Catalytic production of 5-hydroxymethylfurfural from lignocellulosic biomass: Recent advances, challenges and opportunities

Lignocellulosic biomass is the only renewable source of organic carbon, presenting a sustainable alternative to fossil fuels in the green production of value-added chemicals, transportation fuels, and polymeric materials. The process for converting biomass into desired end-products typically involves multiple steps through the formation of intermediate molecules or "platform chemicals". One such pivotal platform chemical is 5-hydroxymethylfurfural (HMF). Therefore, the efficient and selective conversion of biomass into HMF emerges as an imperative research focus. This review highlights the latest breakthroughs in the catalytic production of HMF from biomass and derivative sugars. An in-depth exploration of various synthesis pathways for HMF is provided, shedding light on the critical roles played by raw materials, catalysts, solvents, and operating conditions in influencing reaction performance. Central to the discussion is elucidating the mechanisms and active sites involved in HMF synthesis, with a spotlight on the synergy effects of Lewis acid and Brønsted sites within catalysts during the hydrolysis, isomerization, and dehydration phases of HMF production. The pivotal step of isomerization, which determines the reaction rate in HMF synthesis from biomass, is given particular attention. In conclusion, the review reflects on the state-of-the-art progress and charts out prospective avenues for enhancing HMF production from biomass. Through this, our ultimate aim is to guide future innovations in catalytic systems for HMF synthesis from biomass, fostering their swift transition into industrial applications.