Catalytic conversion of cellulose to ethylene glycol using functionalized covalent organic frameworks

Abstract

The utilization of abundant and renewable cellulose as an alternative to fossil resources provides a promising pathway for the sustainable production of bio-based chemicals. The development of multifunctional catalysts is key to achieving the efficient conversion of cellulose into high value-added chemicals. In this study, a combination of in situ and post-synthetic strategies was employed to synthesize functionalized covalent organic frameworks (COFs). Using aldehyde monomers containing phenolic hydroxyl groups and amine monomers with triazine structure as raw materials, COFs (TATP) rich in acidic active sites were successfully synthesized via the solvothermal method. Subsequently, a multifunctional catalyst (Ru-WOx/TATP) capable of catalyzing hydrolysis, hydrogenolysis, and hydrogenation reactions was developed by loading active metals ruthenium (Ru) and tungsten (W). Finally, this catalyst was applied to the research on one-step catalytic conversion of cellulose to ethylene glycol (EG). The results showed that Ru-WOx/TATP exhibited good crystallinity and thermal stability, and showed excellent catalytic performance and high selectivity for EG in the one-pot aqueous-phase conversion of cellulose. Under the optimal reaction conditions of 245 °C, an initial hydrogen pressure of 5 MPa, a substrate concentration of 1%, and a reaction time of 3 h, complete cellulose conversion was achieved, with an ethylene glycol yield of up to 62.9%. This work innovatively developed a functionalized COF with catalytic capabilities for hydrolysis, hydrogenolysis, and hydrogenation, and applied it to the catalytic conversion of cellulose into EG, thereby expanding the application scope of COFs in biomass catalysis.