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12/3/2013 ECHE 430 1
Conversion of Ethylene to Higher Olefins Using Homogeneous Catalysis
By Timothy Barnhill, Joshua Blease, Hassan Abuthaibah, Nick Nadorff
Shell Higher Olefins Process
12/3/2013 ECHE 430 2
Higher Olefins in Industry
• Olefins (ethylene, butylene)– Key building blocks– High availability, reactivity, low cost
• Higher molecular weight olefins (C6-C20)– Synthetic automotive oils– Biodegradable surfactants– Stronger plastics
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Production of Higher Olefins
• Wax Pyrolyis (Chevron, 1966)– Conversion of 20-40% per pass– Higher conversions produced undesired aromatics
• Ethylene Oligomerization (Gulf Oil, 1966)– Production of wide variety of alkenes– Modifying selectivity for desired olefins was
difficult
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Shell Higher Olefin Process (1977)
• Able to adjust product output to meet market needs
• Produced α-olefins which could be sold as is• Converted olefins with low market value to
detergent range fatty alcohols (C6-C11)
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Process Overview
B. Reuben
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Process Overview• Oligomerization:
• Isomerization:
• Metathesis:
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Oligomerization
• Oligomer – Complex consisting of a few monomers
• Catalyst – Nickel complex• Ethylene “oligomerized” into even α-olefins– Desired olefins recovered by distillation– Non-marketable olefins sent to isomerization
(usually small (< C6) and large (> C18) olefins)
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OligomerizationMechanism
Ni Catalyst
Ligands added
CoordinationComplex
Ethylene reacts
Even-numberedα-olefins
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Isomerization
• Smaller and larger α-olefins isomerized to form internal double bonds
• Catalyst – Na/K on Al2O3
12/3/2013 ECHE 430 10
Metathesis
• Metathesis is defined as a catalytic reaction in which alkenes are converted into products by breaking and reforming C-C double bonds.
• Phillips Petroleum developed a unique reaction called olefin metathesis.
• Originally developed to convert cheap propylene into high value ethylene and 2-butene.
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Internal Olefins• The internal olefins pass to the metathesis reactor
where the short- and long-chain internal olefins disproportionate.
• After this the products of the metathesis reaction are fed to the fractionating column to separate desired C10-
14 olefins for hydroformulation.
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Applications of Linear Olefins
• Drilling Fluid: (C16 – C18) alpha olefins– Physical properties
• High purity• Viscosity
• Monomers: (C4 – C10) alpha olefins– Production of polymers
and polyethylene
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• Detergents: (C12 – C20) alpha olefins
• Plasticizers: (C6 – C10) alpha olefins– Production of plasticizer alcohols
and surfactants.
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References
“Shell Higher Olefins Process,” E.F. Lutz, Shell Development Company, Journal of Chemical Education, 63 (3) p. 202, 1986.
“The SHOP process: An example of industrial creativity,” Bryan Reuben and Harold Wittcoff, Journal of Chemical Education, 65 (7) p. 605, 1988.
“Developments in LAO Comonomer Technologies for Polyethylene,” Nexant, Inc., http://www.chemsystems.com/about/cs/news/items/PERP2011S11_LAOr.cfm