Editing Propylene (section)

===Steam cracking===
{{main|Steam cracking}}
The dominant technology for producing propylene is [[steam cracking]], using [[propane]] as the [[feedstock]]. Cracking propane yields a mixture of [[ethylene]], propylene, [[methane]], [[hydrogen gas]], and other related compounds.  The yield of propylene is about 15%.  The other principal feedstock is [[naphtha]], especially in the [[Middle East]] and Asia.<ref>Ashford's Dictionary of Industrial Chemicals, Third edition, 2011, {{ISBN|978-0-9522674-3-0}}, pages 7766-9</ref> 
Propylene can be separated by [[fractional distillation]] from the hydrocarbon mixtures obtained from cracking and other refining processes; refinery-grade propene is about 50 to 70%.<ref name=Dow>{{cite web |url=http://www.dow.com/productsafety/finder/pro.htm |title=Product Safety Assessment(PSA): Propylene |publisher=Dow Chemical Co. |access-date=2011-07-11 |archive-url=https://web.archive.org/web/20130828163039/http://www.dow.com/productsafety/finder/pro.htm |archive-date=2013-08-28  }}</ref> In the United States, [[shale gas]] is a major source of propane.