Cumene

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Cumene
Skeletal formula of cumene
Ball-and-stick model of the cumene molecule
Names
Preferred IUPAC name
(Propan-2-yl)benzene[1]
Other names
  • Cumene
  • Isopropylbenzene
  • Cumol
  • (1-Methylethyl)benzene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.002.458
KEGG
RTECS number GR8575000
UNII
Properties
C9H12
Molar mass 120.20 g·mol−1
Appearance colorless liquid
Odor sharp, gasoline-like
Density 0.862 g cm−3, liquid
Melting point −96 °C (−141 °F; 177 K)
Boiling point 152 °C (306 °F; 425 K)
negligible
Solubility soluble in acetone, ether, ethanol
Vapor pressure 8 mm (20°C)[2]
-89.53·10−6 cm3/mol
1.4915 (20 °C)
Viscosity 0.777 cP (21 °C)
Hazards
Main hazards flammable
R-phrases (outdated) R10,R37,R51/53,R65
S-phrases (outdated) S24,S37,S61,S62
NFPA 704
Flammability code 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., gasolineHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroformReactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calciumSpecial hazards (white): no codeNFPA 704 four-colored diamond
3
2
1
Flash point 43 °C (109 °F; 316 K)
424 °C (795 °F; 697 K)
Explosive limits 0.9-6.5%
Lethal dose or concentration (LD, LC):
12750 mg/kg (oral, mouse)
1400 mg/kg (oral, rat)[3]
200 ppm (mouse, 7 hr)[3]
8000 ppm (rat, 4 hr)[3]
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 50 ppm (245 mg/m3) [skin][2]
REL (Recommended)
TWA 50 ppm (245 mg/m3) [skin][2]
IDLH (Immediate danger)
900 ppm[2]
Related compounds
Related compounds
ethylbenzene
toluene
benzene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☑Y verify (what is ☑Y‹See TfM›☒N ?)
Infobox references

Cumene (isopropylbenzene) is an organic compound that is based on an aromatic hydrocarbon with an aliphatic substitution. It is a constituent of crude oil and refined fuels. It is a flammable colorless liquid that has a boiling point of 152 °C. Nearly all the cumene that is produced as a pure compound on an industrial scale is converted to cumene hydroperoxide, which is an intermediate in the synthesis of other industrially important chemicals, primarily phenol and acetone.

Production[edit]

Cumene-formation-2D-skeletal V2.svg

Commercial production of cumene is by Friedel–Crafts alkylation of benzene with propylene. Cumene producers account for approximately 20% of the global demand for benzene.[4] The original route for manufacturing of cumene was by alkylation of benzene in the liquid phase using sulfuric acid as a catalyst, but because of the complicated neutralization and recycling steps required, together with corrosion problems, this process has been largely replaced. As an alternative, solid phosphoric acid (SPA) supported on alumina was used as the catalyst. Since the mid-1990s, commercial production has switched to zeolite-based catalysts.[5] In this process, the efficiency of cumene production is generally 70-75%. The remaining components are primarily polyisopropyl benzenes. In 1976, an improved cumene process that uses aluminum chloride as a catalyst was developed. The overall conversion of cumene for this process can be as high as 90%.

The addition of two equivalents of propylene gives diisopropylbenzene (DIPB). Using transalkylation, DIPB is comproportionated with benzene.[6]

Safety[edit]

Cumene forms peroxides upon long exposure to air.[7] Tests for peroxides are routinely conducted before heating or distilling.

References[edit]

  1. ^ Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 139, 597. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
  2. ^ a b c d "NIOSH Pocket Guide to Chemical Hazards #0159". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ a b c "Cumene". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. ^ Market Study Benzene, published by Ceresana, July 2011 [1]
  5. ^ The Innovation Group website, page accessed 15/11/07
  6. ^ Bipin V. Vora, Joseph A. Kocal, Paul T. Barger, Robert J. Schmidt, James A. Johnson (2003). "Alkylation". Kirk‐Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.0112112508011313.a01.pub2.
  7. ^ CDC - NIOSH Pocket Guide to Chemical Hazards

External links[edit]