Efficient catalytic production of levulinic acid over hydrothermally stable propyl sulfonic acid functionalized SBA-15 in γ-valerolactone-water system

To eco-friendly catalyze glucose to levulinic acid, recyclable acid catalyst has been researched. The synthesis process of propyl sulfonic acid functionalized SBA-15 was improved and the hydrophobic treatment was performed. The structure and functional groups of materials were characterized by X-ray diffraction, transmission electron microscopy, N-2 adsorption-desorption isotherms, elemental analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and simultaneous thermal analysis. The catalytic activity, recyclability and hydrothermal stability of CH3-SBA-15-SO3H material were researched. The highest yield of levulinic acid at 61.56% was obtained at 180 degrees C for 2.5 h in gamma-GVL-water solvent system, and the yield of levulinic acid was only decreased by 2% after 4 times reuse. The high degree of silicon polycondension and hydrophobic surface of CH3-SBA-15-SO3H were the key to maintain the hydrothermal stability. The CH3-SBA-15-SO3H solid acid had great potential in development and utilization of biomass resources.