Dengfeng Dai,Chao Feng,Minmin Wang,Qingzhou Du,Dandan Liu,Yuan Pan,Yunqi Liu
Biomass-based chemicals as a renewable alternative to petroleum-based chemicals are of great significance. The conversion of biomass-based furfuryl alcohol to pentanediol, including 1,5-pentanediol and 1,2-pentanediol, is explored over a series of bifunctional Cu/MFI catalysts in a continuous-flow reactor. These catalysts are synthesized by supporting copper nanoparticles on MFI zeolites with varying molar ratios of SiO2/Al2O3. Among them, the Z60-10Cu catalyst containing balanced Cu0–Cu+ and Brønsted acid sites exhibits excellent performance, and a high furfuryl alcohol conversion of 99.5% and selectivity of 85.2% for 1,5-pentanediol (69.2%) and 1,2-pentanediol (16.0%) could be achieved (hydrogen pressure: 2.5 MPa) at 160 °C. The experimental results and the results obtained using the DFT technique revealed that the high catalytic activity realized during the processes of ring-opening and hydrogenation could be attributed to the synergistic effect between the Cu species and Brønsted acid sites. The Brønsted acid sites on the Si(OH)Al groups significantly affect the ring-opening process of furfuryl alcohol. The methoxy group on furfuryl alcohol adsorbs on the Cu+ sites, and the hydrogenation saturation of the ring-opening intermediate is realized under the influence of the activated hydrogen units on the Cu0 sites. The results reported herein could help promote the continuous production of high value-added pentanediol from biomass-based raw materials in the presence of non-noble metal catalysts. An economical and feasible path for the transformation of biomass resources into high value-added fine chemicals could also be developed.
Transition-state shape selectivity plays a crucial role in catalytic systems where reactants and products exhibit comparable molecular dimensions, as it restricts the accessible configuration space of reaction intermediates. Herein, we designed a Cu@MFI catalyst by encapsulating Cu active sites within the well-defined micropores of MFI zeolite through a pore confinement strategy. This architecture preserves the zeolite framework integrity while maintaining unhindered internal mass transport, thereby enabling precise spatial control over transition-state configurations. Employing furfural hydrogenation as a probe reaction, the metal-zeolite synergy in Cu@MFI endowed the catalyst with exceptional activity (100% furfural conversion) and quantitative selectivity (100% furfuryl alcohol) at 70 °C, sustained across a broad temperature window. Mechanistic studies reveal that the transition-state shape selectivity effectively prevented H 2 O interaction with the furan ring, offering valuable insights for other reaction systems seeking to exploit shape selectivity for specific transformations.