Pt–Sb Bimetallic Catalysts for Base-Free Aerobic Oxidation of Diethylene Glycol to Diglycolic Acid

Abstract

Diglycolic acid (DGA) has emerged as a promising feedstock for the synthesis of biomass-derived platform molecules, yet its high cost remains a major barrier to practical implementation. Hence, we developed a series of PtSb/CeO2 catalysts for the selective oxidation of diethylene glycol (DEG) to value-added DGA. Under mild conditions, Pt2Sb3/CeO2 delivered DGA in 90.0% yield using molecular oxygen (O2) as the oxidant and water (H2O) as the solvent. This excellent catalytic performance is likely attributed to the formation of the ultrafine Pt–Sb nanoparticles (1.8 ± 0.7 nm) and the increased oxygen vacancy concentration, which provides more active sites for DEG oxidation. Concurrently, the high 88.7% DGA yield achieved at an elevated DEG concentration (0.4 M) significantly reduced solvent demand and downstream separation energy costs, while simultaneously enabling gram-scale DGA production in a single reaction. Also, the catalyst exhibited excellent robustness and could be recycled up to eight cycles while maintaining a DGA yield of 86.1–90.0%, indicating the excellent sustainability of the reaction system. Furthermore, preliminary techno-economic analysis demonstrated the promising economic feasibility of this system. Moreover, its effectiveness in the transformation of a range of polyols highlights its potential as a sustainable and atom-economical platform for the green synthesis of value-added dicarboxylic acids.