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As a new associate editor (and previous guest editor) of the European Journal of Lipid Science and Technology, I would like to share some thoughts about ideal feedstock requirements with you. My group is involved in the utilization of renewable raw materials, especially plant oils, for the synthesis of monomers and polymers that might be able to replace existing materials based on fossil resources. Inspired by our daily work with all its ups and downs, I thought it might be interesting to communicate a wish list of oleochemical feedstock requirements to the community. Who knows, maybe somebody already has some answers?

Oleochemistry is a long established branch of industrial chemistry that has its roots in soap making for centuries and was also influenced by the invention of catalytic plant oil hydrogenation by Wilhelm Norman and its fast implementation on industrial scale during the early 20th century. Nowadays, the products of oleochemistry are manifold and range from basic starting materials (e.g., fatty alcohols and fatty acids) to detergents, lubricants, paints, coatings, and many others. In order to establish new industrial uses of plant oil derivatives, a continuous effort on basic research on new oleochemicals is necessary 1. In a chemist's point of view, and in order to invent new processes that are sustainable and along the lines of “green” chemistry, new feedstocks with the highest possible content of only one fatty acid would be very beneficial. In this respect, high oleic sunflower oil and castor oil, which are available on a large scale and have oleic and ricinoleic acid contents exceeding 90%, respectively, are prime feedstocks for the synthesis of oleochemicals. Especially castor oil has a well-developed industrial chemistry with countless application possibilities of its derivatives 2. However, these are only two examples and further breeding and/or genetic engineering is necessary in order to develop more oils with such characteristics.

Coming back to the chemist's point of view, a wish list for an oleochemical feedstock might include (but is not limited to) (i) oils with content of a certain fatty acid exceeding 90%, (ii) availability of fatty acids with free choice of the amount and position of the double bond(s), (iii) functional group containing fatty acids, and especially (iv) ω-functionalized fatty acids of various chain lengths. Some of the associated advantages would be: (i) no need of pre-purification or component enrichment associated with higher yield and less waste; (ii) easy introduction of established double bond follow up chemistry, but resulting in new and desired and required products (e.g., moving the double bond position in oleic acid from Δ-9 selectively to any other position and subsequent ozonolysis or cross-metathesis would make different chain length diacids for polycondensation chemistry available); (iii) no need for additional chemical or biotechnological conversion; (iv) availability of polycondensation monomers for renewable polyesters and polyamides. Such engineered oils might not only come from plant oils, but possibly also from algae or micro-organisms 3. In any case, the selective and sustainable chemical transformation in combination with biotechnology (e.g., enzymatic conversions, fermentation, genetic engineering, …) will be a key for the development of new oleochemical products. An excellent current example in the field of chemistry is the selective synthesis of ω-functionalized fatty acids via an isomerizing methoxycarbonylation of methyl oleate 4 (or methyl linoleate and linolenate) and methyl erucate and the subsequent polycondensation of the resulting α,ω-diesters to materials that have the potential to substitute polyethylene 5. An equally important breakthrough was achieved via biotechnology, when a Candida tropicalis strain was engineered to produce commercially viable yields of ω-hydroxyfatty acids 6. More of such outstanding examples of chemistry and biotechnology, in combination with the mentioned optimal feedstocks, will be needed in order to meet the future challenges, not only in oleochemistry, but in our society.

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