Heparin/UiO-66 nanocomposite: Synergistic catalytic Lewis and Brønsted acids for efficient monosaccharides conversion to 5-hydroxymethylfurfural.

A new bio-based catalyst was fabricated by synthesizing a zirconium(III) (Zr)-based metal-organic framework, UiO-66, in the presence of natural sulfonic acid, heparin (Hep) oligosaccharide. Various characterization techniques were utilized to validate the successful synthesis of the nanocomposite, Hep/UiO-66. The catalytic efficiency of the resulting nanocomposite was assessed in the acid-catalyzed conversion of mono-saccharides (fructose and glucose) to 5-hydroxymethylfurfural (HMF). Optimization of reaction variables using Response Surface Method revealed that using 34 % of the catalyst at 100 and 110 °C for 30 and 50 min led to high yields of 98.5 % and 96.5 % for fructose and glucose conversion to HMF, respectively. The catalyst showed good recyclability, sustaining its productivity over 4 cycles. Comparative analyses with pristine Hep and UiO-66 indicated the superior performance of the catalyst, highlighting the synergistic effect between the Lewis and Brønsted acids originating from UiO-66 and Hep on the catalytic activity.