Ethylbenzene

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Ethylbenzene
Ethylbenzene-2D-skeletal.svg
Ethylbenzene-from-xtal-Mercury-3D-bs.png
Ethylbenzene-from-xtal-Mercury-3D-sf.png
Names
Preferred IUPAC name
Ethylbenzene
Other names
Ethylbenzol; Phenylethane; alpha-Methyltoluene; EB
Identifiers
3D model (JSmol)
AbbreviationsEB
1901871
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.002.591 OOjs UI icon edit-ltr-progressive.svg
KEGG
PubChem CID
RTECS number
  • DA0700000
UNII
  • InChI=1S/C8H10/c1-2-8-6-4-3-5-7-8/h3-7H,2H2,1H3 Yes check.svgY
    Key: YNQLUTRBYVCPMQ-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C8H10/c1-2-8-6-4-3-5-7-8/h3-7H,2H2,1H3
    Key: YNQLUTRBYVCPMQ-UHFFFAOYAM
  • CCc1ccccc1
Properties
C8H10
Molar mass 106.168 g·mol−1
Appearancecolorless liquid
Odor aromatic [1]
Density 0.8665 g/mL
Melting point −95 °C (−139 °F; 178 K)
Boiling point 136 °C (277 °F; 409 K)
0.015 g/100 mL (20 °C)
log P 3.27
Vapor pressure 9.998 mmHg
-77.20·10−6 cm3/mol
1.495
Viscosity 0.669 cP at 20 °C
0.58 D [2]
Thermochemistry
1.726 J/(gK)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Flammable
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg GHS-pictogram-pollu.svg
Danger
H225, H304, H320, H332, H335, H336, H351, H360, H373, H400, H411
P201, P202, P210, P233, P240, P241, P242, P243, P260, P261, P264, P271, P273, P280, P281, P301+P310, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P308+P313, P312, P314, P331, P337+P313, P370+P378, P391, P403+P233, P403+P235, P405, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
3
0
Flash point 22.22 °C (72.00 °F; 295.37 K)
430 °C (806 °F; 703 K)
Explosive limits 1–7.8%
Lethal dose or concentration (LD, LC):
5460 mg/kg
4000 ppm (rat, 4 hr) [3]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 100 ppm (435 mg/m3) [1]
REL (Recommended)
TWA 100 ppm (435 mg/m3) ST 125 ppm (545 mg/m3) [1]
IDLH (Immediate danger)
800 ppm [1]
Related compounds
styrene, toluene
Related compounds
 benzene
ethylcyclohexane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Ethylbenzene is an organic compound with the formula C6H5CH2CH3. It is a highly flammable, colorless liquid with an odor similar to that of gasoline. This monocyclic aromatic hydrocarbon is important in the petrochemical industry as a reaction intermediate in the production of styrene, the precursor to polystyrene, a common plastic material. In 2012, more than 99% of ethylbenzene produced was consumed in the production of styrene.

Occurrence and applications

Ethylbenzene occurs naturally in coal tar and petroleum. [4]

The dominant application of ethylbenzene is its role as an intermediate in the production of polystyrene. Catalytic dehydrogenation of ethylbenzene gives hydrogen and styrene:

C
6H
5CH
2CH
3 → C6H5CH=CH2 + H
2

As of May 2012, more than 99% of all the ethylbenzene produced is used for this purpose.

Ethylbenzene hydroperoxide, a reagent and radical initiator, is produced by autoxidation of ethylbenzene:

C6H5CH2CH3 + O2 → C6H5CH(O2H)CH3

Niche uses

Ethylbenzene is added to gasoline as an anti-knock agent to reduce engine knocking and increase the octane rating. Ethylbenzene is often found in other products, including pesticides, cellulose acetate, synthetic rubber, paints, and inks. [4] Used in the recovery of natural gas, ethylbenzene may be injected into the ground.

Production

Ethylbenzene is produced on a large scale by combining benzene and ethene in an acid-catalyzed chemical reaction:

C
6H
6 + C
2H
4 → C
6H
5CH
2CH
3

In 2012, more than 99% of ethylbenzene was produced in this way.[ citation needed ]

Small amounts of ethylbenzene are recovered from the mix of xylenes by superfractioning, an extension of the distillation process. [5]

In the 1980s a zeolite-based process using vapor phase alkylation offered a higher purity and yield. Then a liquid phase process was introduced using zeolite catalysts. This offers low benzene-to-ethylene ratios, reducing the size of the required equipment and lowering byproduct production. [6]

Industrial accidents

On June 3, 2014, an explosion occurred in the Dutch Moerdijk industrial area. This happened in a chemical reactor operated by Shell which overheated due to an exothermal runaway reaction between the metal oxide catalyst and ethylbenzene. [7]

Health effects

The acute toxicity of ethylbenzene is low, with an LD50 of about 4 grams per kilogram of body weight. The longer term toxicity and carcinogenicity is ambiguous. [8] Eye and throat sensitivity can occur when high level exposure to ethylbenzene in the air occurs. At higher level exposure, ethylbenzene can cause dizziness. [4] Once inside the body, ethylbenzene biodegrades to 1-phenylethanol, acetophenone, phenylglyoxylic acid, mandelic acid, benzoic acid and hippuric acid. [8] Ethylbenzene exposure can be determined by testing for the breakdown products in urine.

As of September 2007, the United States Environmental Protection Agency (EPA) determined that drinking water with a concentration of 30 parts per million (ppm) for one day or 3 ppm for ten days is not expected to have any adverse effect in children. Lifetime exposure of 0.7 ppm ethylbenzene is not expected to have any adverse effect either. The U.S. Occupational Safety and Health Administration (OSHA) limits exposure to workers to an average 100 ppm for an 8-hour workday, a 40-hour workweek. [4]

Ethylbenzene is classified as a possible carcinogen by the International Agency for Research on Cancer (IARC) however, the EPA has not determined ethylbenzene to be a carcinogen. The National Toxicology Program conducted an inhalation study in rats and mice. Exposure to ethylbenzene resulted in an increased incidence of kidney and testicular tumors in male rats, and trends of increased kidney tumors in female rats, lung tumors in male mice, and liver tumors in female mice.

As with all organic compounds, ethylbenzene vapors form an explosive mixture with air. [5] When transporting ethylbenzene, it is classified as a flammable liquid in class 3, Packing Group II. [5]

Environmental effects

Ethylbenzene is found mostly as a vapor in the air since it can easily move from water and soil. [4] A median concentration of 0.62 parts per billion (ppb) was found in urban air in 1999. [9] A study conducted in 2012 found that in country air the median concentration was found to be 0.01 ppb and indoors the median concentration was 1.0 ppb. It can also be released into the air through the burning of coal, gas, and oil. The use of ethylbenzene in the industry contributes to ethylbenzene vapor in the air. After about three days in the air with the help of sunlight, other chemicals break down ethylbenzene into chemicals that can be found in smog. [4] Since it does not readily bind to soil it can also easily move into groundwater. In surface water, it breaks down when it reacts with chemicals naturally found in water. [10] Generally, ethylbenzene is not found in drinking water, however it can be found in residential drinking water wells if the wells are near waste sites, underground fuel storage tanks that are leaking, or landfills. [4]

As of 2012, according to the EU Dangerous Substances Directive, ethylbenzene is not classified as hazardous to the environment. [5]

Ethylbenzene is a constituent of tobacco smoke. [11]

Biodegradation

Certain strains of the fungus Cladophialophora can grow on ethylbenzene. [12] The bacterium Aromatoleum aromaticum EbN1 was discovered due to its ability to grow on ethylbenzene. [13]

Related Research Articles

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

Toluene, also known as toluol, is a substituted aromatic hydrocarbon with the chemical formula C6H5CH3, often abbreviated as PhCH3, where Ph stands for phenyl group. It is a colorless, water-insoluble liquid with the odor associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) attached to a phenyl group by a single bond. As such, its systematic IUPAC name is methylbenzene. Toluene is predominantly used as an industrial feedstock and a solvent.

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

Naphthalene is an organic compound with formula C
10H
8. It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is the main ingredient of traditional mothballs.

<span class="mw-page-title-main">Xylene</span> Organic compounds with the formula (CH3)2C6H4

In organic chemistry, xylene or xylol are any of three organic compounds with the formula (CH3)2C6H4. They are derived from the substitution of two hydrogen atoms with methyl groups in a benzene ring; which hydrogens are substituted determines which of three structural isomers results. It is a colorless, flammable, slightly greasy liquid of great industrial value.

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

Styrene is an organic compound with the chemical formula C6H5CH=CH2. Its structure consists of a vinyl group as substituent on benzene. Styrene is a colorless, oily liquid, although aged samples can appear yellowish. The compound evaporates easily and has a sweet smell, although high concentrations have a less pleasant odor. Styrene is the precursor to polystyrene and several copolymers, and is typically made from benzene for this purpose. Approximately 25 million tonnes of styrene were produced in 2010, increasing to around 35 million tonnes by 2018.

<span class="mw-page-title-main">Chloroethane</span> Chemical compound commonly known as ethyl chloride

Chloroethane, commonly known as ethyl chloride, is a chemical compound with chemical formula CH3CH2Cl, once widely used in producing tetraethyllead, a gasoline additive. It is a colorless, flammable gas or refrigerated liquid with a faintly sweet odor.

Acrylonitrile is an organic compound with the formula CH2CHCN and the structure H2C=CH−C≡N. It is a colorless, volatile liquid. It has a pungent odor of garlic or onions. Its molecular structure consists of a vinyl group linked to a nitrile. It is an important monomer for the manufacture of useful plastics such as polyacrylonitrile. It is reactive and toxic at low doses.

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

Malathion is an organophosphate insecticide which acts as an acetylcholinesterase inhibitor. In the USSR, it was known as carbophos, in New Zealand and Australia as maldison and in South Africa as mercaptothion.

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

Cyclohexanol is the organic compound with the formula HOCH(CH2)5. The molecule is related to cyclohexane by replacement of one hydrogen atom by a hydroxyl group. This compound exists as a deliquescent colorless solid with a camphor-like odor, which, when very pure, melts near room temperature. Millions of tonnes are produced annually, mainly as a precursor to nylon.

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

Bromoform is an organic compound with the chemical formula CHBr3. It is a colorless liquid at room temperature, with a high refractive index and a very high density. Its sweet odor is similar to that of chloroform. It is one of the four haloforms, the others being fluoroform, chloroform, and iodoform. It is a brominated organic solvent. Currently its main use is as a laboratory reagent. It is very slightly soluble in water and is miscible with alcohol, benzene, chloroform, ether, petroleum ether, acetone and oils.

<span class="mw-page-title-main">1,4-Dioxane</span> Chemical compound

1,4-Dioxane is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers are rarely encountered.

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

p-Xylene (para-xylene) is an aromatic hydrocarbon. It is one of the three isomers of dimethylbenzene known collectively as xylenes. The p- stands for para-, indicating that the two methyl groups in p-xylene occupy the diametrically opposite substituent positions 1 and 4. It is in the positions of the two methyl groups, their arene substitution pattern, that it differs from the other isomers, o-xylene and m-xylene. All have the same chemical formula C6H4(CH3)2. All xylene isomers are colorless and highly flammable. The odor threshold of p-xylene is 0.62 parts per million (ppm).

<span class="mw-page-title-main">2-Butoxyethanol</span> Chemical compound

2-Butoxyethanol is an organic compound with the chemical formula BuOC2H4OH. This colorless liquid has a sweet, ether-like odor, as it derives from the family of glycol ethers, and is a butyl ether of ethylene glycol. As a relatively nonvolatile, inexpensive solvent, it is used in many domestic and industrial products because of its properties as a surfactant. It is a known respiratory irritant and can be acutely toxic, but animal studies did not find it to be mutagenic, and no studies suggest it is a human carcinogen. A study of 13 classroom air contaminants conducted in Portugal reported a statistically significant association with increased rates of nasal obstruction and a positive association below the level of statistical significance with a higher risk of obese asthma and increased body mass index.

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

Benzotrichloride (BTC), also known as α,α,α-trichlorotoluene, phenyl chloroform or (trichloromethyl)benzene, is an organic compound with the formula C6H5CCl3. Benzotrichloride is an unstable, colorless or somewhat yellowish, viscous, chlorinated hydrocarbon with a penetrating odor. Benzotrichloride is used extensively as a chemical intermediate for products of various classes, i.e. dyes and antimicrobial agents.

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

Ethyl acrylate is an organic compound with the formula CH2CHCO2CH2CH3. It is the ethyl ester of acrylic acid. It is a colourless liquid with a characteristic acrid odor. It is mainly produced for paints, textiles, and non-woven fibers. It is also a reagent in the synthesis of various pharmaceutical intermediates.

<span class="mw-page-title-main">1,1,2,2-Tetrachloroethane</span> Chemical compound

1,1,2,2-tetrachloroethane (TeCA), also known by the brand names Bonoform, Cellon and Westron, is an organic compound. It is colorless liquid and has a sweet odor. It is used as an industrial solvent and as a separation agent. TeCA is toxic and it can be inhaled, consumed or absorbed through the skin. After exposure, nausea, dizziness or even liver damage may occur.

4,4′-Methylenebis(2-chloroaniline) is a substance used as a curing agent in polyurethane production. MOCA is an aromatic amine which is structurally similar to benzidine, a known human bladder carcinogen. MOCA has been shown to cause hepatomas in mice and rats, lung and mammary carcinomas in rats and bladder cancer in dogs. It is a proven human carcinogen standing on the WHO List of IARC Group 1 carcinogens, with a current threshold limit value of 0.01 ppm in the industrial atmosphere. Animal studies have resulted in tumor growth in the liver, lung, and bladder.

<span class="mw-page-title-main">Benzene</span> Hydrocarbon compound

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.

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

Sulfotep (also known as tetraethyldithiopyrophosphate and TEDP) is a pesticide commonly used in greenhouses as a fumigant. The substance is also known as Dithione, Dithiophos, and many other names. Sulfotep has the molecular formula C8H20O5P2S2 and belongs to the organophosphate class of chemicals. It has a cholinergic effect, involving depression of the cholinesterase activity of the peripheral and central nervous system of insects. The transduction of signals is disturbed at the synapses that make use of acetylcholine. Sulfotep is a mobile oil that is pale yellow-colored and smells like garlic. It is primarily used as an insecticide.

Methacrylonitrile, MeAN in short, is a chemical compound that is an unsaturated aliphatic nitrile, widely used in the preparation of homopolymers, copolymers, elastomers, and plastics and as a chemical intermediate in the preparation of acids, amides, amines, esters, and other nitriles. MeAN is also used as a replacement for acrylonitrile in the manufacture of an acrylonitrile/butadiene/styrene-like polymer. It is a clear and colorless liquid, that has a bitter almond smell.

Benzo(<i>c</i>)fluorene Chemical compound

Benzo[c]fluorene is a polycyclic aromatic hydrocarbon (PAH) with mutagenic activity. It is a component of coal tar, cigarette smoke and smog and thought to be a major contributor to its carcinogenic properties. The mutagenicity of benzo[c]fluorene is mainly attributed to formation of metabolites that are reactive and capable of forming DNA adducts. According to the KEGG it is a group 3 carcinogen. Other names for benzo[c]fluorene are 7H-benzo[c]fluorene, 3,4-benzofluorene, and NSC 89264.

References

  1. 1 2 3 4 NIOSH Pocket Guide to Chemical Hazards. "#0264". National Institute for Occupational Safety and Health (NIOSH).
  2. ↑ Lange's Handbook of Chemistry (15th ed.). 1999.
  3. ↑ "Ethyl benzene". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. 1 2 3 4 5 6 7 "Ethylbenzene ToxFAQs" (PDF). Agency for Toxic Substances and Disease Registry. Retrieved 21 May 2018.
  5. 1 2 3 4 "ETHYLBENZENE : ENVIRONMENTAL, HEALTH & SAFETY GUIDELINES". CEFIC. Archived from the original on 19 September 2014. Retrieved 14 February 2013.
  6. ↑ "Ethylbenzene (EB) Production and Manufacturing Process". PIERS. Retrieved 14 February 2013.
  7. ↑ Summary shell moerdijk onderzoeksraad.nl July 2018
  8. 1 2 Vincent A.Welch, Kevin J. Fallon, Heinz-Peter Gelbke “Ethylbenzene” Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi : 10.1002/14356007.a10_035.pub2
  9. ↑ "Technology Transfer Network Air Toxics Web Site: Ethylbenzene". US Environmental Protection Agency. Retrieved 13 February 2013.
  10. ↑ "Ethylbenzene". eco-usa.net. Archived from the original on 25 December 2012. Retrieved 12 February 2013.
  11. ↑ 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.
  12. ↑ Francesc X. PRENAFETA-BOLDU; Andrea KUHN; Dion M. A. M. LUYKX; Heidrun ANKE; Johan W. van GROENESTIJN; Jan A. M. de BONT (April 2001). "Isolation and characterisation of fungi growing on volatile aromatic hydrocarbons as their sole carbon and energy source". Mycological Research. 105 (4): 477–484. doi:10.1017/s0953756201003719.
  13. ↑ Rabus, R.; Widdel, F. (1995). "Anaerobic degradation of ethylbenzene and other aromatic hydrocarbons by new denitrifying bacteria". Archives of Microbiology. 163 (2): 96–103. doi:10.1007/s002030050177. PMID   7710331.
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