Dehydration of glucose to 5-hydroxymethylfurfural by a core-shell Fe3O4@SiO2-SO3H magnetic nanoparticle catalyst

In this paper we discuss the potential use of (Fe3O4@SiO2-SO3H) nanoparticle catalyst for the dehydration of glucose into 5-hydroxymethylfurfural (HMF). A magnetically recoverable (Fe3O4@SiO2-SO3H) nanoparticle catalyst was successfully prepared by supporting sulfonic acid groups (SO3H) on the surface of silica-coated Fe3O4 nanoparticles. The prepared catalyst was characterized by FTIR, TGA, XRD, HRTEM-EDX, and N-2 adsorption-desorption isothermal analyses. The catalyst's surface acidity was determined by acid-base titration. Dehydration of glucose was performed in a biphasic system made up of water and methylisobutylketone (water/MIBK), and the effect of various reaction parameters affecting on the yield of HMF such as biphasic system ratio, catalyst concentration, temperature, time, and dimethylsulfoxide (DMSO) ratio were studied. Fe3O4@SiO2-SO3H catalyst disclosed a great catalytic activity for the formation of HMF and glucose conversion. About 70% yield of HMF and 98% glucose conversion were obtained at the optimum reaction conditions (40% catalyst concentration, 140 degrees C, 24 h and biphasic system of 1: 4 (water: MIBK) ratio). At the end of the reaction, the catalyst was easily removed from the reaction mixture using a magnet and reused several times without high loss in catalytic activity.