Abstract The use of organic chemicals derived from renewable sources to synthesize functional solid materials for heterogeneous catalysis is of great significance. Herein, a new porous and acid-base bifunctional hybrid… Click to show full abstract
Abstract The use of organic chemicals derived from renewable sources to synthesize functional solid materials for heterogeneous catalysis is of great significance. Herein, a new porous and acid-base bifunctional hybrid (FDCA-Hf) was designed and prepared by simple assembly of biomass-derived 2,5-furandicarboxylic acid (FDCA) with hafnium (Hf) under template-free conditions. The resulting FDCA-Hf hybrid with mesopores centered at 6.9 nm, moderate surface area (365.8 m2/g) and acid-base couple sites (density: 0.51 vs 0.97 mmol/g, acid/base molar ratio: 0.53), could selectively catalyze the Meerwein-Ponndorf-Verley reduction of carbonyl compounds under mild reaction conditions (as low as 90 °C in a short time of 1 h), especially of ethyl levulinate to γ-valerolactone, in quantitative yields (95–100%) and relatively higher reaction rate (e.g., turnover frequency: 2.28 h−1) compared to other catalysts. Moreover, the efficient simultaneous (trans)esterification of Jatropha oils with high acidic values to biodiesel (up to 98% yield) could also be achieved over FDCA-Hf with robust acid-base catalytic sites. The FDCA-Hf hybrid was highly stable due to the presence of robust metal-organic framework and could be resued with no decline in activity. Further studies demonstrated that the synergistic role of Lewis acid-base couple species (Hf4+–O2−) and Bronsted acidic species ( OH) of FDCA-Hf contributed greatly to its pronounced catalytic activity.
               
Click one of the above tabs to view related content.