Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Benzoic acid: Difference between pages

{{short description|Organic compound (C6H5COOH)}}

{{redirect|E210|the car|Toyota Corolla (E210)}}{{Use dmy dates|date=February 2021}}

| Watchedfields = changed

| verifiedrevid = 476995928

| ImageFileL1 = Benzoesäure.svg

| ImageSizeL1 = 100px

| ImageNameL1 = Skeletal formula

| ImageFileR1 = Benzoic-acid-3D-balls.png

| ImageSizeR1 = 100px

| ImageNameR1 = Ball-and-stick model

| ImageFile2 = Pile of benzoic acid crystals.jpg

| ImageSize2 = 270px

| PIN = Benzoic acid<ref name=iupac2013>{{cite book | title = Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = [[Royal Society of Chemistry|The Royal Society of Chemistry]] | date = 2014 | location = Cambridge | page = 745 | doi = 10.1039/9781849733069-00648 | isbn = 978-0-85404-182-4 }}</ref>

| SystematicName = Benzenecarboxylic acid

| OtherNames = {{ubl

| Carboxybenzene

| E210

| Dracylic acid

| Phenylmethanoic acid

| Phenylcarboxylic acid

| Benzoyl alcohol

| Benzoylic acid

| Carboxylbenzene

| Hydrogenphenic acid

| Phenoic acid

}}

| Section1 = {{Chembox Identifiers

| ChemSpiderID = 238

}}

| Section2 = {{Chembox Properties

| C=7 | H=6 | O=2

| MolarMassUnit = g/mol

| Appearance = Colorless crystalline solid

| Odor = Faint, pleasant odor

| Density = 1.2659{{nbsp}}g/cm³ (15&nbsp;°C)<br> 1.0749{{nbsp}}g/cm³ (130&nbsp;°C)<ref name=chemister />

| MeltingPtC = 122

| MeltingPt_ref =<ref name=GESTIS/>

| BoilingPtC = 250

| BoilingPt_ref =<ref name=GESTIS>{{GESTIS|ZVG=22810}}</ref>

| Solubility = 1.7{{nbsp}}g/L (0&nbsp;°C)<br> 2.7{{nbsp}}g/L (18&nbsp;°C)<br> 3.44{{nbsp}}g/L (25&nbsp;°C)<br> 5.51{{nbsp}}g/L (40&nbsp;°C)<br> 21.45{{nbsp}}g/L (75&nbsp;°C)<br> 56.31{{nbsp}}g/L (100&nbsp;°C)<ref name=chemister>{{cite web|url=http://chemister.ru/Database/properties-en.php?dbid=1&id=679|title=benzoic acid|website=chemister.ru|access-date=24 October 2018}}</ref><ref name=sioc>{{cite book|last1 = Seidell|first1 = Atherton|last2 = Linke|first2 = William F.|year = 1952|title = Solubilities of Inorganic and Organic Compounds|publisher = Van Nostrand|url = https://books.google.com/books?id=k2e5AAAAIAAJ}}</ref>

| pKa = {{ubl

| 4.202 (H₂O)<ref>{{cite book|last=Harris|first=Daniel|title=Quantitative Chemical Analysis|year=2010|publisher=W. H. Freeman and Company|location=New York|isbn=9781429254366|pages=AP12|edition=8}}</ref>

| 11.02 (DMSO)<ref>{{cite journal |last1=Olmstead |first1=William N. |last2=Bordwell |first2=Frederick G. |title=Ion-pair association constants in dimethyl sulfoxide |journal=The Journal of Organic Chemistry |date=1980 |volume=45 |issue=16 |pages=3299–3305 |doi=10.1021/jo01304a033}}</ref>

}}

| SolubleOther = Soluble in [[acetone]], [[benzene]], [[carbon tetrachloride|CCl₄]], [[chloroform|CHCl₃]], [[ethanol|alcohol]], [[ethyl ether]], [[hexane]], [[phenyl]]s, liquid [[ammonia]], [[acetate]]s

| Solubility1 = 30{{nbsp}}g/100{{nnbsp}}g (−18&nbsp;°C)<br> 32.1{{nbsp}}g/100{{nnbsp}}g (−13&nbsp;°C)<br> 71.5{{nbsp}}g/100{{nnbsp}}g (23&nbsp;°C)<ref name=chemister />

| Solvent1 = methanol

| Solubility2 = 25.4{{nbsp}}g/100{{nnbsp}}g (−18&nbsp;°C)<br> 47.1{{nbsp}}g/100{{nnbsp}}g (15&nbsp;°C)<br> 52.4{{nbsp}}g/100{{nnbsp}}g (19.2&nbsp;°C)<br> 55.9{{nbsp}}g/100{{nnbsp}}g (23&nbsp;°C)<ref name=chemister />

| Solvent2 = ethanol

| Solubility3 = 54.2{{nbsp}}g/100{{nnbsp}}g (20&nbsp;°C)<ref name=chemister />

| Solvent3 = acetone

| Solubility4 = 4.22{{nbsp}}g/100{{nnbsp}}g (25&nbsp;°C)<ref name=chemister />

| Solvent4 = olive oil

| Solubility5 = 55.3{{nbsp}}g/100{{nnbsp}}g (25&nbsp;°C)<ref name=chemister />

| Solvent5 = 1,4-dioxane

| pKb =

| IsoelectricPt =

| LambdaMax =

| Absorbance =

| SpecRotation =

| RefractIndex = 1.5397 (20&nbsp;°C)<br> 1.504 (132&nbsp;°C)<ref name=chemister />

| Viscosity = 1.26{{nbsp}}mPa (130&nbsp;°C)

| VaporPressure = 0.16{{nbsp}}Pa (25&nbsp;°C)<br> 0.19{{nbsp}}kPa (100&nbsp;°C)<br> 22.6{{nbsp}}kPa (200&nbsp;°C)<ref name=nist>{{nist|name=Benzoic acid| id= C65850|accessdate=2014-05-23|mask=FFFF|units=SI}}</ref>

| LogP = 1.87

| MagSus = −70.28·10⁻⁶{{nbsp}}cm³/mol

| Section3 = {{Chembox Structure

| CrystalStruct = [[Monoclinic]]

| Coordination =

| MolShape = [[Plane (geometry)|Planar]]

| Dipole = 1.72{{nbsp}}[[Debye|D]] in [[dioxane]]

| Section4 = {{Chembox Thermochemistry

| DeltaHf = −385.2{{nbsp}}kJ/mol<ref name=chemister />

| DeltaHc = −3228{{nbsp}}kJ/mol<ref name=nist />

| Entropy = 167.6{{nbsp}}J/mol·K<ref name=chemister />

| HeatCapacity = 146.7{{nbsp}}J/mol·K<ref name=nist />

| Section7 = {{Chembox Hazards

| ExternalSDS = [http://hazard.com/msds/mf/baker/baker/files/b1356.htm JT Baker]

| GHSPictograms = {{GHS05}}{{GHS08}}<ref name="sigma">{{Sigma-Aldrich| id= w213101|name=Benzoic acid|accessdate=2014-05-23}}</ref>

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|318|335}}<ref name="sigma" />

| PPhrases = {{P-phrases|261|280|305+351+338}}<ref name="sigma" />

| MainHazards = Irritant

| NFPA-H = 2

| NFPA-F = 1

| NFPA-R = 0

| NFPA-S =

| FlashPtC = 121.5

| FlashPt_ref = <ref name=GESTIS/>

| AutoignitionPtC = 571

| AutoignitionPt_ref = <ref name=GESTIS/>

| ExploLimits =

| PEL =

| LD50 = 1700{{nbsp}}mg/kg (rat, oral)

| Section8 = {{Chembox Related

| OtherAnions =

| OtherCations = [[Sodium benzoate]],<br/>[[Potassium benzoate]]

| OtherFunction = [[Hydroxybenzoic acid]]s<br />[[Aminobenzoic acid]]s,<br />[[Nitrobenzoic acid]]s,<br />[[Phenylacetic acid]]

| OtherFunction_label = [[carboxylic acid]]s

| OtherCompounds = [[Benzaldehyde]],<br />[[Benzyl alcohol]],<br />[[Benzoyl chloride]],<br />[[Benzylamine]],<br />[[Benzamide]],<br />[[Benzonitrile]]

'''Benzoic acid''' {{IPAc-en|b|ɛ|n|ˈ|z|oʊ|.|ɪ|k}} is a white (or colorless) solid [[organic compound]] with the formula {{chem2|C6H5COOH}}, whose [[Chemical structure|structure]] consists of a [[benzene]] ring ({{chem2|C6H6}}) with a [[carboxyl]] ({{chem2|\sC(\dO)OH}}) [[substituent]]. The [[benzoyl]] group is often abbreviated "Bz" (not to be confused with "Bn" which is used for [[benzyl]]), thus benzoic acid is also denoted as BzOH, since the benzoyl group has the formula –{{chem2|C6H5CO}}. It is the simplest [[aromaticity|aromatic]] carboxylic acid. The name is derived from [[benzoin (resin)|gum benzoin]], which was for a long time its only source.

Benzoic acid occurs naturally in many plants<ref>{{cite web | title = Scientists uncover last steps for benzoic acid creation in plants | url = http://www.purdue.edu/newsroom/releases/2012/Q3/scientists-uncover-last-steps-for-benzoic-acid-creation-in-plants.html | publisher = Purdue Agriculture News}}</ref> and serves as an intermediate in the biosynthesis of many [[secondary metabolite]]s. [[salt (chemistry)|Salts]] of benzoic acid are used as [[food preservative]]s. Benzoic acid is an important [[Precursor (chemistry)|precursor]] for the industrial synthesis of many other organic substances. The salts and [[ester]]s of benzoic acid are known as '''benzoates''' {{IPAc-en|ˈ|b|ɛ|n|z|oʊ|.|eɪ|t}}.

== 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).<ref>{{cite book | author= Neumüller O-A | year = 1988| title = Römpps Chemie-Lexikon| edition = 6| publisher = Frankh'sche Verlagshandlung | location = Stuttgart| isbn = 978-3-440-04516-9 | oclc= 50969944 }}</ref>

[[Justus von Liebig]] and [[Friedrich Wöhler]] determined the composition of benzoic acid.<ref>{{cite journal

| author = Liebig J |author2=Wöhler F

| title = Untersuchungen über das Radikal der Benzoesäure

| journal = [[Liebigs Annalen|Annalen der Chemie]]

| year = 1832

| volume = 3

| pages = 249–282

| doi = 10.1002/jlac.18320030302

| issue = 3|hdl=2027/hvd.hxdg3f

|author2-link=Friedrich Wöhler

|author-link=Justus von Liebig

| hdl-access = free

}}</ref> These latter also investigated how [[hippuric acid]] is related to benzoic acid.

In 1875 Salkowski discovered the [[Antifungal medication|antifungal]] properties of benzoic acid, which was used for a long time in the preservation of benzoate-containing [[Cloudberry|cloudberry fruits]].<ref>{{cite journal | author= Salkowski E| journal=Berl Klin Wochenschr| year=1875 | volume=12 | pages=297–298}}</ref>{{Disputed inline|Salkowski reference|date=March 2022}}

== Production ==

=== Industrial preparations ===

Benzoic acid is produced commercially by [[partial oxidation]] of [[toluene]] with [[oxygen]]. The process is catalyzed by [[cobalt]] or [[manganese]] [[naphthenate]]s. The process uses abundant materials, and proceeds in high yield.<ref>{{cite book|last1=Wade|first1=Leroy G.|title=Organic Chemistry|date=2014|publisher=Pearson Education Limited|location=Harlow|isbn=978-1-292-02165-2|page=985|edition=Pearson new international |ref=OrgChem}}</ref>

:[[Image:Benzoic acid-chemical-synthesis-1.svg|center|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 [[Halogenation|chlorinated]] benzoic acid derivatives. For this reason, benzoic acid for human consumption was obtained by dry distillation of [[Benzoin (resin)|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 (chemistry)|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%.<ref>{{cite book | title = Purification of Laboratory Chemicals | url = https://archive.org/details/purificationofla0000perr_n7w5 | url-access = registration | edition = 3rd |author1=D. D. Perrin |author2=W. L. F. Armarego | publisher = Pergamon Press | pages = [https://archive.org/details/purificationofla0000perr_n7w5/page/94 94] | year = 1988 | isbn = 978-0-08-034715-8}}</ref>

==== By hydrolysis ====

Like other [[nitrile]]s and [[amide]]s, [[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]].<ref>{{cite book|title=Introduction to Organic Laboratory Techniques: A Small Scale Approach|author=Donald L. Pavia|year=2004|publisher=Thomson Brooks/Cole|isbn=978-0-534-40833-6|pages=312–314}}</ref> 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.<ref>{{cite journal|last=Shirley|first=D. A.|year=1954|title=The Synthesis of Ketones from Acid Halides and Organometallic Compounds of Magnesium, Zinc, and Cadmium|journal=[[Org. React.]]|volume=8|pages=28–58}}</ref><ref>{{cite book|last=Huryn|first=D. M.|year=1991|title=Comprehensive Organic Synthesis, Volume 1: Additions to C&mdash;X π-Bonds, Part 1|pages=49–75|chapter=Carbanions of Alkali and Alkaline Earth Cations: (ii) Selectivity of Carbonyl Addition Reactions|editor1-last=Trost|editor1-first=B. M.|editor2-last=Fleming|editor2-first=I.|isbn=978-0-08-052349-1|editor1-link=Barry Trost|editor2-link=Ian Fleming (chemist)|publisher= [[Elsevier Science]]|doi= 10.1016/B978-0-08-052349-1.00002-0}}</ref><ref>{{cite web|publisher=Portland Community College|title=The Grignard Reaction. Preparation of Benzoic Acid|url=http://spot.pcc.edu/~chandy/242/PreparationofBenzoicAcid.pdf|access-date=2015-03-12|url-status=dead|archive-url=https://web.archive.org/web/20150226115836/http://spot.pcc.edu/~chandy/242/PreparationofBenzoicAcid.pdf|archive-date=26 February 2015}}></ref><ref>{{cite web|publisher=University of Wisconsin-Madison|title=Experiment 9: Synthesis of Benzoic Acid via Carbonylation of a Grignard Reagent|url=http://www.chem.wisc.edu/courses/342/Fall2004/Experiment_9.pdf|access-date=12 March 2015|archive-url=https://web.archive.org/web/20150923202908/http://www.chem.wisc.edu/courses/342/Fall2004/Experiment_9.pdf|archive-date=23 September 2015|url-status=dead}}</ref><ref>{{cite web|publisher=Towson University|title=Experiment 3: Preparation of Benzoic Acid|url=http://pages.towson.edu/jdiscord/WWW/332_Lab_Info/332LabsIRPMR/Expt3Grignard.pdf|access-date=2015-03-12|url-status=dead|archive-url=https://web.archive.org/web/20150413011353/http://pages.towson.edu/jdiscord/www/332_lab_info/332labsirpmr/expt3grignard.pdf |archive-date=13 April 2015 |df=dmy-all }}></ref>

==== Oxidation of benzyl compounds====

[[Benzyl alcohol]]<ref>{{Cite journal|last1=Santonastaso|first1=Marco|last2=Freakley|first2=Simon J.|last3=Miedziak|first3=Peter J.|last4=Brett|first4=Gemma L.|last5=Edwards|first5=Jennifer K.|last6=Hutchings|first6=Graham J.|date=2014-11-21|title=Oxidation of Benzyl Alcohol using in Situ Generated Hydrogen Peroxide|journal=Organic Process Research & Development|volume=18|issue=11|pages=1455–1460|doi=10.1021/op500195e|issn=1083-6160}}</ref> 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&nbsp;°C:<ref name=Ull>{{Ullmann|doi=10.1002/14356007.a03_555|chapter=Benzoic Acid and Derivatives|year=2000|last1=Maki|first1=Takao|last2=Takeda|first2=Kazuo|isbn=978-3527306732}}.</ref>

:<chem>C6H5CO2H + 1/2 O2 -> C6H5OH + CO2</chem>

The temperature required can be lowered to 200&nbsp;°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 [[plasticizer]]s, such as the glycol-, diethyleneglycol-, and triethyleneglycol esters, are obtained by [[transesterification]] of [[methyl benzoate]] with the corresponding [[diol]].<ref name=Ull/> These plasticizers, which are used similarly to those derived from [[terephthalic acid]] ester, represent alternatives to [[phthalate]]s.<ref name=Ull/>

=== Precursor to sodium benzoate and related preservatives ===

Benzoic acid and its salts are used as [[food preservative]]s, represented by the [[E numbers]] [[E210]], [[sodium benzoate|E211]], [[potassium benzoate|E212]], and [[calcium benzoate|E213]]. Benzoic acid inhibits the growth of [[Mold (fungus)|mold]], [[yeast]]<ref>{{cite journal | author=A D Warth | title= Mechanism of action of benzoic acid on Zygosaccharomyces bailii: effects on glycolytic metabolite levels, energy production, and intracellular pH | journal=Appl Environ Microbiol | date=1 December 1991| volume=57|pages=3410–4 | pmid= 1785916 | issue=12 | doi= 10.1128/AEM.57.12.3410-3414.1991 | pmc=183988 | bibcode= 1991ApEnM..57.3410W }}</ref> 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 [[Fermentation (biochemistry)|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.<ref>{{cite journal |vauthors=Pastrorova I, de Koster CG, Boom JJ | title= Analytic Study of Free and Ester Bound Benzoic and Cinnamic Acids of Gum Benzoin Resins by GC-MS HPLC-frit FAB-MS | journal=Phytochem Anal | year=1997 | volume=8|pages=63–73 |doi= 10.1002/(SICI)1099-1565(199703)8:2<63::AID-PCA337>3.0.CO;2-Y | issue=2 }}</ref> Benzoic acid, benzoates

and their derivatives are used as [[preservative]]s for acidic foods and beverages such as [[citrus fruit]] [[fruit juice|juice]]s ([[citric acid]]), sparkling drinks ([[carbon dioxide]]), [[soft drinks]] ([[phosphoric acid]]), [[Pickling|pickles]] ([[vinegar]]) and other acidified foods.

Typical [[Concentration|concentrations]] of 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.<ref>[http://www.codexalimentarius.net/gsfaonline/groups/details.html?id=162 GSFA Online Food Additive Group Details: Benzoates (2006)] {{webarchive |url=https://web.archive.org/web/20070926233935/http://www.codexalimentarius.net/gsfaonline/groups/details.html?id=162 |date=26 September 2007 }}</ref><ref>[http://europa.eu.int/eur-lex/en/consleg/pdf/1995/en_1995L0002_do_001.pdf EUROPEAN PARLIAMENT AND COUNCIL DIRECTIVE No 95/2/EC of 20 February 1995 on food additives other than colours and sweeteners (Consleg-versions do not contain the latest changes in a law)] {{webarchive |url=https://web.archive.org/web/20030419083114/http://europa.eu.int/eur-lex/en/consleg/pdf/1995/en_1995L0002_do_001.pdf |date=19 April 2003 }}</ref>

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]].<ref>{{cite web |url=http://www.bfr.bund.de/cm/245/indications_of_the_possible_formation_of_benzene_from_benzoic_acid_in_foods.pdf |archive-url=https://web.archive.org/web/20060426194742/http://www.bfr.bund.de/cm/245/indications_of_the_possible_formation_of_benzene_from_benzoic_acid_in_foods.pdf |archive-date=2006-04-26 |url-status=live |title=Indications of the possible formation of benzene from benzoic acid in foods, BfR Expert Opinion No. 013/2006 |publisher = German Federal Institute for Risk Assessment |date=1 December 2005 |access-date=30 March 2022}}</ref>

{{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 [[ringworm]] and [[athlete's foot]].<ref>{{cite web |url=http://www.medipharmalimited.com/whitfield_ointment.asp |title=Whitfield Ointment |access-date=15 October 2007 |archive-url=https://web.archive.org/web/20071009152212/http://www.medipharmalimited.com/whitfield_ointment.asp |archive-date=9 October 2007 |url-status=dead }}</ref><ref>{{cite book | title = Wilson and Gisvold's Textbook of Organic Medicinal and Pharmaceutical | url = https://archive.org/details/wilsongisvoldste00bloc_128 | url-access = limited |author1=Charles Owens Wilson |author2=Ole Gisvold |author3=John H. Block | year = 2004 | publisher = Lippincott Williams & Wilkins | isbn = 978-0-7817-3481-3 | pages = [https://archive.org/details/wilsongisvoldste00bloc_128/page/n245 234]}}</ref> As the principal component of [[benzoin (resin)|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 [[antiseptic]]s and inhalant [[decongestant]]s.

Benzoic acid was used as an [[expectorant]], [[analgesic]], and [[antiseptic]] in the early 20th century.<ref>{{Cite journal|title=Troches of Benzoic Acid|url= https://books.google.com/books?id=cs3mAAAAMAAJ&pg=PA25|journal=Practical Druggist and Pharmaceutical Review of Reviews|last1=Lillard|first1=Benjamin|year=1919}}</ref>

===Niche and laboratory uses===

In teaching laboratories, benzoic acid is a common standard for calibrating a [[bomb calorimeter]].<ref>[http://www.uwlax.edu/faculty/loh/pdf_files/chm313_pdf/Manual_current/chm313_Expt2_bomb.pdf Experiment 2: Using Bomb Calorimetry to Determine the Resonance Energy of Benzene] {{webarchive|url=https://web.archive.org/web/20120309020205/http://www.uwlax.edu/faculty/loh/pdf_files/chm313_pdf/Manual_current/chm313_Expt2_bomb.pdf |date=9 March 2012 }}</ref>

== 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 [[apple]]s 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 [[muskox]]en (''Ovibos moschatus'') or Asian bull elephants (''[[Elephas maximus]]'').<ref name = "concise" /> [[Benzoin (resin)|Gum benzoin]] contains up to 20% of benzoic acid and 40% benzoic acid esters.<ref>{{cite journal|vauthors=Tomokuni K, Ogata M | title=Direct Colorimetric Determination of Hippuric Acid in Urine| journal=Clin Chem | year=1972 | pages=349–351| volume=18| pmid= 5012256| issue= 4| doi=10.1093/clinchem/18.4.349| doi-access=free}}</ref>

In terms of its biosynthesis, benzoate is produced in plants from cinnamic acid.<ref name=Vogt>{{cite journal|journal=Molecular Plant|volume=3|year=2010|pages=2–20|doi=10.1093/mp/ssp106|pmid=20035037|title=Phenylpropanoid Biosynthesis|author=Vogt, T.|doi-access=free}}</ref> A pathway has been identified from [[phenol]] via [[4-hydroxybenzoate]].<ref name=Juteau>{{cite journal|first=Pierre|last=Juteau|author2=Valérie Côté|author3=Marie-France Duckett|author4=Réjean Beaudet|author5=François Lépine|author6=Richard Villemur|author7=Jean-Guy Bisaillon|title=Cryptanaerobacter phenolicus gen. nov., sp. nov., an anaerobe that transforms phenol into benzoate via 4-hydroxybenzoate|journal=International Journal of Systematic and Evolutionary Microbiology|volume=55|issue=1|pages=245–250|date=January 2005|doi=10.1099/ijs.0.02914-0|pmid=15653882|doi-access=free}}</ref>

== Reactions ==

Reactions of benzoic acid can occur at either the [[aromaticity|aromatic ring]] or at the [[carboxyl group]].

===Aromatic ring===

:[[Image:Benzoic acid-chemical-reaction-1.svg|center|benzoic acid aromatic ring reactions]]

[[Electrophilic aromatic substitution]] reaction will take place mainly in 3-position due to the [[deactivating group|electron-withdrawing]] [[carboxylic group]]; i.e. benzoic acid is [[electrophilic aromatic substitution#Meta directors|''meta'' directing]].<ref>{{OrgSynth | author=Brewster, R. Q. |author2=Williams, B. |author3=Phillips, R. |title=3,5-Dinitrobenzoic Acid| | collvol = 3 | collvolpages = 337 | year= 1955 | prep = cv3p0337}}</ref>

=== Carboxyl group ===

Reactions typical for [[carboxylic acid]]s apply also to benzoic acid.<ref name=Ull/>

* Benzoate [[ester]]s are the product of the acid catalysed reaction with [[Alcohol (chemistry)|alcohol]]s.

* Benzoic acid [[amide]]s are usually prepared from [[benzoyl chloride]].

* Dehydration to [[benzoic anhydride]] is induced with [[acetic anhydride]] or [[phosphorus pentoxide]].

* Highly reactive acid derivatives such as [[Acyl halide|acid halides]] are easily obtained by mixing with [[halogenation]] agents like [[phosphorus chlorides]] or [[thionyl chloride]].

* [[Orthoester]]s 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]], [[lithium aluminium hydride|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.

:[[Image:Benzoic acid-chemical-reaction-2.svg|center|400px|benzoic acid group reactions]]

==Safety and mammalian metabolism{{anchor|Metabolism}}==<!-- This section is linked from [[Acetate CoA-transferase]] -->

It is excreted as [[hippuric acid]].<ref>{{cite journal | author= Cosmetic Ingredient Review Expert Panel Bindu Nair | title= Final Report on the Safety Assessment of Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate| journal=Int J Tox | year=2001 | volume= 20 | issue=Suppl. 3 | pages=23–50 | doi= 10.1080/10915810152630729 | pmid= 11766131| s2cid= 13639993}}</ref> Benzoic acid is metabolized by [[butyrate-CoA ligase]] into an intermediate product, [[benzoyl-CoA]],<ref name="Benzoic1">{{cite web| title=butyrate-CoA ligase| url=http://www.brenda-enzymes.org/php/result_flat.php4?ecno=6.2.1.2&Suchword=&organism%5B%5D=Homo+sapiens&show_tm=0| website=BRENDA| publisher=Technische Universität Braunschweig.| access-date=7 May 2014}} Substrate/Product</ref> which is then metabolized by [[glycine N-acyltransferase|glycine ''N''-acyltransferase]] into hippuric acid.<ref name="Benzoic2">{{cite web| title=glycine N-acyltransferase|url=http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.13&Suchword=&organism%5B%5D=Homo+sapiens&show_tm=0|website=BRENDA|publisher=Technische Universität Braunschweig.|access-date=7 May 2014}} Substrate/Product</ref> Humans metabolize [[toluene]] which is also excreted as hippuric acid.<ref>{{cite journal |vauthors=Krebs HA, Wiggins D, Stubbs M | title= Studies on the mechanism of the antifungal action of benzoate | journal= Biochem J | year=1983 | volume=214 | pages=657–663| pmid=6226283 | issue=3 | pmc=1152300 | doi= 10.1042/bj2140657 }}</ref>

For humans, the [[World Health Organization]]'s [[International Programme on Chemical Safety]] (IPCS) suggests a provisional tolerable intake would be 5&nbsp;mg/kg body weight per day.<ref name="concise">{{cite web|url=http://www.inchem.org/documents/cicads/cicads/cicad26.htm|title= Concise International Chemical Assessment Document 26: BENZOIC ACID AND SODIUM BENZOATE}}</ref> [[Cat]]s have a significantly lower tolerance against benzoic acid and its [[Salt (chemistry)|salts]] than [[rat]]s and [[mouse|mice]]. Lethal dose for cats can be as low as 300&nbsp;mg/kg body weight.<ref>{{cite journal| doi= 10.1136/vr.90.3.53|vauthors=Bedford PG, Clarke EG |title=Experimental benzoic acid poisoning in the cat|journal=Vet Rec |year=1972|pages=53–58|volume=90 |pmid = 4672555| issue= 3|s2cid=2553612 }}</ref> The oral {{LD50}} for rats is 3040&nbsp;mg/kg, for mice it is 1940–2263&nbsp;mg/kg.<ref name="concise" />

In [[Taipei]], Taiwan, a city health survey in 2010 found that 30% of dried and pickled food products had benzoic acid.<ref>{{cite news|first=Jian|last= Chen|author2=Y.L. Kao|url=http://www.chinapost.com.tw/taiwan/national/national-news/2010/01/18/241326/Nearly-30.htm |title=Nearly 30% dried, pickled foods fail safety inspections|newspaper=[[The China Post]]| date=18 January 2010}}</ref>

== See also ==

* {{Annotated link|Niacin}}

== References ==

{{reflist|30em}}

== External links ==

{{Commons category|Benzoic acid}}

*{{ICSC|0103|01}}

*{{SIDS|name=Benzoic Acid| id= BENZOATES}}

* [https://archive.today/20121209064921/http://www.chemicalland21.com/arokorhi/industrialchem/organic/BENZOIC%20ACID.htm ChemicalLand]

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[[Category:Benzoic acids| ]]

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[[Category:Phenyl compounds]]

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