Synthesis of UiO-66-SO3H-Cl as the recyclable multifunctional catalyst for efficient conversion of glucose to 5–Hydroxymethylfurfural

5-Hydroxymethylfurfural (HMF), a leading platform combination for altering biomass to diverse biomass-derived chemicals and biofuels, has been engrossed in spacious consideration. In this perusal, a new catalyst modified with sulfonic acid and -Cl functional group UiO-66-SO₃H-Cl was first used as an efficiently heterogeneous catalyst with the overlapping effect of three functional groups of Lewis acid, Brønsted acid and -Cl group binding site was synthesized to convert glucose to HMF. The Lewis acid site is responsible for the isomerization of glucose to fructose, and the dehydration of fructose to HMF is the responsibility of the Brønsted acid site. The -Cl group facilitates the hydrolysis of glucose by forming a hydrogen bond with glucose and reducing the activation energy, thus increasing the production rate of HMF. The synthesized catalysts were analyzed using XRD, FT-IR, FE-SEM, EDS, and XPS. The amount of Zr, Cl, and S elements reported in the newly synthesized catalyst in this research by EDS is 37.44%, 1.01%, and 6.8%, respectively. The existence of C 1s (284.8 eV), O 1s (531.9 eV), Cl 2p (200.4 eV), Zr 3d (185.2 eV), and S 2p (168.4 eV) of UiO-66-SO3H-Cl was confirmed by conducting XPS analysis. The reaction range of 5-HMF produced from glucose by each of UiO-66, UiO-66-SO₃H, and UiO-66-SO₃H-Cl catalysts, was 10%, 23% and 74%, respectively, as determined by UV-Vis analysis was decided the results show that the UiO-66-SO₃H-Cl catalyst with three functional groups synergistically increases the production of HMF from glucose.

Graphical Abstract

Conversion of glucose to HMF by UiO-66-SO₃H-Cl multifunctional solid catalyst: Lewis acid (Zr cation) and Brønsted acid (SO₃H group) are active sites for isomerizing glucose to fructose and dehydration of fructose to HMF, respectively. The -Cl group forms a hydrogen bond with glucose, increasing the production rate of HMF.