Technology Type

Oligomerization of olefins higher than ethylene (C₃ and above) is a family of catalytic processes that convert light olefins—such as propene, butenes, hexenes, and longer-chain alpha-olefins—into higher molecular weight products. These processes are essential in the petrochemical industry for producing intermediates used in fuels, plasticizers, lubricants, and specialty chemicals.

Dimerization and Oligomerization of C₃–C₄ Olefins

• Dimerization: Monomers like propene and butenes are catalytically coupled to form dimers (e.g., hexenes from propene, octenes from butenes). This is typically achieved using homogeneous or heterogeneous catalysts, such as nickel complexes or solid acids. The resulting, predominantly branched dimers are valuable for further conversion into plasticizer alcohols or as high-octane gasoline components.

• Oligomerization: Beyond dimerization, these olefins can be further oligomerized to produce trimers, tetramers, and higher oligomers, depending on catalyst and process conditions. The product distribution (dimers vs. higher oligomers) is controlled by catalyst design and reaction parameters.

Oligomerization of Higher Alpha-Olefins (C₄⁺)

• Linear Alpha-Olefin Oligomerization: Pure 1-butene, 1-hexene, 1-octene, and higher alpha-olefins (up to C₂₀–C₃₀) can be oligomerized to produce blends of linear alpha-olefins (LAOs) with higher carbon numbers. These processes are typically catalyzed by transition metal complexes (often Ni, Ti, or Zr based), sometimes in the presence of co-catalysts or in ionic liquid media.

• Product Range: The process can be tuned to favor specific chain lengths or to produce blends in defined ranges (e.g., C₂₀–C₂₄, C₂₄–C₃₀, C₂₀–C₃₀). These LAO blends are used in lubricants, surfactants, and specialty chemicals.

Process Options

• Homogeneous Catalysis: Uses soluble transition metal complexes, often with co-catalysts, for high activity and selectivity. This is common for both dimerization and oligomerization of light and higher olefins.

• Heterogeneous Catalysis: Employs solid catalysts such as zeolites or supported metal complexes, offering easier separation and potential for continuous operation.

• Ionic Liquid Systems: Recent advances include biphasic systems where the catalyst is dissolved in an ionic liquid, improving selectivity, catalyst stability, and ease of product separation.

Summary

In summary, the oligomerization of olefins higher than ethylene encompasses a spectrum of processes:

• Dimerization of C₃–C₄ olefins (e.g., propene to hexenes, butenes to octenes).
• Oligomerization of C₃–C₆⁺ olefins to produce higher branched or linear oligomers.
• Oligomerization of pure higher alpha-olefins (1-butene, 1-hexene, 1-octene, etc.) to produce LAO blends in targeted carbon number ranges.

These processes are crucial for producing intermediates for fuels, plasticizers, lubricants, and specialty chemicals, and can be implemented using homogeneous, heterogeneous, or ionic liquid-based catalytic systems.

References

1. Marchionna, M., Di Girolamo, M., & Patrini, R. (2001). Light olefins dimerization to high quality gasoline components. Catalysis Today, 65(2-4), 397–403. doi:10.1016/s0920-5861(00)00587-3.
2. A. Forestière, H. Olivier-Bourbigou, L. Saussine. Oligomerization of Monoolefins by Homogeneous Catalysts. Oil & Gas Science and Technology - Revue d'IFP Energies nouvelles, 2009, 64 (6), pp.649-667. DOI: 10.2516/ogst/2009027.
3. H. Olivier-Bourbigou et al., Nickel Catalyzed Olefin Oligomerization and Dimerization, Chem. Rev. 2020, 120, 15, 7919–7983, DOI: 10.1021/acs.chemrev.0c00076.
4. Parfenova, L.V.; Bikmeeva, A.K.; Kovyazin, P.V.; Khalilov, L.M. The Dimerization and Oligomerization of Alkenes Catalyzed with Transition Metal Complexes: Catalytic Systems and Reaction Mechanisms. Molecules 2024, 29, 502. DOI: 10.3390/molecules29020502.