5-Hydroxymethylfurfural Hydrodeoxygenation Coupled with Water-Gas Shift Reaction for 2,5-Dimethylfuran Production over Au/ZrO<sub>2</sub> Catalysts
Zhijian Li, Changhui Zhu, Haiyong Wang, Yuan Liang, Haosheng Xin, Song Li, Xiaohong Hu, Chenguang Wang, Qi Zhang, Qiying Liu, Longlong Ma
Abstract
For the biomass catalytic valorization in the presence of a H2 atmosphere, large amounts of H2O and H2 are necessary to improve the processing efficiency, which resulted in the waste of such generous inputs. As a model reaction, the traditional hydrodeoxygenation of 5-hydroxymethylfurfural (5-HMF) selectively produces 2,5-dimethylfuran (2,5-DMF) under high pressure H2. Meanwhile, the water-gas shift reaction (WGSR) can counteract the harmful CO by simultaneously producing H2 from H2O. The hydrogenolysis of 5-HMF to 2,5-DMF produces H2O because of the hydroxyl group removal. Therefore, adding a trace amount of H2O to initiate 5-HMF hydrodeoxygenation coupled with WGSR to achieve H2O recycling in the reaction process is of great significance but extremely challenging. Herein, we reported a new process for the selective hydrodeoxygenation of 5-HMF to 2,5-DMF coupled with WGSR using a single catalyst, Au/ZrO2. A detailed study showed that the hydrogen species produced in situ by WGSR was used for 5-HMF hydrodeoxygenation to obtain 78.5% of 2,5-DMF yield. The H/H2O cycle in the coupling reactions exhibited a H2 utilization efficiency of 88.2%. Without using external H2, this work provided a new method for 5-HMF hydrodeoxygenation to 2,5-DMF triggered by WGSR and also showed the potential for application in H2O-saving conversion of cellulosic biomass with C–OH or C═O groups to value-added chemicals and fuels.