Alkenes area class of HYDROCARBONS
which contain only carbon and hydrogen. Two other terms which
describe alkenes are unsaturated and olefins.
UNSATURATED hydrocarbons contain either double or triple
bonds. Since the compound is unsaturated with respect to hydrogen
atoms, the extra electrons are shared between 2 carbon atoms
forming double bonds in alkenes.
Alkenes are also called OLEFINS because they form oily
liquids on reaction with chlorine gas.
The example compounds of ethene or ethylene and pentene are
shown on the LEFT.
Ethylene is the number one organic chemical synthesized in
the U. S. and the world. The small quantities of ethane, propane,
and butane found in natural gas are converted into ethene. It
can be produced by thermal cracking of ethane to produce ethene
and a hydrogen molecule.
Alkenes are the raw materials for a number of plastics such
as polyethylene, PVC, polypropylene, and polystyrene.
Alkene chemistry is found in unsaturated fats, beta-carotene,
and seeing light through vision.