Monomers and their polymers derived from saturated fatty acid methyl esters and dimethyl carbonate

Abstract

In this study, we exploit the alpha-acidity of saturated fatty acid methyl esters (FAMEs) for the direct conversion of these renewable raw materials to malonate derivatives. After deprotonation with sodium hydride in dimethyl carbonate (DMC) as reactive solvent, the ester enolates react with DMC to give the desired products with up to 80% isolated yield. These malonate derivatives, bearing a long aliphatic chain with chain lengths of C₆–C₁₆, were then polymerized to yield polyesters and polyamides. The polyesters were obtained by copolymerization with 1,6-hexanediol and titanium isopropoxide as a catalyst. For the polyamides, 1,6-hexanediamine was used with 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as a catalyst. The obtained polyesters are highly viscous and tacky materials with low melting points and a molecular weight range of 9–17 kDa. The polyamides, on the other hand, are high melting polymers with molecular weights from 7–15 kDa.