Biobased Polyesters from Limonene Oxide and Anhydrides

The development of polymer materials derived from renewable resources for replacement of petroleum based ones is gaining growing interest both in industry and in the scientific research community 1,2. Terpenes represent a plentiful and inexpensive class of non-polar substrates with enormous potential for the synthesis of bio-based polymeric materials and limonene is the most common terpene. Limonene oils are industrially obtained as a by-product of citric fruit juice processing and are then oxidized to form mono- as well as difunctional epoxides. (R)-limonene oxide (LO), thanks to several features such as low cost, abundance, and structural similarity to cyclohexene oxide (CHO), represents an excellent choice as a bio-renewable epoxide monomer for copolymerization with anhydrides. Here we present the synthesis of alternating polyesters through reaction of phthalic and maleic anhydrides with LO and CHO by using salen metal complexes, with different cocatalysts, under various reaction conditions by Ring Opening COpolymerization (ROCOP).