- Chain Multiplication of Fatty Acids to Precise Telechelic Polyethylene
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Starting from common monounsaturated fatty acids, a strategy is revealed that provides ultra-long aliphatic α,ω-difunctional building blocks by a sequence of two scalable catalytic steps that virtually double the chain length of the starting materials. The central double bond of the α,ω-dicarboxylic fatty acid self-metathesis products is shifted selectively to the statistically much-disfavored α,β-position in a catalytic dynamic isomerizing crystallization approach. “Chain doubling” by a subsequent catalytic olefin metathesis step, which overcomes the low reactivity of this substrates by using waste internal olefins as recyclable co-reagents, yields ultra-long-chain α,ω-difunctional building blocks of a precise chain length, as demonstrated up to a C48 chain. The unique nature of these structures is reflected by unrivaled melting points (Tm=120 °C) of aliphatic polyesters generated from these telechelic monomers, and by their self-assembly to polyethylene-like single crystals.
- Witt, Timo,H?u?ler, Manuel,Kulpa, Stefanie,Mecking, Stefan
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supporting information
p. 7589 - 7594
(2017/06/13)
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- Omega-functionalized fatty acids, alcohols, and ethers via olefin metathesis
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Methyl 17-hydroxy stearate was converted to methyl octadec-16-enoate using copper sulfate adsorbed on silica gel. This compound served as a useful substrate for the olefin metathesis reaction. As a result, several fatty acids with novel functional groups at the x-end were prepared: a glyceryl ether attached at the 18-carbon, an aromatic fatty acid from eugenol, and a ferrocenyl fatty acid. By employing the unsaturated fatty alcohol, other groups were introduced, namely the terminal fluoride, bromide, and iodide were prepared, as was a thiol derivative. The penultimate and omega olefins reported here should serve as building blocks that allow fatty acids to make a greater contribution to a range of emerging technological
- Zerkowski, Jonathan A.,Solaiman, Daniel K. Y.
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experimental part
p. 1325 - 1332
(2012/09/10)
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