P-Xylene

p-Xylene
Skeletal formula
Space-filling model
Space-filling model
Names
Preferred IUPAC name
1,4-Xylene[4]
Systematic IUPAC name
1,4-dimethylbenzene
Other names
p-Xylene, p-dimethylbenzene; p-xylol; 1,4-xylene; p-methyltoluene;[1] paraxylene; chromar; scintillar; 4-methyltoluene;[2] NSC 72419; or 1,4-dimethylbenzene.[3]
Identifiers
3D model (JSmol)
1901563
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.003.088 Edit this at Wikidata
EC Number
  • 203-396-5
2697
KEGG
RTECS number
  • ZE2625000
UNII
  • InChI=1S/C8H10/c1-7-3-5-8(2)6-4-7/h3-6H,1-2H3 ☒N
    Key: URLKBWYHVLBVBO-UHFFFAOYSA-N ☒N
  • 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
Appearance Colorless 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:
GHS02: FlammableGHS07: Exclamation markGHS08: Health hazard
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 four-colored diamondHealth 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).
☒N verify (what is checkY☒N ?)

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]

  1. ^ Not to be used
  2. ^ Archaic name
  3. ^ "p-xylene". NIST. Retrieved 21 February 2013.
  4. ^ 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.
  5. ^ a b c d e f 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. ^ a b c d "p-Xylene". International Chemical Safety Cards. ICSC/NIOSH. July 1, 2014.
  9. ^ P-Xylene: toxicity for rats
  10. ^ a b "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)