ENHANCEMENT OF ACIDITY AND CATALYTIC ACTIVITY OF ALUMINA BASED METAL ORGANIC FRAMEWORK (MIL-53 Al)

Abstract

Metal organic frameworks are highly porous materials which are formed bycombination of metal precursor and salts as inorganic part and ligand asorganic part. They have many advantages such as low density, high surface area,tunable pore size and high porosity. Due to peculiar features, such asunsaturated metal active sites, high surface area and easily functionalization,its usage as catalyst are promising.  The MIL-53(Al) structure contains chains of transcorner-sharing [AlO4(OH)2] octahedra that are connectedto each other by 1,4 benzenedicarboxylate (BDC) ligands, and thus 3D net inwhich one-dimensional channels run parallel to the inorganic backbone of thestructure is formed. There are so many studied onusage of aluminium based metal organic framework in adsorption and gasadsorption and separation processes. However, there is very limited number ofstudies on catalytic properties of this material.  MIL-53(Al) provides several advantages compared withother MOFs such as high thermal stability, cheap, and available raw materials.It is also moisture resistant and has relatively high surface area which makesit an attractive MOF alternative for catalytic processes. In this study,aluminium salt was selected as metal precursor and MIL-53 (Al) was synthesizedby solvothermal method.  Then the synthesized material was sulfated to increasethe acidity. The characterization of synthesized and sulfated materials wereperformed by FT-IR, BET, XRD and TGA methods. The catalytic activity ofsulfated material was tested in esterification reaction of acetic acid. Theeffects of time, sulfation, temperature and alcohol type were investigated.