BENZOIC ACID

BENZOIC ACID
DESCRIPTION

Benzoic acid - colorless crystals, poorly soluble in water, well - in ethanol and diethyl ether. Benzoic acid is, like most other organic acids, a weak acid

Molecular structure:  benzoic acid C6H5COOH is the simplest monobasic carboxylic acid of the aromatic series.

Application:  used as a raw material in the paint and varnish industry.

SPECIFICATIONS
Appearance: Flakes
Colour: White
Smell: Characteristic
Main substance content: 99.98%
Water content (determination by Karl Fischer method) : 0.1%
Boiling point (° C): 249.2 ° C at 760 mm Hg
Melting point (° C): 122.4 ° C at 101,325 Pa 
pH: 2.8 at 25 ° C (saturated solution) 
Storage: No special storage conditions required. Keep away from heat sources. Store in original tightly closed containers in a cool, well-ventilated place and in tightly closed containers after use. The shelf life is about 24 months in the original packaging, there is a tendency for agglomeration.

Transport information: Not classified as dangerous.

Benzoic acid /bɛnˈzoʊ.ɪk/ 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[9] 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.

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).

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

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% 

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.[16][17][18][19][20]

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 + 1/2O2 → 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. 
Alternatively these species arise by treatment of benzoyl chloride with the diol. These plasticizers are used similarly to those derived from terephthalic acid ester.

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 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 0.05–0.1%. 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.

See also: Benzene in soft drinks
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.

Benzoyl chloride
Benzoic acid is a precursor to benzoyl chloride, C6H5C(O)Cl by treatment with thionyl chloride, phosgene or one of the chlorides of phosphorus. Benzoyl chloride is an important
 starting material for several benzoic acid derivates like benzyl benzoate, which is used in artificial flavours and insect repellents.

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.

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:

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.

Safety and mammalian metabolism
It is excreted as hippuric acid. Benzoic acid is metabolized by butyrate-CoA ligase into an intermediate product, benzoyl-CoA, which is then metabolized by glycine N-acyltransferase 
into hippuric acid. Humans metabolize toluene and benzoic acid which is excreted as hippuric acid.

For humans, the World Health Organization's International Programme on Chemical Safety (IPCS) suggests a provisional tolerable intake would be 5 mg/kg body weight per day.
 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.The oral LD50 for rats
 is 3040 mg/kg, for mice it is 1940–2263 mg/kg.

In Taipei, Taiwan, a city health survey in 2010 found that 30% of dried and pickled food products had benzoic acid.

Benzoic acid, also known as benzoate or E210, belongs to the class of organic compounds known as benzoic acids. These are organic Compounds containing a benzene ring which bears at 
least one carboxyl group. Benzoic acid exists as a solid, slightly soluble (in water), and a weakly acidic compound (based on its pKa). Benzoic acid has been found throughout most 
human tissues, and has also been detected in most biofluids, including saliva, feces, urine, and sweat. Within the cell, benzoic acid is primarily located in the cytoplasm and 
endoplasmic reticulum. Benzoic acid exists in all eukaryotes, ranging from yeast to humans. Benzoic acid is also a parent compound for other transformation products, including but
 not limited to, 4-(2-carboxyphenyl)-2-oxobut-3-enoic acid, 4-hydroxy-3-octaprenylbenzoic acid, and hydroxybenzoic acid. Benzoic acid is a potentially toxic compound.

Benzoic acid appears as a white crystalline solid. Slightly soluble in water. The primary hazard is the potential for environmental damage if released. Immediate steps should be taken
 to limit spread to the environment. Used to make other chemicals, as a food preservative, and for other uses.

Benzoic acid is a compound comprising a benzene ring core carrying a carboxylic acid substituent. It 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.
 It is a conjugate acid of a benzoate.
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]
Diacylate
Salvo, liquid
Solvo, powder
AI3-03710
Benzoic acid [USAN:JAN]
phenyl formic acid
EPA Pesticide Chemical Code 009101
Benzoic acid Natural
C7H6O2
E210
Aromatic carboxylic acid
EINECS 200-618-2
Benzeneformate
Tennplas
Benzenemethanoate
Phenylcarboxylate
Benzenecarboxylate
Retarded BA
Benzoicacid
(2H5)Benzoic acid
Phenyl carboxylic acid
Benzoic acid, 99%, extra pure
Acido benzoico
Benzoic acid, 99.5%, for analysis
Benzoic acid, 99.6%, ACS reagent
Carboxypolystyrene
CAS-65-85-0
NSC7918
Benzoic acid, tech
Benzoic acid (TN)
Benzoic acid [USP:JAN]
phenylcarboxy
Dracylate
benzoic aicd
bezoic acid
Aromatic acid
benzenecarboxylic
Salvo powder
benzoic- acid
Benzoic Acid.
Benzoic Acid USP
Sodium benzoic acid
Benzoic Acid,(S)
Natural Benzoic Acid
Benzoic acid,medicinal
Benzoic acid / Benzoate
benzene-2-carboxylic acid
Benzoic acid, ACS reagent
200-618-2 [EINECS]
636131 [Beilstein]
65-85-0 [RN]
Acide benzoique [French]
Acide benzoïque [French] [ACD/IUPAC Name]
Acido benzoico [Italian]
Acidum benzoicum [Latin]
Alcohol bencílico [Spanish] [INN]
Benzenecarboxylic acid
benzeneformic acid
Benzenemethanoic acid
Benzoesaeure [German]
Benzoesäure [German] [ACD/IUPAC Name]
Benzoic acid [ACD/Index Name] [ACD/IUPAC Name] [USP] [Wiki]
MFCD00198115 [MDL number]
QVR [WLN]
苯甲酸 [Chinese]
Acidum benzoicum
benzenemethonic acid
Benzoic acid 100 µg/mL in Acetone
Benzoic acid 100 µg/mL in Acetonitrile
Benzoic acid, ACS reagent
BS-3752
Carboxybenzene
DB03793
Diacylic acid
Dracylic acid
Euxyl K 100
Oracylic acid
Phenolcarbinol
Phenylcarboxy
PHENYLCARBOXYLIC ACID
Phenylformic acid
Retarder BAX
Retardex
Tenn-Plas
UCEPHAN
Unisept BZA