Metathesis with oleochemicals: a sustainable match to obtain monomers and polymers from renewable resources

In ages of depleting fossil reserves and increasing emission of green house gases it is obvious that the utilization of renewable feedstocks is one necessary step towards a sustainable development of our future. Especially plant derived oils bear a large potential for the substitution of currently used petrochemicals, since a variety of value added chemical intermediates can be derived from these resources in a straightforward fashion taking full advantage of nature’s synthetic potential. Here, new approaches for the synthesis of monomers as well as polymers from plant oils as renewable resources[1] via olefin metathesis[2,3] will be discussed.
As an example, we recently showed that different chain length α,ω-diester monomers can be obtained from plant oil derived fatty acid esters via olefin cross-metathesis[4] with methyl acrylate taking advantage of natures "synthetic pool" of fatty acids with different chain lengths and positions of double bonds.[5] Similarly, we could show that the cross-metathesis with allyl chloride and other functional olefins allows for the synthesis of α,ω-difunctional compounds.[6,7] Therefore, this strategy offers the possibility to introduce a variety of different functional groups to the ω-position of fatty acid derivatives, thus providing valuable starting materials for a variety of polyesters and polyamides.
Moreover, acyclic diene metathesis (ADMET), can be used to directly obtain macromolecules from such starting materials. The ADMET polymerization[8] of undecyl undecenoate, for instance, led to high molecular weight polyesters. [9] It was possible to efficiently control the molecular weight of these materials and to prepare telechelics via the application of mono-functional chain-stoppers.[9] More interestingly, this approach can also be used to prepare ABA triblock copolymers with control of the degree of polymerization (DP) of the B block in a single reaction step.[9] Furthermore, if tri-functional monomers in combination with chain stoppers are investigated the synthesis of hyperbranched polymer architectures with functional groups in their periphery can be achieved in a single reaction step.[10]

Acknowledgement. Financial support from the Fachagentur Nachwachsende Rohstoffe (FKZ 22026905) is kindly acknowledged.

References:
[1] M. A. R. Meier, J. O. Metzger, U. S. Schubert, Chem. Soc. Rev. 2007, 36, 1788. [2] R. H. Grubbs, Angew. Chem. Int. Ed. 2006, 45, 3760-3765. [3] A. Rybak, P. A. Fokou, M. A. R. Meier, Eur. J. Lipid Sci. Technol. 2008, 110, 797. [4] S. J. Connon, S. Blechert, Angew. Chem. Int. Ed. 2003, 42, 1900. [5] A. Rybak, M. A. R. Meier, Green Chem. 2007, 9, 1356. [6] A. Rybak, M. A. R. Meier, Green Chem. 2008, 10, 1099. [7] T. Jacobs, A. Rybak, M. A. R. Meier, Appl. Catal., A 2008, DOI:10.1016/j.apcata.2008.10.026. [8] T. W. Baughman, K. B. Wagener, Adv. Polym. Sci. 2005, 176, 1. [9] A. Rybak, M. A. R. Meier, ChemSusChem 2008, 1, 542. [10] P. A. Fokou, M. A. R. Meier, Macromol. Rapid Commun. 2008, 29, 1620.