Study On The Preparation Of MCM-41Catalyst And Its Application For Production5-HMF Dehydration From Fructose

MCM-41has a wide range of applications in adsorption separation, catalytic of petroleum processing and biological macromolecules due to the regular pore structure, uniform and adjustable pore size, large specific surface area. However, compared with the traditional zeolites, the acidity and hydrothermal stability of MCM-41are relatively low, which severely limit their practical applications in industry. Therefore, it is of great interest how to improve its structure, hydrothermal stability and acidity of MCM-41materials in recent years.In this work, a series of different Si/Al molar ratio of MCM-41have been synthesized by using CTAB as structural template, sodium silicate as silica source and sodium aluminate as aluminum source under alkaline medium with secondary restructure method. X-ray diffraction, N2adsorption, SEM, and FT-IR were used to characterize the properties of MCM-41. The results showed that the samples have a hexagonal mesoporous structure, a pore diameter of3.6nm, a BET surface area of larger than800m2·g-1and a pore volume of larger than0.7cm3·g-1.The results of testing the hydrothermal stability of the MCM-41using XRD show that both the secondary restructure and the introduction of Al atom into the framework can improve the hydrothermal stability of MCM-41obviously, The mesoporous structure, specific surface area and pore size can be maintained after hydrothermal stability test in boiling water more than12h. Furthermore, MCM-41with Si/Al=25via secondary restructure has the optimal hydrothermal stability.The catalytic reaction of MCM-41prepared is evaluated by dehydrating fructose for5-hydroxylmethylfurfural (5-HMF), using MCM-41with Si/Al=25as catalyst, two-phase system of water-MIBK as solvent. It is found that the MCM-41can improve the yield of5-HMF significantly. By designing single factor experiments, the optimal conditions are as follow:the reaction temperature is170℃,reaction time is75min, the mass ratio of glucose to MCM-41is40:1, the concentration of glucose is8%, the volume ratio of water to MIBK is4:1. Under these conditions, the maximum yield of5-HMF is64.25%.