Highly Efficient Production of 5‑Hydroxymethylfurfural from Fructose via a Bromine-Functionalized Porous Catalyst under Mild Conditions

Efficient 5-hydroxymethylfurfural (HMF) production remains challenging due to the limited tolerance of HMF to strong Brønsted acids. Herein, this work provides a new strategy for effective HMF production from fructose via purposefully constructing a halogen-functionalized heterogeneous catalyst. Specifically, a novel bromine-functionalized triazine-based porous organic polyurea network (TPU-Br) was prepared by a solvothermal synthesis of TPU and subsequent bromination. Catalytic results indicated that a 96.0% HMF yield with a 99.2% selectivity was obtained when using a low TPU-Br loading (4 wt %) at 120 °C for 1 h, showing its mild and efficient catalytic activity. Meanwhile, the TPU-Br exhibited HMF selectivity exceeding 93% for all tested conditions and four catalytic cycles, which is attributed to the fast departure of HMF on the hydrophilic catalytic sites in TPU-Br’s hydrophobic aromatic network. This study provides a new strategy for developing non-acidic porous catalysts for high-efficiency HMF production.