<P> Alkenes are produced by hydrocarbon cracking . Raw materials are mostly natural gas condensate components (principally ethane and propane) in the US and Mideast and naphtha in Europe and Asia . Alkanes are broken apart at high temperatures, often in the presence of a zeolite catalyst, to produce a mixture of primarily aliphatic alkenes and lower molecular weight alkanes . The mixture is feedstock and temperature dependent, and separated by fractional distillation . This is mainly used for the manufacture of small alkenes (up to six carbons). </P> <P> Related to this is catalytic dehydrogenation, where an alkane loses hydrogen at high temperatures to produce a corresponding alkene . This is the reverse of the catalytic hydrogenation of alkenes . </P> <P> This process is also known as reforming . Both processes are endothermic and are driven towards the alkene at high temperatures by entropy . </P> <P> Catalytic synthesis of higher α - alkenes (of the type RCH = CH) can also be achieved by a reaction of ethylene with the organometallic compound triethylaluminium in the presence of nickel, cobalt, or platinum . </P>

Alkenes are useful intermediates in the synthesis of organic compounds