{{DISPLAYTITLE:''o''-Cresol}} {{Chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 416907599 | Name = ''o''-Cresol | ImageFileL1 = O-Kresol.svg | ImageClassL1 = skin-invert-image | ImageFileL1_Ref = {{chemboximage|correct|??}} | ImageNameL1 = Kekulé, skeletal formula of ''o''-cresol with some implicit hydrogens shown | ImageFileR1 = Ortho-cresol-3D-vdW.png | ImageClassR1 = bg-transparent | 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 cm<sup>−3</sup> | Solubility = 31 g dm<sup>−3</sup> (at 40 °C) | Solvent1 = ethanol | Solubility1 = Miscible (at 30 °C) | Solvent2 = diethyl ether | Solubility2 = Miscible (at 30 °C) | SolubleOther = soluble in chloroform, ether, CCl<sub>4</sub> | MeltingPtK = 304 | BoilingPtK = 464 | RefractIndex = 1.5353 | LogP = 1.962 | VaporPressure = 40 Pa (at 20 °C) | pKa = 10.316 | pKb = 3.681 | Viscosity = 35.06 cP (at 45 °C) | MagSus = {{val|-72.9e-6|u=cm<sup>3</sup>/mol}} }} |Section3={{Chembox Thermochemistry | DeltaHf = −204.3 kJ mol<sup>−1</sup> | DeltaHc = −3.6936 MJ mol<sup>−1</sup> | Entropy = 165.44 J K<sup>−1</sup> mol<sup>−1</sup> | HeatCapacity = 154.56 J K<sup>−1</sup> 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 °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 = phenols | OtherFunction = Cresols: * ''m''-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 and ''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 from coal. A similar source material is petroleum residues. These residue contains a few percent by weight of phenol and isomeric cresols. 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. Chlorination and etherification gives members of commercially important herbicides, such as 2-methyl-4-chlorophenoxyacetic acid (MCPA). Nitration gives dinitrocresol, a popular herbicide. Kolbe–Schmitt carboxylation gives ''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 skin at very high levels, they can be harmful. Breathing high levels of cresols for a short time results in irritation of the 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 LD<sub>50</sub> for oral ingestion by mice is 344 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