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||400 mmHg (31 °C)|
Refractive index (nD)
|Flash point||−37.2 °C (−35.0 °F; 236.0 K)|
|361 °C (682 °F; 634 K)|
|US health exposure limits (NIOSH):|
|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 half a million kilograms 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 Cyclopentanes at Wikimedia Commons