Investigation of Catalytic Sustainability of Silica-Based Mesoporous Acidic Catalysts and Ion-Exchange Resins in Methyl Acetate Synthesis and Characterizations of Synthesized Catalysts

Abstract

Silica-based materials functionalized with silicotungstic acid (STA) are shown as effective catalysts for methyl acetate reactions. In this work, hydrothermal and dry impregnation methods were used for the synthesis of STA/MCM-41 and STA/SBA-15 catalysts. MCM-41, SBA-15 and STA were utilized as silica sources and active material, respectively. The active compound was loaded using dry impregnation method after silica source, and the molar ratio of catalysts was determined as 10% tungsten/silicate (W/Si). The catalytic activities of STA/MCM-41, STA/SBA-15, Amberlite-35 and Amberlyst IR-120 catalysts were investigated with methyl acetate reactions. These experiments were repeated under the same conditions using recovered catalysts from the first reaction. It has been observed that the sustained activity of the synthesized catalysts after the second reactions is achieved for both 6- and 24-h analysis (6h: 10-19% and 24h: 23-35%). Although Amberlite-35 and Amberlyst IR-120 catalysts reached catalytic equilibrium at the end of 6h, catalytic activities of STA/MCM-41 and STA/SBA-15 catalysts continued to increase during the reactions. The physical characterization of the catalysts was determined by XRD, DRIFT, BET, SEM and MAPPING analysis methods.