Thermoplastic Polyesters from Plant Oils by Carbonylation Chemistry

Thermoplastic polyesters are currently prepared almost exclusively from fossil feedstocks. In view of an ever increasing demand for fossil fuels and their limited range a more efficient utilisation of the renewable substrate and the exploitation of other sources is an attractive long term challenge.
We report a carbonylation polymerisation route to prepare aliphatic polyester based on castor oil, a readily available plant seed oil. The major component of castor oil is ricinoleic acid, which is converted in two high conversion steps to the ω unsaturated alcohol undec-10-en-1-ol.
Alkoxycarbonylation, resembling an AB step growth polymerisation, was utilised for the synthesis of poly(dodecanoate by exposing neat undec-10-en-1-ol to carbon monoxide pressure at elevated temperature in the presence of catalytic amounts of d8-metal catalysts. Higher molecular weight semi crystalline polymer with Mn > 10 000 g/mol was obtained. A control of polymer microstructure and thus thermal properties via the catalyst is addressed. In this entirely chemical polyester synthesis, not involving fermentation, the molecular structure of the plant oil feedstock is largely retained in the polyester product.