O-Cresol

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o-Cresol
Kekule, skeletal formula of o-cresol with some implicit hydrogens shown O-Kresol.svg
Kekulé, skeletal formula of o-cresol with some implicit hydrogens shown
Spacefill model of o-cresol Ortho-cresol-3D-vdW.png
Spacefill model of o-cresol
Names
Preferred IUPAC name
2-Methylphenol
Systematic IUPAC name
2-Methylbenzenol
Other names
2-Cresol
o-Cresol
ortho-Cresol
ortho-Toluenol
ortho-Benzol
2-Hydroxytoluene
o-Cresylic acid
1-Hydroxy-2-methylbenzene
Identifiers
3D model (JSmol)
3DMet
506917
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.002.204 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 202-423-8
101619
KEGG
MeSH 2-Cresol
PubChem CID
RTECS number
  • GO6300000
UNII
UN number 2076, 3455
  • InChI=1S/C7H8O/c1-6-4-2-3-5-7(6)8/h2-5,8H,1H3 Yes check.svgY
    Key: QWVGKYWNOKOFNN-UHFFFAOYSA-N X mark.svgN
  • Cc1ccccc1O
Properties
C7H8O
Molar mass 108.140 g·mol−1
AppearanceColorless to white crystals
Odor sweet, phenolic odor
Density 1.0465 g cm−3
Melting point 31 °C; 88 °F; 304 K
Boiling point 191 °C; 376 °F; 464 K
31 g dm−3 (at 40 °C)
Solubility soluble in chloroform, ether, CCl4
Solubility in ethanol Miscible (at 30 °C)
Solubility in diethyl ether Miscible (at 30 °C)
log P 1.962
Vapor pressure 40 Pa (at 20 °C)
Acidity (pKa)10.316
Basicity (pKb)3.681
−72.9×10−6 cm3/mol
1.5353
Viscosity 35.06 cP (at 45 °C)
Thermochemistry
154.56 J K−1 mol−1
Std molar
entropy
(S298)
165.44 J K−1 mol−1
−204.3 kJ mol−1
−3.6936 MJ mol−1
Hazards
GHS labelling:
GHS-pictogram-acid.svg GHS-pictogram-skull.svg
Danger
H301, H311, H314
P260, P264, P270, P280, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P322, P330, P361, P363, P405, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
2
0
Flash point 81 °C (178 °F; 354 K)
598.9 °C (1,110.0 °F; 872.0 K)
Explosive limits 1.4%–? (148 °C) [1]
Lethal dose or concentration (LD, LC):
1350 mg/kg (rat, oral)
121 mg/kg (rat, oral)
344 mg/kg (mouse, oral) [2]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 5 ppm (22 mg/m3) [skin] [1]
REL (Recommended)
TWA 2.3 ppm (10 mg/m3) [1]
IDLH (Immediate danger)
250 ppm [1]
Safety data sheet (SDS) External MSDS
Related compounds
Related phenols
Cresols:
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

ortho-Cresol (IUPAC name: 2-methylphenol, also known as 2-hydroxytoluene or ortho-Toluenol) 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 and is an isomer of p-cresol and m-cresol. [3]

Contents

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. [4]

o-Cresol is a constituent of tobacco smoke. [5]

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:

C6H5OH + CH3OH → CH3C6H4OH + H2O

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. [3]

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. [3]

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 LD50 for oral ingestion by mice is 344 mg/kg. [3]

Related Research Articles

<span class="mw-page-title-main">Aromatic compound</span> Compound containing rings with delocalized pi electrons

Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The word "aromatic" originates from the past grouping of molecules based on smell, before their general chemical properties were understood. The current definition of aromatic compounds does not have any relation with their smell.

<span class="mw-page-title-main">Phenol</span> Organic compound (C6H5OH)

Phenol, or Benzenol, is an aromatic organic compound with the molecular formula C6H5OH. It is a white crystalline solid that is volatile. The molecule consists of a phenyl group bonded to a hydroxy group. Mildly acidic, it requires careful handling because it can cause chemical burns.

<span class="mw-page-title-main">Creosote</span> Tar distillation byproduct used as wood preservative

Creosote is a category of carbonaceous chemicals formed by the distillation of various tars and pyrolysis of plant-derived material, such as wood, or fossil fuel. They are typically used as preservatives or antiseptics.

<span class="mw-page-title-main">Butanone</span> Chemical compound

Butanone, also known as methyl ethyl ketone (MEK) or ethyl methyl ketone, is an organic compound with the formula CH3C(O)CH2CH3. This colorless liquid ketone has a sharp, sweet odor reminiscent of acetone. It is produced industrially on a large scale, but occurs in nature only in trace amounts. It is partially soluble in water, and is commonly used as an industrial solvent. It is an isomer of another solvent, tetrahydrofuran.

Cresols are a group of aromatic organic compounds. They are widely-occurring phenols which may be either natural or manufactured. They are also categorized as methyl phenols. Cresols commonly occur as either solids or liquids because their melting points are generally close to room temperature. Like other types of phenols, they are slowly oxidized by exposure to air, and the resulting impurities often give the samples a yellow to brownish red tint. Cresols have an odor characteristic to that of other simple phenols, reminiscent to some of a "coal tar" smell. The name "cresol" is an adduct of phenol and their traditional source, creosote.

<span class="mw-page-title-main">Phthalic anhydride</span> Chemical compound

Phthalic anhydride is the organic compound with the formula C6H4(CO)2O. It is the anhydride of phthalic acid. Phthalic anhydride is a principal commercial form of phthalic acid. It was the first anhydride of a dicarboxylic acid to be used commercially. This white solid is an important industrial chemical, especially for the large-scale production of plasticizers for plastics. In 2000, the worldwide production volume was estimated to be about 3 million tonnes per year.

In organic chemistry, dihydroxybenzenes (benzenediols) are organic compounds in which two hydroxyl groups are substituted onto a benzene ring. These aromatic compounds are classed as phenols. There are three structural isomers: 1,2-dihydroxybenzene is commonly known as catechol, 1,3-dihydroxybenzene is commonly known as resorcinol, and 1,4-dihydroxybenzene is commonly known as hydroquinone.

<span class="mw-page-title-main">Hydroquinone</span> Chemical compound

Hydroquinone, also known as benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, a derivative of benzene, having the chemical formula C6H4(OH)2. It has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid. Substituted derivatives of this parent compound are also referred to as hydroquinones. The name "hydroquinone" was coined by Friedrich Wöhler in 1843.

<span class="mw-page-title-main">Phosphorus trichloride</span> Chemical compound

Phosphorus trichloride is an inorganic compound with the chemical formula PCl3. A colorless liquid when pure, it is an important industrial chemical, being used for the manufacture of phosphites and other organophosphorus compounds. It is toxic and reacts readily with water to release hydrogen chloride.

<i>tert</i>-Butyl alcohol Chemical compound

tert-Butyl alcohol is the simplest tertiary alcohol, with a formula of (CH3)3COH (sometimes represented as t-BuOH). Its isomers are 1-butanol, isobutanol, and butan-2-ol. tert-Butyl alcohol is a colorless solid, which melts near room temperature and has a camphor-like odor. It is miscible with water, ethanol and diethyl ether.

<i>p</i>-Cresol Chemical compound

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 and is an isomer of o-cresol and m-cresol.

<i>m</i>-Cresol Chemical compound

meta-Cresol, also 3-methylphenol, is an organic compound with the formula CH3C6H4(OH). It is a colourless, viscous liquid that is used as an intermediate in the production of other chemicals. It is a derivative of phenol and is an isomer of p-cresol and o-cresol.

Xylenols are organic compounds with the formula (CH3)2C6H3OH. They are volatile colorless solids or oily liquids. They are derivatives of phenol with two methyl groups at various positions relative to the hydroxyl group. Six isomers exist, of which 2,6-xylenol with both methyl groups in an ortho position with respect to the hydroxyl group is the most important. The name xylenol is a portmanteau of the words xylene and phenol.

<span class="mw-page-title-main">2,6-Xylenol</span> Chemical compound

2,6-Xylenol is a chemical compound which is one of the six isomers of xylenol. It is also commonly known as 2,6-dimethylphenol (DMP). It is a colorless solid.

2,4-Dimethyl-6-<i>tert</i>-butylphenol Chemical compound

2,4-Dimethyl-6-tert-butylphenol is the organic compound with the formula Me2(tert-Bu)C6H2OH (Me = methyl, tert-Bu = tertiary butyl). It is a colorless oil that is classified as an alkylated phenol.

<span class="mw-page-title-main">Tricresyl phosphate</span> Chemical compound

Tricresyl phosphate (TCP), is a mixture of three isomeric organophosphate compounds most notably used as a flame retardant. Other uses include as a plasticizer in manufacturing for lacquers and varnishes and vinyl plastics and as an antiwear additive in lubricants. Pure tricresyl phosphate is a colourless, viscous liquid, although commercial samples are typically yellow. It is virtually insoluble in water, but easily soluble in organic solvents like toluene, hexane, and diethylether among others. It was synthesized by Alexander Williamson in 1854 upon reacting phosphorus pentachloride with cresol, though today's manufacturers can prepare TCP by mixing cresol with phosphorus oxychloride or phosphoric acid as well. TCP, especially the all-ortho isomer, is the causative agent in a number of acute poisonings. Its chronic toxicity is also of concern. The ortho-isomer is rarely used on its own outside of laboratory studies that require isomeric purity, due to its extremely toxic nature, and is generally excluded from commercial products where TCP is involved.

<span class="mw-page-title-main">Benzene</span> Hydrocarbon compound consisting of a 6-sided ring

Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon.

Dinitro-<i>ortho</i>-cresol Chemical compound

Dinitro-ortho-cresol (DNOC) is an organic compound with the structural formula CH3C6H2(NO2)2OH. It is a yellow solid that is only slightly soluble in water. DNOC and some related derivatives have been used as herbicides.

<span class="mw-page-title-main">EPN (insecticide)</span> Chemical compound

EPN is an insecticide of the phosphonothioate class. It is used against pests such as European corn borer, rice stem borer, bollworm, tobacco budworm, and boll weevil.

2-Nitrotoluene or ortho-nitrotoluene is an organic compound with the formula CH3C6H4NO2. It is pale yellow liquid that crystallizes in two forms, called α (−9.27 °C) and β (−3.17 °C). It is mainly a precursor to o-toluidine, which is an intermediate in the production of various dyes.

References

  1. 1 2 3 4 NIOSH Pocket Guide to Chemical Hazards. "#0154". National Institute for Occupational Safety and Health (NIOSH).
  2. "Cresol (o, m, p isomers)". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. 1 2 3 4 Helmut Fiegein "Cresols and Xylenols" in Ullmann's Encyclopedia of Industrial Chemistry" 2007; Wiley-VCH, Weinheim. doi : 10.1002/14356007.a08_025
  4. The Beaver: Its Life and Impact. Dietland Muller-Schwarze, 2003, page 43 (book at google books)
  5. Talhout, Reinskje; Schulz, Thomas; Florek, Ewa; Van Benthem, Jan; Wester, Piet; Opperhuizen, Antoon (2011). "Hazardous Compounds in Tobacco Smoke". International Journal of Environmental Research and Public Health. 8 (12): 613–628. doi: 10.3390/ijerph8020613 . ISSN   1660-4601. PMC   3084482 . PMID   21556207.