Researchers from Caltech and UC San Diego report very high performance catalysts to convert seed oils to olefins
Researchers from Caltech and UC San Diego have developed a family of ruthenium-based metathesis catalysts that have shown exceptional activity in the conversion of seed oils to linear-chain olefins. In many cases, catalyst turnover numbers (TONs) of more than 100 ,000 were achieved, at a catalyst loading of only 3 ppm. Remarkably, the most active catalyst system was able to achieve a TON of 340,000 at a catalyst loading of only 1 ppm.
A paper on their work is published in the journal Angewandte Chemie.
In a brief note highlighting the Caltech/UCSD work, Phil Szuromi at Science noted that linear-chain olefins are essential building blocks for both commodity products, such as lubricants and thermoplastics, and fine chemicals and drugs.
The ethanolysis of fatty acids derived from seed oils could provide a renewable source of LAOs. However, most catalysts for this reaction deactivate after thousands of reaction cycles (turnovers) and thus require unacceptable amounts of catalyst.
The authors of the study observed that:
These catalysts exhibited exceptional activity in the ethenolysis of the seed-oil derivative methyl oleate. This is the first time a series of metathesis catalysts has exhibited such high performance in cross-metathesis reactions employing ethylene gas, with activities sufficient to render ethenolysis applicable to the industrial-scale production of linear α-olefins (LAOs) and other terminal-olefin products.—Marx et al.
Marx, V. M., Sullivan, A. H., Melaimi, M., Virgil, S. C., Keitz, B. K., Weinberger, D. S., Bertrand, G. and Grubbs, R. H. (2014), “Cyclic Alkyl Amino Carbene (CAAC) Ruthenium Complexes as Remarkably Active Catalysts for Ethenolysis” Angew. Chem. Int. Ed.. doi: 10.1002/anie.201410797
Phil Szuromi (2015) “Olefins from seed oils at industrial scales” Science doi: 10.1126/science.347.6221.516-f