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.
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||70.1 g/mol|
|Appearance||clear, colorless liquid|
|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)|
|Solubility||soluble in ethanol, acetone, ether|
|Vapor pressure||45 kPa (20 °C) |
Refractive index (nD)
|NFPA 704 (fire diamond)|
|Flash point||−37.2 °C (−35.0 °F; 236.0 K)|
|361 °C (682 °F; 634 K)|
|NIOSH (US health exposure limits):|
|TWA 600 ppm (1720 mg/m3)|
IDLH (Immediate danger)
|cyclopropane, cyclobutane, cyclohexane|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
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 environmentally damaging alternatives such as CFC-11 and HCFC-141b
Multiply alkylated cyclopentane (MAC) lubricants have low volatility and are used in some specialty applications.
The United States produces more than 500 tons of this chemical per year.
Formulation of cycloalkanesEdit
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.
- Record of cyclopentane in the GESTIS Substance Database of the Institute for Occupational Safety and Health, accessed on 28 February 2015.
- NIOSH Pocket Guide to Chemical Hazards. "#0171". National Institute for Occupational Safety and Health (NIOSH).
- 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.
- Greenpeace - Appliance Insulation Archived 2008-10-30 at the Wayback Machine
- Pennzane - lubrication technology
- Media related to Cyclopentane derivatives at Wikimedia Commons