Multifunctional Tin-Based Heterogeneous Catalyst for Catalytic Conversion of Glucose to 5-Hydroxymethylfurfural

Using 5-sulfoisophthalic acid as the ligand, tin porous coordination polymer (SnPCP) was synthesized on polydopamine-coated MnO2 (MnO2–PDA). The novel composite SnPCP@MnO2–PDA was used for conversion of glucose into 5-hydroxymethylfurfural (HMF). The tetrahedral-coordinated tin and the sulfonic groups of the ligand catalyze glucose isomerization to fructose and fructose dehydration to HMF, respectively. Thus, the composite is a bifunctional catalyst. The porous structure of SnPCP of the composite facilitates the transport of glucose, intermediate, and HMF within the catalyst. In addition, MnO2–PDA was found to be able to catalyze the conversion of glucose to HMF. The synergistic effect of SnPCP and MnO2–PDA achieved HMF yields of 55.8% in DMSO and 41.2% in water/THF. Consecutive use of SnPCP@MnO2–PDA demonstrated that, after 5 cycles, the activity loss is not significant in terms of the HMF yield and glucose conversion.