View source for O-Cresol

{{DISPLAYTITLE:''o''-Cresol}}
{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 416907599
| Name = ''o''-Cresol
| ImageFileL1 = O-Kresol.svg
| ImageFileL1_Ref = {{chemboximage|correct|??}}
| ImageNameL1 = Kekulé, skeletal formula of ''o''-cresol with some implicit hydrogens shown
| ImageFileR1 = Ortho-cresol-3D-vdW.png
| ImageFileR1_Ref = {{chemboximage|correct|??}}
| ImageNameR1 = Spacefill model of ''o''-cresol
| PIN = 2-Methylphenol
| SystematicName = 2-Methylbenzenol
| OtherNames = 2-Cresol<br />''o''-Cresol<br />''ortho''-Cresol<br />''ortho''-Toluenol<br />''ortho''-Benzol<br />2-Hydroxytoluene<br />''o''-Cresylic acid<br />1-Hydroxy-2-methylbenzene
|Section1={{Chembox Identifiers
| CASNo = 95-48-7
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem = 335
| EINECS = 202-423-8
| UNNumber = 2076, 3455
| KEGG = C01542
| KEGG_Ref = {{keggcite|correct|kegg}}
| MeSHName = 2-Cresol
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 28054
| ChEMBL = 46931
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| RTECS = GO6300000
| Beilstein = 506917
| Gmelin = 101619
| 3DMet = B00313
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = YW84DH5I7U
| SMILES = Cc1ccccc1O
| StdInChI = 1S/C7H8O/c1-6-4-2-3-5-7(6)8/h2-5,8H,1H3
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = QWVGKYWNOKOFNN-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 13835772
}}
|Section2={{Chembox Properties
| Appearance = Colorless to white crystals
| Odor = sweet, phenolic odor
| C=7 | H=8 | O=1
| Density = 1.0465 g&nbsp;cm<sup>−3</sup>
| Solubility = 31 g&nbsp;dm<sup>−3</sup> (at 40&nbsp;°C)
| Solvent1 = ethanol
| Solubility1 = Miscible (at 30&nbsp;°C)
| Solvent2 = diethyl ether
| Solubility2 = Miscible (at 30&nbsp;°C)
| SolubleOther = soluble in [[chloroform]], [[diethyl ether|ether]], [[carbon tetrachloride|CCl<sub>4</sub>]]
| MeltingPtK = 304
| BoilingPtK = 464
| RefractIndex = 1.5353
| LogP = 1.962
| VaporPressure = 40 Pa (at 20&nbsp;°C)
| pKa = 10.316
| pKb = 3.681
| Viscosity = 35.06 cP (at 45&nbsp;°C)
| MagSus = {{val|-72.9e-6|u=cm<sup>3</sup>/mol}}
}}
|Section3={{Chembox Thermochemistry
| DeltaHf = −204.3 kJ&nbsp;mol<sup>−1</sup>
| DeltaHc = −3.6936 MJ&nbsp;mol<sup>−1</sup>
| Entropy = 165.44 J&nbsp;K<sup>−1</sup>&nbsp;mol<sup>−1</sup>
| HeatCapacity = 154.56 J&nbsp;K<sup>−1</sup>&nbsp;mol<sup>−1</sup>
}}
|Section4={{Chembox Hazards
| ExternalSDS = [https://fscimage.fishersci.com/msds/95810.htm External MSDS]
| GHSPictograms = {{GHS05}}{{GHS06}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|301|311|314}}
| PPhrases = {{P-phrases|260|264|270|280|301+310|301+330+331|302+352|303+361+353|304+340|305+351+338|310|312|321|322|330|361|363|405|501}}
| NFPA-H = 3
| NFPA-F = 2
| NFPA-R = 0
| FlashPtC = 81
| AutoignitionPtC = 598.9
| LD50 = 1350 mg/kg (rat, oral)<br />121 mg/kg (rat, oral)<br />344 mg/kg (mouse, oral)<ref>{{IDLH|cresol|Cresol (o, m, p isomers)}}</ref>
| PEL = TWA 5 ppm (22 mg/m<sup>3</sup>) [skin]<ref name=PGCH>{{PGCH|0154}}</ref>
| ExploLimits = 1.4%–? (148&nbsp;°C)<ref name=PGCH/>
| IDLH = 250 ppm<ref name=PGCH/>
| REL = TWA 2.3 ppm (10 mg/m<sup>3</sup>)<ref name=PGCH/>
}}
|Section5={{Chembox Related
| OtherFunction_label = [[phenol]]s
| OtherFunction = [[Cresols]]:
* [[m-Cresol|''m''-cresol]]
* [[p-cresol|''p''-cresol]]<br />[[benzyl alcohol]], [[phenol]]
}}
}}
'''''ortho''-Cresol''' ([[IUPAC]] name: '''2-methylphenol''', also known as '''2-hydroxytoluene''' or '''''ortho''-Toluenol''') is an [[organic compound]] with the formula CH<sub>3</sub>C<sub>6</sub>H<sub>4</sub>(OH). It is a colourless solid that is widely used intermediate in the production of other chemicals. It is a derivative of [[phenol]] and is an isomer of [[P-Cresol|''p''-cresol]] and [[M-Cresol|''m''-cresol]].<ref name=Ullmann>Helmut Fiegein "Cresols and Xylenols" in Ullmann's Encyclopedia of Industrial Chemistry" 2007; Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a08_025}}</ref>
== Natural occurrences ==
''o''-Cresol is one of the chemical compounds found in [[castoreum]]. This compound is gathered from the beaver's castor glands and found in the white cedar consumed by the [[beaver]].<ref>The Beaver: Its Life and Impact. Dietland Muller-Schwarze, 2003, page 43 ([https://books.google.com/books?id=HZ5WjXB5Pr8C&dq=Castoreum+beekeeping&pg=PA43 book at google books])</ref>
''o''-Cresol is a constituent of [[tobacco smoke]].<ref>{{cite journal|last1=Talhout|first1=Reinskje|last2=Schulz|first2=Thomas|last3=Florek|first3=Ewa|last4=Van Benthem|first4=Jan|last5=Wester|first5=Piet|last6=Opperhuizen|first6=Antoon|title=Hazardous Compounds in Tobacco Smoke|journal=International Journal of Environmental Research and Public Health|volume=8|issue=12|year=2011|pages=613–628|issn=1660-4601|doi=10.3390/ijerph8020613|pmid=21556207|pmc=3084482|doi-access=free}}</ref>
== Production ==
Together with many other compounds, ''o''-cresol is traditionally extracted from [[coal tar]], the volatile materials obtained in the production of [[Coke (fuel)|coke]] from [[coal]]. A similar source material is petroleum residues.  These residue contains a few percent by weight of [[phenol]] and isomeric [[cresol]]s. In addition to the materials derived from these natural sources, about two thirds of the Western world's supply is produced by [[methylation]] of phenol using [[methanol]]. The [[alkylation]] is catalysed by metal oxides:
:C<sub>6</sub>H<sub>5</sub>OH + CH<sub>3</sub>OH → CH<sub>3</sub>C<sub>6</sub>H<sub>4</sub>OH + H<sub>2</sub>O
Over-methylation gives [[xylenol]]. Many other production methods have been examined, including oxidative decarboxylation of [[salicylic acid]], oxygenation of [[toluene]], and hydrolysis of [[2-chlorotoluene]].<ref name=Ullmann/>
== Applications ==
''o''-Cresol is mainly used as a precursor to other compounds. [[halogenation|Chlorination]] and [[etherification]] gives members of commercially important [[herbicide]]s, such as [[2-methyl-4-chlorophenoxyacetic acid]] (MCPA). Nitration gives [[dinitrocresol]], a popular herbicide. [[Kolbe–Schmitt reaction|Kolbe–Schmitt carboxylation]] gives [[o-cresotinic acid|''o''-cresotinic acid]], a pharmaceutical intermediate. [[Carvacrol]], essence of oregano, is derived by alkylation of ''o''-cresol with [[propene]]. The muscle relaxant [[mephenesin]] is an ether derived from ''o''-cresol.<ref name=Ullmann/>
== Health effects ==
Most exposures to cresols are at very low levels that are not harmful although, like phenols, cresols are skin irritants. When cresols are inhaled, ingested, or applied to the [[human skin|skin]] at very high levels, they can be harmful. Breathing high levels of cresols for a short time results in irritation of the [[Human nose|nose]] and throat. Aside from these effects, very little is known about the effects of breathing cresols at lower levels over longer times. The acute [[LD50|LD<sub>50</sub>]] for oral ingestion by mice is 344&nbsp;mg/kg.<ref name=Ullmann/>
== References ==
{{reflist}}
== External links ==
* [http://www.inchem.org/documents/icsc/icsc/eics0030.htm ''o''-CRESOL (ICSC)]
* [https://web.archive.org/web/20040529224625/http://www.syrres.com/esc/smiles_ex_notations.htm Environmental Science - SMILES Examples Notations] (accessed 22 December 2022)
* [https://www.cdc.gov/niosh/npg/npgd0154.html CDC - NIOSH Pocket Guide to Chemical Hazards]
{{DEFAULTSORT:Cresol, o-}}
[[Category:Alkylphenols]]
[[Category:Antiseptics]]
[[Category:Cresols]]
[[Category:Hazardous air pollutants]]