Straight-chain terminal alkene
Industrially, linear alpha olefins are commonly manufactured by two main routes: oligomerization of ethylene and by Fischer–Tropsch synthesis followed by purification.
The only commercial process to isolate linear alpha olefins from synthetic crude is practiced by Sasol Ltd., a South African oil and gas and petrochemical company.
Dehydration of alcohols to linear alpha olefins by passing alcohols in a vapor phase over acidic alumina catalyst has been practiced periodically by Ethyl Corporation (later BP, now Ineos), Chevron Phillips, Sasol (formerly Vista Chemical) and Godrej Industries Ltd, an Indian petro- and specialty chemical company.
However, the process has been applied whenever the value of fatty alcohols dipped below that of linear olefins because of market dynamics or regional supply-demand issues.
One of the problems of the linear alpha olefin industry is the wide range of products made by most of the processes.
In the first step, a stoichiometric quantity of triethyl aluminium in olefin diluent is reacted with excess ethylene at high pressure (above 1000 psig) and relatively low temperature (below 400 °F).
The distribution of alkyl chains on the aluminium is determined by statistical bell curve distribution except for some smearing to the light side due to the kinetic phenomena and some smearing to the heavy side due to some incorporation of heavier olefins into the chain.
The heavy aluminium tri-alkyls are reacted with ethylene again in a displacement or a transalkylation reaction, but at high temperature (over 400 °F) and at low pressure (less than 1000 psig) to recover triethyl aluminium and a statistical distribution of linear alpha olefins, which serve as the olefin diluent in the chain-growth step.
The tri-ethyl aluminium catalyst is washed out of the product with caustic and the linear alpha olefins are separated.
Although C14 is more expensive than middle distillates, it has a significant advantage environmentally, being much more biodegradable and in handling the material, being much less irritating to skin and less toxic.
C16 - C18 linear olefins find their primary application as the hydrophobes in oil-soluble surfactants and as lubricating fluids themselves.
They are used in a number of reactive and non-reactive applications, including as feedstocks to make heavy linear alkyl benzene (LAB) and low molecular weight polymers which are used to enhance properties of waxes.
