Design of an acidic sulfonated mesoporous carbon catalyst for the synthesis of butyl levulinate from levulinic acid

Abstract

AbstractIn this work, the ordered mesoporous carbon CMK‐8 which has some advantages, including large specific pore volume, high surface area, and also its tunable pore size, was synthesized, then functionalized with various sulfonic acid groups and utilized as a heterogeneous catalyst in the esterification reaction of levulinic acid (LA) into n‐butyl levulinate (BL). The prepared catalysts were characterized using Fourier transformed‐infrared spectroscopy, N2 adsorption–desorption, small‐angle X‐ray diffraction analysis, elemental analysis, transmission electron microscopy, field emission scanning electron microscope, thermal gravimetric analysis, energy dispersive X‐ray spectroscopy, and elemental mapping. The important parameters such as reaction temperature, reaction time, catalyst amount, and LA to n‐BuOH molar ratio were investigated by Taguchi experimental design. Maximum BL yield (75.1%) and LA conversion (95%) were obtained with CMK‐8‐SO3H catalyst under optimum reaction conditions: reaction temperature 130°C, reaction time 10 h, catalyst dosage 0.015 g, and LA to n‐BuOH molar ratio 1:10. Among the entire parameters, LA to n‐BuOH molar ratio followed by the reaction temperature, catalyst concentration, and reaction time have the most influence on BL yield. Finally, the regeneration and reusability of the CMK‐8‐SO3H catalyst were studied, and the recovered catalyst showed high stability and activity after four runs.