Cyclopentane

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Cyclopentane
Skeletal formula Space-filling model
Identifiers
CAS number 287-92-3 YesY
PubChem 9253
ChemSpider 8896 YesY
EC number 206-016-6
ChEBI CHEBI:23492 YesY
RTECS number GY2390000
Jmol-3D images Image 1
Properties
Molecular formula 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)
Solubility soluble in ethanol, acetone, ether
Acidity (pKa) ~45
Refractive index (nD) 1.4065
Hazards
Main hazards Flammable[1]
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., gasoline) Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point −37.2 °C (−35.0 °F; 236.0 K)
Related compounds
Related compounds cyclopropane, cyclobutane, cyclohexane
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

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.

The typical structure of cyclopentane is the "envelope" conformation.

It is formed by cracking cyclohexane in the presence of alumina at a high temperature and pressure.

It was first prepared in 1893 by the German chemist Johannes Wislicenus.[2]

Industrial usage[edit]

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[3]

More advanced technologies, such as computer hard drives and outerspace equipment employ multiply alkylated cyclopentane (MAC) lubricants because of their extremely low volatility.[4]

The United States produces more than half a million kilograms of this chemical per year.

Formulation of cycloalkanes[edit]

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.

Half-chair conformation of lower-energy state chemical structure of cyclopentane.

References[edit]

  1. ^ CDC - NIOSH Pocket Guide to Chemical Hazards
  2. ^ 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.
  3. ^ [1] Greenpeace - Appliance Insulation
  4. ^ [2] Pennzane - lubrication technology