Di(2-ethylhexyl) adipate (DEHA), A NEW HOPE! A sustainable and promising process for the plasticisers industry

Abstract

Plasticisers are commonly incorporated in plastic materials in order to improve their physico-chemicals properties. In particular, Poly-(vinyl chloride) (PVC) is a polymer which has excellent plasticiser compatibility characteristics. The demand for plasticized-PVC is steadily increasing and its synthesis need to be more sustainable, considering the interest in developing a circular economy in the next years. In order to achieve these goals, a bio-based process to synthesize di(2-ethylhexyl) adipate (DEHA), a widely used plasticiser, could be an interesting approach. The most important starting material for the process is adipic acid, but its synthesis from petrochemical sources is not sustainable. An alternative is using waste materials as substrates for fermentation in a totally green process. Among many strategies, the reverse adipate degradation pathway (RADP) in E. coli seems to be the most interesting one, considering the highest titer of 68 g/L and the yield of 93.1%. The next step is the enzyme-catalysed esterification of adipic acid and 2-ethylhexanol to produce DEHA, using an immobilized lipase from Candida antarctica. Applying a solvent-free system under vacuum condition is convenient as it guarantees a conversion to DEHA of 100 mol%.