Pilot-Scale Biobased Adipic Acid Synthesis from Glucaric Acid Using a Bifunctional Pd–K–ReOx/AC Catalyst

The sustainable production of adipic acid (AA), a key monomer for nylon-6,6, has gained increasing attention as an alternative to fossil-derived routes. This study presents a biobased strategy for the AA synthesis from glucose via glucaric acid (GA) using a bifunctional Pd–K–ReOx catalyst supported on activated carbon (AC). The catalyst facilitates the tandem deoxygenation of GA under mild aqueous-phase conditions, achieving an adipic acid yield of up to 99% under optimized conditions with minimal byproduct formation. Catalyst optimization showed that the synergistic interaction between Pd and K-ReOx sites is critical for enhancing activity and suppressing over-reduction. Notably, the catalytic system was successfully scaled up to a 50 L reactor, delivering an adipic acid yield of 82% and demonstrating consistent performance and stability over multiple cycles. This study represents one of the first pilot-scale demonstrations of AA production from renewable feedstocks using an integrated chemo-catalytic approach. The results indicate that this scalable, biobased process offers a promising green alternative to conventional nitric acid oxidation of cyclohexane, contributing to the decarbonization of nylon manufacturing. This study establishes a robust, green, and scalable route for biobased adipic acid production with strong potential for industrial application.