P-Xylene

Last updated
p-Xylene
Skeletal formula Para-Xylol - para-xylene.svg
Skeletal formula
Space-filling model P-xylene-spaceFilling.png
Space-filling model
Space-filling model
Names
Preferred IUPAC name
1,4-Xylene [1]
Systematic IUPAC name
1,4-dimethylbenzene
Other names
p-Xylene, p-dimethylbenzene; p-xylol; 1,4-xylene; p-methyltoluene; [2] paraxylene; chromar; scintillar; 4-methyltoluene; [3] NSC 72419; or 1,4-dimethylbenzene. [4]
Identifiers
3D model (JSmol)
1901563
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.088 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 203-396-5
2697
KEGG
PubChem CID
RTECS number
  • ZE2625000
UNII
  • InChI=1S/C8H10/c1-7-3-5-8(2)6-4-7/h3-6H,1-2H3 X mark.svgN
    Key: URLKBWYHVLBVBO-UHFFFAOYSA-N X mark.svgN
  • InChI=1/C8H10/c1-7-3-5-8(2)6-4-7/h3-6H,1-2H3
    Key: URLKBWYHVLBVBO-UHFFFAOYAE
  • CC1=CC=C(C)C=C1
Properties
C8H10
Molar mass 106.168 g·mol−1
AppearanceColorless liquid
Odor Aromatic [5]
Density 0.861 g/mL
Melting point 13.2 °C (55.8 °F; 286.3 K)
Boiling point 138.35 °C (281.03 °F; 411.50 K)
Insoluble
Solubility in ethanol Very soluble
Solubility in diethyl ether Very soluble
Vapor pressure 9 mmHg (20°C) [5]
-76.78·10−6 cm3/mol
1.49582
Viscosity 0.7385 cP at 0 °C
0.6475 cP at 20 °C
0.00 D [6]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Harmful or if swallowed. Vapor maybe toxic. [7] Flammable liquid and vapor.
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg
Danger
H226, H302, H304, H312, H315, H319, H332, H335, H412
P210, P233, P240, P241, P242, P243, P261, P264, P271, P273, P280, P301+P310, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P312, P321, P322, P331, P332+P313, P337+P313, P362, P363, P370+P378, 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 27 °C (81 °F; 300 K) [8]
528 °C (982 °F; 801 K) [8]
Explosive limits 1.1%-7.0% [5]
100 ppm [8] (TWA), 150 ppm [8] (STEL)
Lethal dose or concentration (LD, LC):
4300 mg/kg [9]
4550 ppm (rat, 4 hr) [10]
3401 ppm (mouse) [10]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 100 ppm (435 mg/m3) [5]
REL (Recommended)
TWA 100 ppm (435 mg/m3) ST 150 ppm (655 mg/m3) [5]
IDLH (Immediate danger)
900 ppm [5]
Safety data sheet (SDS) External MSDS
Related compounds
benzene
toluene
o-xylene
m-xylene
Supplementary data page
P-Xylene (data page)
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 ?)

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). [11]

Contents

Production

The production of p-xylene is industrially significant, with annual demand estimated at 37 million tons in 2014, and still on the increase. [12] [13] p-Xylene is produced by catalytic reforming of petroleum naphtha as part of the BTX aromatics (benzene, toluene and the xylene isomers) extracted from the catalytic reformate. The p-xylene is then separated out in a series of distillation, adsorption or crystallization and reaction processes from the m-xylene, o-xylene, and ethylbenzene. Its melting point is the highest among this series of isomers, but simple crystallization does not allow easy purification due to the formation of eutectic mixtures.

Such separation procedures are major cost factors in the production of p-xylene, and the search for alternative methods continues. For example, a reverse-osmosis technique has been proposed to improve various aspects of the processes. [14]

Industrial applications

p-Xylene is an important chemical feedstock. Among other industrial applications, it is a raw material in the large scale synthesis of various polymers. In particular it is a component in the production of terephthalic acid for polyesters such as polyethylene terephthalate (generally known as PET). It also may be polymerised directly to produce parylene.

Oxidation p xylene.svg

Toxicity and exposure

Xylenes are not acutely toxic, for example the LD50 (rat, oral) is 4300 mg/kg. Effects vary with animal and xylene isomer.

Concerns with xylenes focus on narcotic effects. Overexposure of p-xylene in humans can cause headache, fatigue, dizziness, listlessness, confusion, irritability, gastrointestinal disturbances including nausea and loss of appetite, flushing of the face, and a feeling of increased body heat. p-Xylene vapor exposure over the recommended exposure limit of 100 parts per million (ppm) can cause irritation to eye, nose, and throat and possible chest tightening and an abnormal gait. [15]

p-Xylene occurs naturally in petroleum and coal tar. It is emitted by most combustion sources, including automobile exhaust and tobacco smoke. [16]

Inhalation

Inhaling p-xylene can cause dizziness, headache, drowsiness, and nausea. If exposure through inhalation occurs, first aid includes fresh air, rest and possible medical attention. Through the use of ventilation or breathing protection, exposure to p-xylene through inhalation can be prevented. [17]

Skin

Exposure of p-xylene through the skin can cause dry skin and redness. If skin exposure occurs, first aid includes rinsing and then washing the affected area with soap and water as well as removing any contaminated clothing and thoroughly cleaning and drying before reuse. Exposure can be prevented through the use of protective gloves. [17]

Eyes

Exposure of p-xylene to eyes can cause redness and pain. If eyes are exposed, first aid includes rinsing of the eyes with water for several minutes, removal of contact lenses if applicable, and medical attention. Eye exposure can be prevented through the use of safety glasses or safety goggles. [17]

Ingestion

Ingestion of p-xylene can result in a burning sensation, abdominal pain, dizziness, drowsiness, headache, and nausea. If p-xylene is ingested one's mouth should be rinsed and vomiting should not be induced. Further medical attention should be sought. Ingestion can be prevented by not eating, drinking, or smoking when working with p-xylene. [17]

Short-term exposure

p-Xylene can cause issues with the central nervous system and if swallowed could cause chemical pneumonitis when breathed into the lungs. [17]

Long-term exposure

Liquid p-xylene exposure to the skin over long periods of time can remove the fat from the skin. The substance may also have effects on the central nervous system. Exposure can enhance hearing loss caused by noise exposure. Animal tests suggest that this substance could cause damage to human development and reproductive systems. [17]

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 the 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">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">Heptane</span> Chemical compound

Heptane or n-heptane is the straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16. When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale (the 100 point is 100% iso-octane). Octane number equates to the anti-knock qualities of a comparison mixture of heptane and iso-octane which is expressed as the percentage of iso-octane in heptane, and is listed on pumps for gasoline (petrol) dispensed globally.

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

Dichloromethane is an organochlorine compound with the formula CH2Cl2. This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Although it is not miscible with water, it is slightly polar, and miscible with many organic solvents.

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

Nitrobenzene is an aromatic nitro compound and the simplest of the nitrobenzenes, with the chemical formula C6H5NO2. It is a water-insoluble pale yellow oil with an almond-like odor. It freezes to give greenish-yellow crystals. It is produced on a large scale from benzene as a precursor to aniline. In the laboratory, it is occasionally used as a solvent, especially for electrophilic reagents. As confirmed by X-ray crystallography, nitrobenzene is a planar molecule.

Chemical hazards are hazards present in hazardous chemicals and hazardous materials. Exposure to certain chemicals can cause acute or long-term adverse health effects. Chemical hazards are usually classified separately from biological hazards (biohazards). Chemical hazards are classified into groups that include asphyxiants, corrosives, irritants, sensitizers, carcinogens, mutagens, teratogens, reactants, and flammables. In the workplace, exposure to chemical hazards is a type of occupational hazard. The use of personal protective equipment may substantially reduce the risk of adverse health effects from contact with hazardous materials.

Demeton-S-methyl is an organic compound with the molecular formula C6H15O3PS2. It was used as an organothiophosphate acaricide and organothiophosphate insecticide. It is flammable. With prolonged storage, Demeton-S-methyl becomes more toxic due to formation of a sulfonium derivative which has greater affinity to the human form of the acetylcholinesterase enzyme, and this may present a hazard in agricultural use.

<span class="mw-page-title-main">Ethylbenzene</span> Hydrocarbon compound; precursor to styrene and polystyrene

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.

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

The chemical compound isobutyl acetate, also known as 2-methylpropyl ethanoate or β-methylpropyl acetate, is a common solvent. It is produced from the esterification of isobutanol with acetic acid. It is used as a solvent for lacquer and nitrocellulose. Like many esters it has a fruity or floral smell at low concentrations and occurs naturally in raspberries, pears and other plants. At higher concentrations the odor can be unpleasant and may cause symptoms of central nervous system depression such as nausea, dizziness and headache.

<i>sec</i>-Butyl acetate Chemical compound

sec-Butyl acetate, or s-butyl acetate, is an ester commonly used as a solvent in lacquers and enamels, where it is used in the production of acyclic polymers, vinyl resins, and nitrocellulose. It is a clear flammable liquid with a sweet smell.

1,1,2-Trichloroethane, vinyl trichloride or 1,1,2-TCA, is an organochloride solvent with the molecular formula C2H3Cl3 and the structural formula CH2Cl—CHCl2. It is a colourless, sweet-smelling liquid that does not dissolve in water, but is soluble in most organic solvents. It is an isomer of 1,1,1-trichloroethane, and a byproduct of its manufacture.

<span class="mw-page-title-main">Dichlorvos</span> Insect killing chemical, organophosphate

Dichlorvos is an organophosphate widely used as an insecticide to control household pests, in public health, and protecting stored products from insects. The compound has been commercially available since 1961. It has become controversial because of its prevalence in urban waterways and the fact that its toxicity extends well beyond insects. Since 1988, dichlorvos cannot be used as a plant protection product in the EU.

<span class="mw-page-title-main">Butane-1-thiol</span> Chemical compound

Butane-1-thiol, also known as butyl mercaptan, is a volatile, clear to yellowish liquid with a fetid odor, commonly described as "skunk" odor. In fact, 1-butanethiol is structurally similar to several major constituents of a skunk's defensive spray but is not actually present in the spray. The scent of 1-butanethiol is so strong that the human nose can easily detect it in the air at concentrations as low as 10 parts per billion. The threshold level for 1-butanethiol is reported as 1.4 ppb

<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.

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

Thiram is the simplest thiuram disulfide and the oxidized dimer of dimethyldithiocarbamate. It is used as a fungicide, ectoparasiticide to prevent fungal diseases in seed and crops and similarly as an animal repellent to protect fruit trees and ornamentals from damage by rabbits, rodents and deer. It is effective against Stem gall of coriander, damping off, smut of millet, neck rot of onion, etc. Thiram has been used in the treatment of human scabies, as a sun screen and as a bactericide applied directly to the skin or incorporated into soap.

<span class="mw-page-title-main">Manure management</span> Agricultural practice

Manure management refers to capture, storage, treatment, and utilization of animal manures in an environmentally sustainable manner. It can be retained in various holding facilities. Animal manure can occur in a liquid, slurry, or solid form. It is utilized by distribution on fields in amounts that enrich soils without causing water pollution or unacceptably high levels of nutrient enrichment. Manure management is a component of nutrient management.

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

Demeton, sold as an amber oily liquid with a sulphur like odour under the name Systox, is an organophosphate derivative causing irritability and shortness of breath to individuals repeatedly exposed. It was used as a phosphorothioate insecticide and acaricide and has the chemical formula C8H19O3PS2. Although it was previously used as an insecticide, it is now largely obsolete due to its relatively high toxicity to humans. Demeton consists of two components, demeton-S and demeton-O in a ratio of approximately 2:1 respectively. The chemical structure of demeton is closely related to military nerve agents such as VX and a derivative with one of the ethoxy groups replaced by methyl was investigated by both the US and Soviet chemical-weapons programs under the names V-sub x and GD-7.

<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.

<i>n</i>-Butyl lactate Chemical compound

n-Butyl lactate is an industrial chemical and food additive.

1-Octanethiol, also called 1-mercaptooctane, is an organic compound.

References

  1. Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 139. doi:10.1039/9781849733069. ISBN   978-0-85404-182-4.
  2. Not to be used
  3. Archaic name
  4. "p-xylene". NIST. Retrieved 21 February 2013.
  5. 1 2 3 4 5 6 NIOSH Pocket Guide to Chemical Hazards. "#0670". National Institute for Occupational Safety and Health (NIOSH).
  6. Perry's Handbook of Chemical Engineers
  7. P-Xylene: main hazards
  8. 1 2 3 4 "p-Xylene". International Chemical Safety Cards. ICSC/NIOSH. July 1, 2014.
  9. P-Xylene: toxicity for rats
  10. 1 2 "Xylenes". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  11. "p-Xylene MSDS". ScienceLab.com.{{cite web}}: Missing or empty |url= (help)
  12. Fabri, Jörg; Graeser, Ulrich; Simo, Thomas A. (2000). Ullmann's Encyclopedia of Industrial Chemistry. Wiley Online Library. doi:10.1002/14356007. ISBN   9783527303854.
  13. Nature 532,435–437 (28 April 2016) doi:10.1038/532435a
  14. Koh, D. Y.; McCool, B. A.; Deckman, H. W.; Lively, R. P. (2016). "Reverse osmosis molecular differentiation of organic liquids using carbon molecular sieve membrane". Science. 353 (6301): 804–7. Bibcode:2016Sci...353..804K. doi:10.1126/science.aaf1343. PMID   27540170. S2CID   9480478.
  15. "Material Safety Data Sheet – Para-Xylene". Amoco. Archived from the original on 4 March 2016. Retrieved 13 February 2013.
  16. EPA-454/R-93-048 Locating and estimating air emissions from sources of xylene Emission Inventory Branch Technical Support Division Office of Air Quality Planning and Standards U.S. Environmental Protection Agency March 1994
  17. 1 2 3 4 5 6 "para-Xylene". National Institute for Occupational Safety and Health. Retrieved 12 February 2013.