p-Cresol

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p-Cresol
Skeletal formula of para-cresol
3D model of p-cresol
Names
IUPAC name
4-Methylphenol
Other names
4-Hydroxytoluene, p-Hydroxytoluene, p-Methylphenol, 4-Cresol, p-Cresylic acid, 1-Hydroxy-4-methylbenzene
Identifiers
106-44-5 YesY
ChEBI CHEBI:17847 YesY
ChEMBL ChEMBL16645 YesY
ChemSpider 13839082 YesY
DrugBank DB01688 YesY
Jmol-3D images Image
KEGG C01468 YesY
RTECS number GO6475000
UNII 1MXY2UM8NV YesY
Properties
C7H8O
Molar mass 108.13
Appearance colorless prismatic crystals
Density 1.0347 g/ml
Melting point 35.5 °C (95.9 °F; 308.6 K)
Boiling point 201.8 °C (395.2 °F; 474.9 K)
2.4 g/100 ml at 40 °C
5.3 g/100 ml at 100 °C
Solubility in ethanol fully miscible
Solubility in diethyl ether fully miscible
Vapor pressure 0.11 mmHg (25°C)[1]
1.5395
Hazards
SDS External MSDS
Main hazards May be fatal if swallowed, inhaled, or absorbed through skin.
R-phrases R34 R24 R25
S-phrases S36 S37 S39 S45
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 86.1 °C (187.0 °F; 359.2 K)
Explosive limits 1.1%-?[1]
207 mg/kg (oral, rat, 1969)
1800 mg/kg (oral, rat, 1944)
344 mg/kg (oral, mouse)[1]
US health exposure limits (NIOSH):
TWA 5 ppm (22 mg/m3) [skin][1]
TWA 2.3 ppm (10 mg/m3)[1]
250 ppm[1]
Related compounds
Related phenols
o-cresol, m-cresol, phenol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
 YesY verify (what isYesY/N?)
Infobox references

para-Cresol, also 4-methylphenol, is an organic compound with the formula CH3C6H4(OH). It is a colourless solid that is widely used intermediate in the production of other chemicals. It is a derivative of phenol, an isomer of o-cresol and m-cresol.[2]

Production[edit]

Together with many other compounds, p-cresol is traditionally extracted from coal tar, the volatilized materials obtained in the roasting of coal to produce coke. This residue contains a few percent by weight of phenol and cresols. p-Cresol is currently prepared industrially mainly by a two step route beginning with the sulfonation of toluene:

CH3C6H5 + H2SO4 → CH3C6H4SO3H + H2O

Base hydrolysis of the sulfonate salt gives the sodium salt of the cresol:

CH3C6H4SO3Na + 2 NaOH → CH3C6H4OH + Na2SO3 + H2O

Other methods for the production of p-cresol include chlorination of toluene followed by hydrolysis. In the cymene-cresol process, phenol is alkylated with propylene to give p-cymene, which can be oxidatively dealkylated.[2]

Applications[edit]

p-Cresol is mainly consumed in the production of antioxidants, e.g., butylated hydroxytoluene (BHT). The monoalkylated derivatives undergo coupling to give extensive family of diphenol antioxidants. These antioxidants are valued because they are relatively low in toxicity and nonstaining.[2]

Natural occurrences[edit]

p-Cresol is a major component in pig odor.[3]

p-Cresol is a component in human sweat. It is a component of human odor attractive to female mosquitoes.[4][5]

Temporal glands secretion examination showed the presence of phenol and p-cresol during musth in male elephants.[6][7]

p-Cresol is one of the very few compounds to attract the orchid bee Euglossa cyanura and has been used to capture and study the species.[8]

References[edit]

  1. ^ a b c d e f "NIOSH Pocket Guide to Chemical Hazards #0156". National Institute for Occupational Safety and Health (NIOSH). 
  2. ^ a b c Fiege, Helmut (2000). "Cresols and Xylenols". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a08_025. ISBN 3-527-30673-0. [page needed]
  3. ^ http://www.sciam.com/article.cfm?id=why-study-pig-odor[full citation needed]
  4. ^ Hallem, Elissa A.; Nicole Fox, A.; Zwiebel, Laurence J.; Carlson, John R. (2004). "Olfaction: Mosquito receptor for human-sweat odorant". Nature 427 (6971): 212–3. Bibcode:2004Natur.427..212H. doi:10.1038/427212a. PMID 14724626. 
  5. ^ Linley, John R. (1989). "Laboratory tests of the effects of p-cresol and 4-methylcyclohexanol on oviposition by three species of Toxorhynchites mosquitoes". Medical and Veterinary Entomology 3 (4): 347–52. doi:10.1111/j.1365-2915.1989.tb00241.x. PMID 2577519. 
  6. ^ Rasmussen, L.E.L; Perrin, Thomas E (1999). "Physiological Correlates of Musth: Lipid Metabolites and Chemical Composition of Exudates". Physiology & Behavior 67 (4): 539–49. doi:10.1016/S0031-9384(99)00114-6. PMID 10549891. 
  7. ^ Ananth, Deepa. "Musth in elephants" (PDF). Zoos' Print Journal 15 (5): 259–62. 
  8. ^ Williams, Norris H.; Whitten, W. Mark (June 1983). "Orchid Floral Fragrances and Male Euglossine Bees: Methods and Advances in the Last Sesquidecade". Biological Bulletin 164 (3): 355–95. JSTOR 1541248.