cyclopropane(redirected from Cyclopropanes)
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(also trimethylene), an alicyclic hydrocarbon having the structural formula
Cyclopropane is a colorless gas with a boiling point of –32.8°C and a density of 0.720 g/cm3 at –79°C. Insoluble in water, it is soluble in alcohol and ether.
Cyclopropane is the first member of the homologous series of cycloparaffins. Its trimethylene ring, however, is characterized by reactions of the C═C double bond; for example, it forms 1,3-dibromopropane (BrCH2CH2CH2Br) in its reaction with bromine. The cyclopropane ring is easily broken because it is strained. Nevertheless, in contrast to olefins, cyclopropane does not react with potassium permanganate and ozone at 20°C. Cyclopropane and hydrocarbons containing the cyclopropane ring may be obtained by reacting zinc dust with derivatives that have two halogens attached at the 1 and 3 positions. They may also be obtained by other methods, including the joining of carbenes to olefins.
Cyclopropane and its derivatives are of great theoretical interest; for example, it has been discovered that compounds containing the cyclopropenyl cation have aromatic properties. The cyclopropane ring is found in biologically important natural compounds (seePYRETHRINS). Cyclopropane itself is used as an anesthetic.