Benzoic acid

{{Chembox

| Watchedfields = changed

| verifiedrevid = 476995928

| ImageFileL1 = Benzoesäure.svg

| ImageSizeL1 = 100px

| ImageNameL1 = Skeletal formula

| ImageClassL1 = skin-invert-image

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

| 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

| Abbreviations =

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 8SKN0B0MIM

| InChIKey = WPYMKLBDIGXBTP-UHFFFAOYAD

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C7H6O2/c8-7(9)6-4-2-1-3-5-6/h1-5H,(H,8,9)

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = WPYMKLBDIGXBTP-UHFFFAOYSA-N

| CASNo = 65-85-0

| CASNo_Ref = {{cascite|correct|CAS}}

| EINECS = 200-618-2

| PubChem = 243

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 238

| ChEMBL_Ref = {{ebicite|correct|EBI}}

| ChEMBL = 541

| DrugBank_Ref = {{drugbankcite|correct|drugbank}}

| DrugBank = DB03793

| SMILES = O=C(O)c1ccccc1

| InChI = 1/C7H6O2/c8-7(9)6-4-2-1-3-5-6/h1-5H,(H,8,9)

| RTECS = DG0875000

| MeSHName = benzoic+acid

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 30746

| KEGG_Ref = {{keggcite|correct|kegg}}

| KEGG = D00038

| 3DMet = B00053

| Beilstein = 636131

| Gmelin = 2946

}}

| 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 °C)
1.0749{{nbsp}}g/cm³ (130 °C)

| MeltingPtC = 122

| MeltingPt_ref =

| BoilingPtC = 250

| BoilingPt_ref ={{GESTIS|ZVG=22810}}

| Solubility = 1.7{{nbsp}}g/L (0 °C)
2.7{{nbsp}}g/L (18 °C)
3.44{{nbsp}}g/L (25 °C)
5.51{{nbsp}}g/L (40 °C)
21.45{{nbsp}}g/L (75 °C)
56.31{{nbsp}}g/L (100 °C){{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}}{{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}}

| pKa = {{ubl

| 4.202 (H₂O){{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}}

| 11.02 (DMSO){{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}}

}}

| SolubleOther = Soluble in acetone, benzene, CCl₄, CHCl₃, alcohol, ethyl ether, hexane, phenyls, liquid ammonia, acetates

| Solubility1 = 30{{nbsp}}g/100{{nnbsp}}g (−18 °C)
32.1{{nbsp}}g/100{{nnbsp}}g (−13 °C)
71.5{{nbsp}}g/100{{nnbsp}}g (23 °C)

| Solvent1 = methanol

| Solubility2 = 25.4{{nbsp}}g/100{{nnbsp}}g (−18 °C)
47.1{{nbsp}}g/100{{nnbsp}}g (15 °C)
52.4{{nbsp}}g/100{{nnbsp}}g (19.2 °C)
55.9{{nbsp}}g/100{{nnbsp}}g (23 °C)

| Solvent2 = ethanol

| Solubility3 = 54.2{{nbsp}}g/100{{nnbsp}}g (20 °C)

| Solvent3 = acetone

| Solubility4 = 4.22{{nbsp}}g/100{{nnbsp}}g (25 °C)

| Solvent4 = olive oil

| Solubility5 = 55.3{{nbsp}}g/100{{nnbsp}}g (25 °C)

| Solvent5 = 1,4-dioxane

| pKb =

| IsoelectricPt =

| LambdaMax =

| Absorbance =

| SpecRotation =

| RefractIndex = 1.5397 (20 °C)
1.504 (132 °C)

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

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

| LogP = 1.87

| MagSus = −70.28·10⁻⁶{{nbsp}}cm³/mol

}}

| Section3 = {{Chembox Structure

| CrystalStruct = Monoclinic

| Coordination =

| MolShape = Planar

| Dipole = 1.72{{nbsp}}D in dioxane

}}

| Section4 = {{Chembox Thermochemistry

| DeltaHf = −385.2{{nbsp}}kJ/mol

| DeltaHc = −3228{{nbsp}}kJ/mol

| Entropy = 167.6{{nbsp}}J/mol·K

| HeatCapacity = 146.7{{nbsp}}J/mol·K

}}

| Section7 = {{Chembox Hazards

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

| GHSPictograms = {{GHS05}}{{GHS08}}{{Sigma-Aldrich| id= w213101|name=Benzoic acid|accessdate=2014-05-23}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|318|335}}

| PPhrases = {{P-phrases|261|280|305+351+338}}

| MainHazards = Irritant

| NFPA-H = 2

| NFPA-F = 1

| NFPA-R = 0

| NFPA-S =

| FlashPtC = 121.5

| FlashPt_ref =

| AutoignitionPtC = 571

| AutoignitionPt_ref =

| ExploLimits =

| PEL =

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

}}

| Section8 = {{Chembox Related

| OtherAnions =

| OtherCations = Sodium benzoate,
Potassium benzoate

| OtherFunction = Hydroxybenzoic acids
Aminobenzoic acids,
Nitrobenzoic acids,
Phenylacetic acid

| OtherFunction_label = carboxylic acids

| OtherCompounds = Benzaldehyde,
Benzyl alcohol,
Benzoyl chloride,
Benzylamine,
Benzamide,
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 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 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{{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}} 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 ({{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).{{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 }}

Justus von Liebig and Friedrich Wöhler determined the composition of benzoic acid.{{cite journal

| author = Liebig J |author2=Wöhler F

| title = Untersuchungen über das Radikal der Benzoesäure

| journal = 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

}} These latter also investigated how hippuric acid is related to benzoic acid.

In 1875 Salkowski discovered the antifungal properties of benzoic acid, which explains the preservation of benzoate-containing cloudberry fruits.{{cite journal | author= Salkowski E| journal=Berl Klin Wochenschr| year=1875 | volume=12 | pages=297–298}}{{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 naphthenates. The process uses abundant materials, and proceeds in high yield.{{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}}

:Image:Benzoic acid-chemical-synthesis-1.svg

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%.{{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}}

== 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.{{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}} 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.{{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}}{{cite book|last=Huryn|first=D. M.|year=1991|title=Comprehensive Organic Synthesis, Volume 1: Additions to C—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}}{{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}}>{{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}}{{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 }}>

== Oxidation of benzyl compounds==

Benzyl alcohol{{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}} 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:{{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}}.

:{{chem2 | C6H5CO2H + ½ 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 food preservatives, represented by the E numbers E210, E211, E212, and E213. Benzoic acid inhibits the growth of mold, yeast{{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 }} 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.{{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 }} Benzoic acid, benzoates

and their derivatives are used as preservatives for acidic foods and beverages such as citrus fruit juices (citric acid), sparkling drinks (carbon dioxide), soft drinks (phosphoric acid), pickles (vinegar) and other acidified foods.

Typical 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.[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 }}[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 }}

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.{{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}}

= 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.{{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 }}{{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]}} 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.{{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}}

=Niche and laboratory uses=

In teaching laboratories, benzoic acid is a common standard for calibrating a bomb calorimeter.[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 }}

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.{{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}}

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

Reactions

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

=Aromatic ring=

:Image:Benzoic acid-chemical-reaction-1.svg

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.{{OrgSynth | author=Brewster, R. Q. |author2=Williams, B. |author3=Phillips, R. |title=3,5-Dinitrobenzoic Acid| | collvol = 3 | collvolpages = 337 | year= 1955 | prep = cv3p0337}}

= 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.

:Image:Benzoic acid-chemical-reaction-2.svg

==Safety and mammalian metabolism{{anchor|Metabolism}}==

It is excreted as hippuric acid.{{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}} Benzoic acid is metabolized by butyrate-CoA ligase into an intermediate product, benzoyl-CoA,{{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 which is then metabolized by glycine N-acyltransferase into hippuric acid.{{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 Humans metabolize toluene which is also excreted as hippuric acid.{{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 }}

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.{{cite web|url=http://www.inchem.org/documents/cicads/cicads/cicad26.htm|title= Concise International Chemical Assessment Document 26: BENZOIC ACID AND SODIUM BENZOATE}} 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.{{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|doi-broken-date=1 November 2024 |s2cid=2553612 }} 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.{{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}}

References

External links

{{ICSC|0103|01}}
{{SIDS|name=Benzoic Acid| id= BENZOATES}}
[https://archive.today/20121209064921/http://www.chemicalland21.com/arokorhi/industrialchem/organic/BENZOIC%20ACID.htm ChemicalLand]

Category:Excipients

Category:Phenyl compounds

Category:E-number additives