Cyclopentane

Cyclopentane is a highly flammable alicyclic hydrocarbon with chemical formula C5H10 and CAS number 287-92-3, consisting of a ring of five carbon atoms each bonded with two hydrogen atoms above and below the plane. It occurs as a colorless liquid with a petrol-like odor. Its melting point is −94 °C and its boiling point is 49 °C. Cyclopentane is in the class of cycloalkanes, being alkanes that have one or more rings of carbon atoms. It is formed by cracking cyclohexane in the presence of alumina at a high temperature and pressure.

Cyclopentane
Skeletal formula
Space-filling model
Names
IUPAC name
Cyclopentane
Other names
pentamethylene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.005.470
EC Number
  • 206-016-6
RTECS number
  • GY2390000
UNII
Properties
C5H10
Molar mass 70.1 g/mol
Appearance clear, colorless liquid
Odor mild, sweet
Density 0.751 g/cm3
Melting point −93.9 °C (−137.0 °F; 179.2 K)
Boiling point 49.2 °C (120.6 °F; 322.3 K)
156 mg·l−1 (25 °C)[1]
Solubility soluble in ethanol, acetone, ether
Vapor pressure 45 kPa (20 °C) [2]
Acidity (pKa) ~45
-59.18·10−6 cm3/mol
1.4065
Hazards
Main hazards Flammable[3]
NFPA 704 (fire diamond)
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 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
1
0
Flash point −37.2 °C (−35.0 °F; 236.0 K)
361 °C (682 °F; 634 K)
Explosive limits 1.1%-8.7%[3]
NIOSH (US health exposure limits):
PEL (Permissible)
 none[3]
REL (Recommended)
 TWA 600 ppm (1720 mg/m3)[3]
IDLH (Immediate danger)
 N.D.[3]
Related compounds
Related compounds
 cyclopropane, cyclobutane, cyclohexane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

It was first prepared in 1893 by the German chemist Johannes Wislicenus.[4]

Industrial usage

Cyclopentane is used in the manufacture of synthetic resins and rubber adhesives and also as a blowing agent in the manufacture of polyurethane insulating foam, as found in many domestic appliances such as refrigerators and freezers, replacing alternatives such as CFC-11 and HCFC-141b.[5]

Multiply alkylated cyclopentane (MAC) lubricants have low volatility and are used in some specialty applications.[6]

Formulation of cycloalkanes

Cycloalkanes can be formulated via a process known as catalytic reforming.

For example, 2-methylbutane can be reformed into cyclopentane, by use of a platinum catalyst. This is particularly well known in automobiles, as branched alkanes will burn much more readily.

Conformations
  • Envelope.
  • 3D envelope.
  • Half-chair.

References
  1. Record of cyclopentane in the GESTIS Substance Database of the Institute for Occupational Safety and Health, accessed on 28 February 2015.
  2. http://www.ilo.org/dyn/icsc/showcard.display?p_version=2&p_card_id=0353
  3. NIOSH Pocket Guide to Chemical Hazards. "#0171". National Institute for Occupational Safety and Health (NIOSH).
  4. J. Wislicenus and W. Hentschel (1893) "Der Pentamethenylalkohol und seine Derivate" (Cyclopentanol and its derivatives), Annalen der Chemie, 275 : 322-330; see especially pages 327-330. Wislicenus prepared cyclopentane from cyclopentanone ("Ketopentamethen"), which is prepared by heating calcium adipate.
  5. Greenpeace - Appliance Insulation Archived 2008-10-30 at the Wayback Machine
  6. Pennzane - lubrication technology
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.