Union by Directive 95/2/EC of the European Parliament and Council of 20 February 1995 on Food Additives other than Colours and Sweeteners.
There has been much public concern that some food additives cause adverse reactions, although investigations show that it is mostly based on misconception rather than on identifiable adverse reactions.
Preservatives have rarely been shown to cause true allergenic (immunological) reactions. 
Among the food additives reported to cause adverse reactions are benzoic acid and its derivatives (E210–213), which may trigger asthma characterised by breathing difficulties, shortness of breath, wheezing and coughing in sensitive (i.e. asthmatic) individuals. 
Most local authority purchases are for supply to schools and other places where young or vulnerable individuals may consume the products.
The provision of appropriate labelling is accepted by the UK government as an appropriate way of notifying the public of the presence of food additives, thus enabling informed choice to be made by the consumer.
Individual local authorities may have their own specific reasons for not wishing to purchase drinks containing benzoic acid. 
Where benzoic acid is not wanted in products, it can usually be replaced effectively by the use of sorbic acid. Sulphur dioxide is of similar concern because of adverse reaction but it is now not used in ready-to-drink products that are likely to be purchased by local authorities.

Benzoic acid is an intermediary metabolite in this pathway with further metabolism to hippuric acid which is ultimately excreted in the urine where it can be used as a biomarker of acetophenone exposure.

SOFT DRINKS | Chemical Composition
K. Jorge, in Encyclopedia of Food Sciences and Nutrition (Second Edition), 2003
Benzoic Acid
Benzoic acid or benzene-carbonic-acid is a monobasic aromatic acid, moderately strong, white crystalline powder, very soluble in alcohol, ether, and benzene, but poorly soluble in water (0.3 g of benzoic acid in 100 g of water at 20 °C).
Benzoic acid has the advantage that it does not affect the odor or taste of the soft drink, if used in small quantities. 
The preserving quality of benzoic acid is based on its activity to delay the multiplication of several groups of microorganisms, which, however, are not killed by this product. 
The low solubility of benzoic acid in water complicates its application in products containing large amounts of water. 
Therefore, the water-soluble salt sodium benzoate is used.
This product, which is the salt of benzoic acid, has no preserving activity by itself. 
Therefore, after addition of sodium benzoate, the acidity of the soft drink is increased (pH < 3.5), with the result that free undissociated benzoic acid is formed, which has a preserving property. In an alkaline environment, benzoic acid is split into ions and thus loses its preserving activity.
Sodium benzoate is the sodium salt of benzoic acid used as a white crystalline or amorphous (without crystal structure) powder, very soluble in water (66 g of sodium benzoate in 100 g of water at 20 °C) but poorly soluble in alcohol.


Benzoic acid is generally recognized as safe (GRAS) for use as a food preservative in high-acid foods and occurs naturally in some organisms. 
Among foods commonly preserved with the acid are soft drinks, fruit juices, fermented vegetables, and high-sugared foods. The mechanism of antimicrobial action occurs through acidification of cytoplasm and inhibition of critical metabolic enzymes and processes, including macroautophagy. 
Benzoic acid tolerance by certain yeast species and other factors militating against its effectiveness necessitate combination treatments with other synergistic methods. 
Benzoic acid is rapidly metabolized and excreted as hippuric acid.

Benzoic acid and its derivatives are naturally found in different plants, fruits, nuts, spices, vegetables, and fungi (where their concentration depends on the nature of the plant species, the growing season, plant survival, and reproduction). They may also be formed as a by-product of microbial activity. 
It has been reported that some benzoic acid–derived compounds have potential antiarthritic effects. 
Gallic acid (3,4,5-trihydroxybenzoic acid) (1), a natural phenolic acid present in gall nuts, oak bark, and grapes, has a proapoptotic effect on fibroblast-like synoviocytes (FLS) of RA patients. Gallic acid stimulates apoptosis in RA-FLS by modulating the expression of several apoptosis-related proteins such as Bax, Bcl-2, and caspase-3. 
Moreover, gallic acid suppresses the production of various proinflammatory cytokines (IL-1β and IL-6), chemokines (chemokine [C–C motif] ligand [CCL]-2/monocyte chemoattractant protein [MCP]-1 and CCL-7/MCP-3) and RA-inducing enzymes such as COX-2 and MMP-9 (del Olmo et al., 2017). 
Oral administration of methyl gallate (methyl ester of gallic acid) inhibited IL-6, TNF-α production, and neutrophil chemotaxis by downregulating chemokine receptor (CXCL)1 expression in zymosan-induced experimental arthritis models (Yoon et al., 2013a). 
It reduced the production of nitric oxide (NO), COX-2, and inducible nitric oxide synthase (iNOS). 
It also inhibited the mobilization of intracellular calcium.
Treatment with protocatechuic acid (2), an antioxidant polyphenol in green tea, significantly inhibited osteoclast differentiation and induced mature osteoclast apoptosis by downregulating the expression of various osteoclast specific markers (MMP, c-Src, TRAF-6, Cathepsin, etc.) and by inhibiting transcription factor AP-1 and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) expression. 
Furthermore, it induced disruption of mitochondrial membrane potential and cytochrome C–mediated caspase activation. 
It also repressed the modulation of ERK1/2 (MAPK) pathway as well as inflammatory proteins such as NF-кB and COX-2 and enhanced nuclear factor erythroid 2–related factor 2 expression in murine macrophage RAW264.7.6 cells (Wu et al., 2016). In an adjuvant-induced arthritis (AIA) rat model, protocatechuic acid treatment considerably lowered the score of paw swelling and restored antioxidant enzyme expression (such as superoxide dismutase [SOD], catalase and glutathione) in the liver of arthritic rats (Lende et al., 2011). 

A fungistatic compound that is widely used as a food preservative. 
It is conjugated to GLYCINE in the liver and excreted as hippuric acid. 
As the sodium salt form, sodium benzoate is used as a treatment for urea cycle disorders due to its ability to bind amino acids. 
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. 
Total Positive and Negative Syndrome Scale scores dropped by 21% compared to placebo.


Benzoic acid is a white (or colorless) solid with the formula C6H5CO2H. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, which was for a long time its only source. Benzoic acid occurs naturally in many plants and serves as an intermediate in the biosynthesis of many secondary metabolites. Salts of benzoic acid are used as food preservatives. Benzoic acid is an important precursor for the industrial synthesis of many other organic substances. The salts and esters of benzoic acid are known as benzoates .


Synonyms     
acide benzoïque Français    
Aromatic carboxylic acid    
Benzenecarboxylic acid    
Benzeneformic acid    
Benzenemethanoic acid    
Benzoesäure Deutsch    
Benzoic acid    
BENZOIC ACID    
Dracylic acid    
E210    
Phenylcarboxylic acid    
Phenylformic acid    

Roles Classification 
Chemical Role(s):    Bronsted acid
A molecular entity capable of donating a hydron to an acceptor (Bronsted base).
(via oxoacid )

Biological Role(s):    algal metabolite
Any eukaryotic metabolite produced during a metabolic reaction in algae including unicellular organisms like chlorella and diatoms to multicellular organisms like giant kelps and brown algae.

EC 3.1.1.3 (triacylglycerol lipase) inhibitor
Any EC 3.1.1.* (carboxylic ester hydrolase) inhibitor that inhibits the action of triacylglycerol lipase (EC 3.1.1.3).

antimicrobial food preservative
A food preservative which prevents decomposition of food by preventing the growth of fungi or bacteria. In European countries, E-numbers for permitted food preservatives are from E200 to E299, divided into sorbates (E200-209), benzoates (E210-219), sulfites (E220-229), phenols and formates (E230-239), nitrates (E240-259), acetates (E260-269), lactates (E270-279), propionates (E280-289) and others (E290-299).

drug allergen
Any drug which causes the onset of an allergic reaction.
EC 1.13.11.33 (arachidonate 15-lipoxygenase) inhibitor
A lipoxygenase inhibitor that interferes with the action of arachidonate 15-lipoxygenase (EC 1.13.11.33).

plant metabolite
Any eukaryotic metabolite produced during a metabolic reaction in plants, the kingdom that include flowering plants, conifers and other gymnosperms.
human xenobiotic metabolite
Any human metabolite produced by metabolism of a xenobiotic compound in humans.

Application(s):    antimicrobial food preservative
A food preservative which prevents decomposition of food by preventing the growth of fungi or bacteria. 
In European countries, E-numbers for permitted food preservatives are from E200 to E299, divided into sorbates (E200-209), benzoates (E210-219), sulfites (E220-229), phenols and formates (E230-239), nitrates (E240-259), acetates (E260-269), lactates (E270-279), propionates (E280-289) and others (E290-299).
drug allergen
Any drug which causes the onset of an allergic reaction.

Translated names
Acid benzoic (ro)
Acide benzoïque (fr)
acide benzoïque (fr)
Acido benzoico (it)
Aċidu benżojku (mt)
Bensoehape (et)
Bensoesyra (sv)
Bentsoehappo (fi)
Benzenkarboksirūgštis (lt)
Benzoe-säure (de)
Benzoesav (hu)
Benzoesyre (da)
Benzoic acid (no)
Benzojeva kiselina (hr)
Benzojska kislina (sl)
Benzoová kyselina (cs)
Benzoskābe (lv)
benzosyre (no)
Benzoëzuur (nl)
Kwas benzoesowy (pl)
Kyselina benzoová (sk)
Ácido benzoico (es)
Ácido benzoico (pt)
Βενζοϊκό οξύ (el)
Бензоена киселина (bg)

CAS names
Benzoic acid


IUPAC names
benzene carboxylic acid
Benzenecarboxylic acid
Benzoesäure
BENZOIC ACID
Benzoic Acid
Benzoic Acid Zone Refined (number of passes:20)
Benzonic acid
Phenylformic acid, Benzene carboxylic acid


Benzoic acid is rarely used as such in medicines whereas its salts (benzoates) are more commonly used. 
Sodium benzoate is found as excipients in some medicinal products administered orally, topically(e.g. antifungals) or injected.
Benzoic acid has a long history of use as an antifungal agent in topical therapeutic preparations such as Whitfield's ointment (benzoic acid 6% and salicylic acid 3%). 
Sodium benzoate is also administered intravenously and orally as an active substance to infants and children for the treatment of hyperammonaemia related to urea cycle disorders

E210: benzoic acid
E211: sodium benzoate
E212: potassium benzoate

Benzoic acid, C6H5COOH, is a colourless crystalline solid and the simplest aromatic carboxylic acid. 
Benzoic acid occurs naturally free and bound as benzoic acid esters in many plant and animal species. 
Appreciable amounts have been found in most berries (around 0.05%). Cranberries contain as much as 300-1300 mg free benzoic acid per kg fruit. 
Benzoic acid is a fungistatic compound that is widely used as a food preservative. It often is conjugated to glycine in the liver and excreted as hippuric acid. 
Benzoic acid is a byproduct of phenylalanine metabolism in bacteria. It is also produced when gut bacteria process polyphenols (from ingested fruits or beverages). 
It can be found in Serratia (PMID: 23061754 ).


Acide benzoique    
Aromatic carboxylic acid    
Benzenecarboxylic acid    
Benzeneformic acid    
Benzenemethanoic acid    
Benzoesaeure    
Dracylic acid    
e210    
Phenylcarboxylic acid    
Phenylformic acid    
Aromatic carboxylate    
Benzenecarboxylate    
Benzeneformate    
Benzenemethanoate    
Dracylate    
Phenylcarboxylate    
Phenylformate    
Benzoate    
Benzenemethonic acid    
Benzoic acid sodium salt    
Carboxybenzene    
Diacylate    
Diacylic acid    
Oracylic acid    
Sodium benzoate    
Sodium benzoic acid    
Acid, benzoic    
Kendall brand OF benzoic acid sodium salt    
Benzoate, potassium    
Potassium benzoate    
Ucephan

As a kind of antibacterial and antifungal preservative, benzoic acid is widely used in foods and feeds. Recently, many studies showed that it could improve the growth and health, which should, at least partially, be derived from the promotion of gut functions, including digestion, absorption, and barrier. Based on the similarity of gut physiology between human and pigs, many relative studies in which piglets and porcine intestinal epithelial cells were used as the models have been done. And the results showed that using appropriate benzoic acid levels might improve gut functions via regulating enzyme activity, redox status, immunity, and microbiota, but excess administration would lead to the damage of gut health through redox status. However, the further mechanisms that some intestinal physiological functions might be regulated are not well understood. The present review will, in detail, summarize the effect of benzoic acid on gut functions.

Use: Preservative in food and pharmaceutical applications to inhibit microbial growth at the optimum pH of 2.5-4.0. Main uses are preparations such as mouthwashes, lotions and toothpastes.

Use: Benzoic acid is a mono-functional, aromatic acid, which is widely used as a building block for the synthesis of alkyd resins. It is also used as a preservative in select industrial applications. When used as a component of alkyd resins, it improves gloss, hardness and chemical resistance. When used as a preservative, benzoic acid increases storage stability and reduces corrosion for emulsions, polishes, waxes, paints and liquid detergents.

Use: Emerald Kalama facility in Rotterdam EU is one of the world's largest benzoic acid purification units and focused on high purity benzoic acid. 
Purox® B Food/Pharma grade meets the Ph.Eur, USP/NF, FCC and JP requirements. 
It stands out because of its low impurity content, which has earned it a classification as user friendly. 
Purox® B Food/Pharma has a low odor level and low agglomeration tendency and gives an improved color of the end product. 
In the synthesis of high-purity chemical intermediates for the food, cosmetic and pharmaceutical industries only the purest grades of benzoic acid can be used. 
Purox® B Food/Pharma meets all the requirements for these applications. 
Use of this new grade eliminates the need to apply complex and costly purification techniques to remove impurities introduced by less pure starting materials.

Synonyms:
     benzene carboxylic acid
     benzene formic acid
     benzene methanoic acid
     benzenecarboxylic acid
     benzeneformic acid
     benzenemethanoic acid
nat.    benzoic acid
     benzoic acid crystal FCC
     benzoic acid natural
     benzoic acid U.S.P.
     benzoic acid USP FCC granular
     benzoic acid USP/EP/JP
     carboxybenzene
     diacylic acid
     dracyclic acid
     dracylic acid
     oracylic acid
     phenyl carboxylic acid
     phenyl formic acid
     phenylcarbinolum
     phenylcarboxylic acid
     phenylformic acid
     retardex
     tenn-plas
     unisept BZA

Benzoic acid, C6H5COOH, is a colourless crystalline solid and the simplest aromatic carboxylic acid. Benzoic acid occurs naturally free and bound as benzoic acid esters in many plant and animal species. Appreciable amounts have been found in most berries (around 0.05%). Cranberries contain as much as 300-1300 mg free benzoic acid per kg fruit. Benzoic acid is a fungistatic compound that is widely used as a food preservative. Benzoic acid is a byproduct of phenylalanine metabolism in bacteria. It is also produced when gut bacteria process polyphenols (from ingested fruits or beverages).


Synonyms    
Benzenecarboxylic acid
Benzeneformate
Benzeneformic acid
Benzenemethanoate
Benzenemethanoic acid
Benzenemethonic acid
Benzoate
benzoic acid
Benzoic acid sodium salt
Carboxybenzene
Diacylate
Diacylic acid
Dracylate
Dracylic acid
Oracylic acid
Phenylcarboxylate
Phenylcarboxylic acid
Phenylformate
Phenylformic acid
Sodium benzoate
Sodium benzoic acid
Benzenecarboxylate
Acide benzoique
Aromatic carboxylic acid
Benzenecarboxylic acid
Benzeneformic acid
Benzenemethanoic acid
Benzoesaeure
Dracylic acid
e210
Phenylcarboxylic acid
Phenylformic acid
Aromatic carboxylate
Benzeneformate
Benzenemethanoate
Dracylate
Phenylcarboxylate
Phenylformate
Benzoate
Benzenemethonic acid
Benzoic acid sodium salt
Carboxybenzene
Diacylate
Diacylic acid
Oracylic acid
Sodium benzoate
Sodium benzoic acid
Acid, benzoic
Kendall brand OF benzoic acid sodium salt
Benzoate, potassium
Potassium benzoate
Ucephan

[Code of Federal Regulations]
[Title 21, Volume 3]
[Revised as of April 1, 2020]
[CITE: 21CFR184.1021]

TITLE 21--FOOD AND DRUGS
CHAPTER I--FOOD AND DRUG ADMINISTRATION
DEPARTMENT OF HEALTH AND HUMAN SERVICES
SUBCHAPTER B - FOOD FOR HUMAN CONSUMPTION (CONTINUED)
PART 184 -- DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE

Subpart B - Listing of Specific Substances Affirmed as GRAS

Sec. 184.1021 Benzoic acid.
(a) benzoic acid is the chemical benzenecarboxylic acid (C7H6O2), occurring in nature in free and combined forms. Among the foods in which benzoic acid occurs naturally are cranberries, prunes, plums, cinnamon, ripe cloves, and most berries. benzoic acid is manufactured by treating molten phthalic anhydride with steam in the presence of a zinc oxide catalyst, by the hydrolysis of benzotrichloride, or by the oxidation of toluene with nitric acid or sodium bichromate or with air in the presence of a transition metal salt catalyst.

(b) The ingredient meets the specifications of the "Food Chemicals Codex," 3d Ed. (1981), p. 35, which is incorporated by reference. Copies may be obtained from the National Academy Press, 2101 Constitution Ave. NW., Washington, DC 20418, or may be examined at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

(c) The ingredient is used as an antimicrobial agent as defined in § 170.3(o)(2) of this chapter, and as a flavoring agent and adjuvant as defined in § 170.3(o)(12) of this chapter.

(d) The ingredient is used in food at levels not to exceed good manufacturing practice. Current usage results in a maximum level of 0.1 percent in food. (The Food and Drug Administration has not determined whether significantly different conditions of use would be GRAS).

(e) Prior sanctions for this ingredient different from those uses established in this section, or different from that set forth in part 181 of this chapter, do not exist or have been waived.

[42 FR 14653, Mar. 15, 1977, as amended at 49 FR 5610, Feb. 14, 1984]

Benzoic acid is a solid that is crystalline in appearance, similar to white needles. 
A natural source of benzoic acid is gum benzoin, which comes from certain tree barks; however, benzoic acid can also be made by synthetic means.

The chemical formula of benzoic acid is C7H6O2: it has seven carbon (C) atoms, six hydrogen (H) atoms and two oxygen (O) atoms. 
This chemical formula can also be written as C6H5COOH. The chemical structure of carboxylic acid is shown here. 
On the left, we see that all the carbon and hydrogen atoms on the benzene ring are drawn out, and on the right, we see the shorthand way to draw a benzene ring (in blue).

Benzoic acid is an organic compound because it contains carbon, and it is also an aromatic carboxylic acid. 
It is aromatic because it has a benzene ring in its chemical structure. Benzene is aromatic because it has alternating double bonds between each carbon. 
It's classified as a carboxylic acid because it has a carboxyl group in its structure, which is the COOH group boxed in red.

Common Uses - Preservative
Benzoic acid is very useful in the food industry, personal care industry and in medicine as well


Benzoic acid is a plant polyphenol and a natural aromatic acid used in a wide variety of cosmetics as a pH adjuster and preservative. 
Benzyl Alcohol is metabolized to Benzoic Acid in the body.
Benzoic acid was originally found as a by-product of the distillation of gum benzoin during the 1600th century. 
Now it is mostly commercially manufactured from toluene.
Benzoic acid often appears in a cosmetic formulation as Sodium benzoate, the inactive salt of a benzoic acid which is soluble in water. 
At low pH levels in water, sodium benzoate converts to benzoic acid, the active form. 
The activity of benzoic acid is very pH dependent, showing low activity above pH 6 and most active at pH 3.

As a preservative in cosmetic formulations, it is primarily an anti-fungal agent that prevents fungi from developing in products and formulas and changing their composition. 
It is less effective against bacteria.
Benzoic acid has a long history of use as an antifungal agent in topical therapeutic preparations such as Whitfield’s ointment (benzoic acid 6% and salicylic acid 3%). 
It has been used with salicylic acid as a topical antifungal agent and in the treatment of athletes foot and ringworm.
When Sodium benzoate is used as a preservative, the pH of the final formulation may have to be lowered to facilitate the release of the free benzoic acid for useful activity.  
Potassium sorbate is often combined with Sodium benzoate in low pH products to provide a synergistic preservative effect against yeast and mold.
It has been concluded that benzoic acid can be used safely at concentrations up to 5%, but that consideration should be given the nonimmunologic phenomena when using this ingredient in cosmetic formulations designed for infants and children.

Conclusions
Benzoic acid is an aromatic acid used in a wide variety of cosmetics as a pH adjuster and preservative. 
Benzoic acid has a long history of use as an antifungal agent in topical therapeutic preparations. 
It has been concluded that benzoic acid can be used safely at concentrations up to 5%, but that consideration should be given the nonimmunologic phenomena when using this ingredient in cosmetic formulations designed for infants and children.

History
Benzoic acid was discovered in the 16th century. The dry distillation of gum benzoin was first described by Nostradamus (1556), and subsequently by Alexius Pedemontanus (1560) and Blaise de Vigenère (1596).[1]

Justus von Liebig and Friedrich Wöhler determined the structure of benzoic acid in 1832.[2] They also investigated how hippuric acid is related to benzoic acid.

In 1875 Salkowski discovered the antifungal abilities of benzoic acid, which were used for a long time in the preservation of benzoate containing fruits.[3]

Production
Industrial preparations
Benzoic acid is produced commercially by partial oxidation of toluene with oxygen. The process is catalyzed by cobalt or manganese naphthenates. The process uses cheap raw materials, proceeds in high yield, and is considered environmentally green.


U.S. production capacity is estimated to be 126,000 tonnes per year (139,000 tons), much of which is consumed domestically to prepare other industrial chemicals.

Historical preparations
The first industrial process involved the reaction of benzotrichloride (trichloromethyl benzene) with calcium hydroxide in water, using iron or iron salts as catalyst. The resulting calcium benzoate is converted to benzoic acid with hydrochloric acid. The product contains significant amounts of chlorinated benzoic acid derivatives. For this reason, benzoic acid for human consumption was obtained by dry distillation of gum benzoin. Food-grade benzoic acid is now produced synthetically.[4]

Alkyl substituted benzene derivatives give benzoic acid with the stoichiometric oxidants potassium permanganate, chromium trioxide, nitric acid.

Uses
Food preservative
Benzoic acid and its salts are used as a food preservative, represented by the E-numbers E210, E211, E212, and E213. Benzoic acid inhibits the growth of mold, yeast[5] and some bacteria. It is either added directly or created from reactions with its sodium, potassium, or calcium salt. The mechanism starts with the absorption of benzoic acid in to the cell. If the intracellular pH changes to 5 or lower, the anaerobic fermentation of glucose through phosphofructokinase is decreased by 95%. The efficacy of benzoic acid and benzoate is thus dependent on the pH of the food.[6] Acidic food and beverage like fruit juice (citric acid), sparkling drinks (carbon dioxide), soft drinks (phosphoric acid), pickles (vinegar) or other acidified food are preserved with benzoic acid and benzoates.

Typical levels of use for benzoic acid as a preservative in food are between 0.05 – 0.1%. Foods in which benzoic acid may be used and maximum levels for its application are laid down in international food law.[7][8]

Concern has been expressed that benzoic acid and its salts may react with ascorbic acid (vitamin C) in some soft drinks, forming small quantities of benzene.[9][10]

See also: Benzene in soft drinks
Synthesis
Benzoic acid is used to make a large number of chemicals, important examples of which are:

Benzoyl chloride, C6H5C(O)Cl, is obtained by treatment of benzoic with thionyl chloride, phosgene or one of the chlorides of phosphorus. C6H5C(O)Cl is an important starting material for several benzoic acid derivates like benzyl benzoate, which is used as artificial flavours and insect repellents.
Benzoyl peroxide, [C6H5C(O)O]2, is obtained by treatment with peroxide.[11] The peroxide is a radical starter in polymerization reactions and also a component in cosmetic products.
Benzoate plasticizers, such as the glycol-, diethylengylcol-, and triethyleneglycol esters are obtained by transesterification of methyl benzoate with the corresponding diol. Alternatively these species arise by treatment of benzoylchloride with the diol. These plasticizers are used similarly to those derived from terephthalic acid ester.
Phenol, C6H5OH, is obtained by oxidative decarboxylation at 300-400°C. The temperature required can be lowered to 200°C by the addition of catalytic amounts of copper(II) salts. The phenol can be converted to cyclohexanol, which is a starting material for nylon synthesis.
Medicinal
Benzoic acid is a constituent of Whitfield Ointment which is used for the treatment of fungal skin diseases such as tinea, ringworm, and athlete's foot. [12] [13]

Purification
Benzoic acid is purified by recrystallisation of the crude product. This involves dissolving the material and allowing it to recrystallize (or re-solidify), leaving any impurities in solution and allowing the pure material to be isolated from the solution. [14]

Biology and health effects
Benzoic acid occurs naturally free and bound as benzoic acid esters in many plant and animal species. Appreciable amounts have been found in most berries (around 0.05%). Ripe fruits of several Vaccinium species (e.g., cranberry, V. vitis idaea; bilberry, V. macrocarpon) contain as much as 300-1300 mg free benzoic acid per kg fruit. Benzoic acid is also formed in apples after infection with the fungus Nectria galligena. Among animals, benzoic acid has been identified primarily in omnivorous or phytophageous species, e.g., in viscera and muscles of the ptarmigan (Lagopus mutus) as well as in gland secretions of male muskoxen (Ovibos moschatus) or Asian bull elephants (Elephas maximus).[15]

Gum benzoin contains up to 20% of benzoic acid and 40% benzoic acid esters.[16]

Benzoic acid is present as part of hippuric acid (N-Benzoylglycine) in urine of mammals, especially herbivores (Gr. hippos = horse; ouron = urine). Humans produce about 0.44 g/L hippuric acid per day in their urine, and if the person is exposed to toluene or benzoic acid it can rise above that level.[17]

For humans ,the WHO's International Programme on Chemical Safety (IPCS) suggests a provisional tolerable intake would be 5 mg/kg body weight per day.[15] Cats have a significantly lower tolerance against benzoic acid and its salts than rats and mice. Lethal dose for cats can be as low as 300 mg/kg body weight.[18] The oral LD50 for rats is 3040 mg/kg, for mice it is 1940-2263 mg/kg.[15]

Chemistry
Reactions of benzoic acid can occur at either the aromatic ring or the carboxylic group:

Aromatic ring

Electrophilic aromatic substitution reaction will take place mainly in 3-position to the electron-withdrawing carboxylic group.

The second substitution reaction (on the right) is slower because the first nitro group is deactivating.[19] Conversely, if an activating group (electron-donating) was introduced (e.g., alkyl), a second substitution reaction would occur more readily than the first and the disubstituted product might not accumulate to a significant extent.

Carboxylic group
All the reactions mentioned for carboxylic acids are also possible for benzoic acid.

Benzoic acid esters are the product of the acid catalysed reaction with alcohols.
Benzoic acid amides are more easily available by using activated acid derivatives (such as benzoyl chloride) or by coupling reagents used in peptide synthesis like DCC and DMAP.
The more active benzoic anhydride is formed by dehydration using acetic anhydride or phosphorus pentoxide.
Highly reactive acid derivatives such as acid halides are easily obtained by mixing with halogenation agents like phosphorus chlorides or thionyl chloride.
Orthoesters can be obtained by the reaction of alcohols under acidic water free conditions with benzonitrile.
Reduction to benzaldehyde and benzyl alcohol is possible using DIBAL-H, LiAlH4 or sodium borohydride.
The copper catalysed decarboxylation of benzoate to benzene may be effected by heating in quinoline. Also, Hunsdiecker decoarboxylation can be achieved by forming the silver salt and heating.

Laboratory preparations
Benzoic acid is cheap and readily available, so the laboratory synthesis of benzoic acid is mainly practiced for its pedogical value. It is a common undergraduate preparation and a convenient property of the compound is that its melting point equals its molecular weight (122). For all syntheses, benzoic acid can be purified by recrystallization from water because of its high solubility in hot water and poor solubility in cold water. The avoidance of organic solvents for the recrystallization makes this experiment particularly safe.

By hydrolysis
Like any other nitrile or amide, benzonitrile and benzamide can be hydrolyzed to benzoic acid or its conjugate base in acid or basic conditions.

From benzaldehyde
The base-induced disproportionation of benzaldehyde, the Cannizzaro reaction, affords equal amounts of benzoate and benzyl alcohol; the latter can be removed by distillation.


From bromobenzene
Bromobenzene in diethyl ether is stirred with magnesium turnings to produce phenylmagnesium bromide (C6H5MgBr). This Grignard reagent is slowly added to dry-ice (solid carbon dioxide) to give benzoate. Dilute acid is added to form benzoic acid.


From benzyl alcohol
Benzyl alcohol is refluxed with potassium permanganate or other oxidizing reagents in water. The mixture hot filtered to remove manganese oxide and then allowed to cool to afford benzoic acid.


MARKET PERSPECTIVE

Benzoate plasticizers (primarily dibenzoate esters) are used mainly in polyvinyl acetate (PVA)-based emulsion adhesives, caulks and sealants. Benzoates impart flexibility to PVA emulsion and increase its adhesion to nonporous substrates such as film, foil and coated paper. Dibenzoates compete with phthalate plasticizers in these applications. But dibenzoates have better growth prospects than the phthalates, partly as a result of continuing environmental pressure on phthalates and as dibenzoates replace phthalates in certain other applications. This sector represents nearly 50% of benzoic acid's demand, and it is the most robust, growing by more than 2.5%/year. This is slightly ahead of GDP growth.

Sodium and potassium benzoates are used as preservatives in a variety of foods and beverages. This segment matches GDP growth and accounts for about one-quarter of benzoic acid's demand.

Benzoic acid improves the hardness, gloss, adhesion and chemical resistance of alkyd resin surface coatings. Demand for alkyd surface coatings has been negatively influenced by clean air regulations limiting the level of volatile organic compounds in these products. Substitute coating technologies, particularly acrylic latexes and to a smaller degree epoxies, urethanes, polyesters and vinyls, are contributing to a slowly declining situation. The decline is about 1%/year.
 

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