Aliphatic Long-Chain C20 Polyesters from Olefin Metathesis

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Abstract

Self-metathesis of undecenoic acid with [(PCy3)2Cl2Ru[DOUBLE BOND]CHPh] (2), followed by exhaustive hydrogenation yielded pure 1,20-eicosanedioic acid (5) (>99%) free of side-products from isomerization. Polycondensation with eicosane-1,20-diol (6), formed by reduction of the diol, yielded polyester 20,20 (Tm = 108 °C). By comparison, the known ADMET polymerization of undec-10-enyl undec-10-enoate (7), and subsequent exhaustive polymer-analogous hydrogenation yielded a polyester (poly-8) with irregular structure of the ester groups in the polymer chain ([BOND]O(C[DOUBLE BOND]O)[BOND] vs. [BOND]C([DOUBLE BOND]O)O[BOND]) (Tm = 103 °C). Hydrogenation of secondary dispersions of poly-7 yielded aqueous dispersions of the long-chain aliphatic polyester poly-8.

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