A renewable bisepoxide, SYR-EPO, was prepared from syringaresinol, a naturally occurring bisphenol deriving from sinapic acid, by using a chemo-enzymatic synthetic pathway. Estrogenic activity tests revealed no endocrine disruption for syringaresinol. Its glycidylation afforded SYR-EPO with excellent yield and purity. This biobased, safe epoxy precursor was then cured with conventional and renewable diamines for the preparation of epoxy-amine resins. The resulting thermosets were thermally and mechanically characterized. Thermal analyses of these new resins showed excellent thermal stabilities (T =279-309 °C) and T ranging from 73 to 126 °C, almost reaching the properties of those obtained with the diglycidylether of bisphenol A (DGEBA), extensively used in the polymer industry (T =319 °C and T =150 °C for DGEBA/isophorone diamine resins). Degradation studies in NaOH and HCl aqueous solutions also highlighted the robustness of the syringaresinol-based resins, similar to bisphenol A (BPA). All these results undoubtedly confirmed the potential of syringaresinol as a greener and safer substitute for BPA.

We report herein an optimized biocatalytic oxidative process for the synthesis of syringaresinol from sinapyl alcohol at a multigram scale (93% yield) in very high yield. Syringaresinol thereby obtained is of sufficient chemical purity and exhibits good thermal and antiradical activities to be used without further purification in many applications related to polymer syn-thesis as an alternative to bisphenol A. Different mechanistic pathways were discussed to better understand the impact of reaction conditions on the type of linkage formed during the oxidative process. Antiradical activity (DPPH analysis) and thermal properties of syringaresinol are also discussed.[a] A.