Aqueous Phase Synthesis of 5-Hydroxymethylfurfuralfrom Glucose over Large Pore Mesoporous Zirconium Phosphates: Effectof Calcination Temperature

摘要

For a solid acid-catalyzed dehydration of biomass-derived carbohydrates into useful furan derivatives, a suitable porous solid acid catalyst having an optimum acidic density and its strength is required to avoid cascade reactions in biomass conversion processes. A large-pore mesoporous zirconium phosphate (m-ZrP) was prepared hydrothermally using P123 as a template in water solvent, which resulted in a higher pore diameter (>9 nm) having wormhole-like pore structures with balanced Lewis (L) to Brönsted (B) acid sites. The effects of calcination temperature (500–800 °C) on the textural, acidic/basic, and structural properties of the m-ZrP with its catalytic performance for glucose dehydration to 5-hydroxymethylfurfural (HMF) were investigated in a pure water media as a green and sustainable alternative solvent. The larger number of L and B acid sites and basic sites with their appropriate strengths were clearly related with a better catalytic performance in terms of glucose conversion and HMFyield. The strong L acid and basic sites in the m-ZrP efficiently promoted the glucose isomerization to fructose,which dehydrated exclusively on the weak B acid sites resulting ina maximum conversion of glucose (83.8%) and HMF yield (46.6%). Theadjusted acidic and basic sites with large mesopore sizes make the m-ZrP yield a higher reaction rate (2.78 mmol gcat^–1 h^–1) and turnover frequency(11.68/h) for conversion of glucose to HMF, which showed higher catalyticactivity than those of a small-pore m-ZrP and othermesoporous heterogeneous and homogeneous acid catalysts.