SOLVOTHERMAL SYNTHESIS AND CHARACTERIZATION OF TEREPHTHALIC ACID-BASED METAL-ORGANIC FRAMEWORKS AND THEIR CATALYTIC APPLICATION IN BIODIESEL PRODUCTION

Abstract

Metal-Organic Frameworks (MOFs) are a class of porous crystalline materials, consisting of metal ions or nodes linked with organic ligands. The study was aimed at solvothermal synthesis and characterization of terephthalic acid-based Metal-Organic Frameworks and their catalytic application in biodiesel production. Three MOFs of Cu-, Fe-, and Cr-based were solvothermally synthesized, characterized and applied as catalysts in biodiesel production using ethanol and oil extracted from Yellow Oleander seeds. The MOFs were synthesized using terephthalic acid as the linker and copper (II), iron (III) and chromium (III) nitrates as metal ion sources. Each of the synthesized MOFs showed high melting point exceeding 360 oC. Microscopic view and powder X- ray diffraction analysis indicated Cu-MOF to be crystalline with numerous sharp peaks while those for Fe- and Cr-MOFs were amorphous. A comparison of the FT-IR spectra of the ligand and those of the MOFs confirmed the presence of the ligand in the synthesized MOFs. In the absence of a catalyst, the transesterification was not achieved. However, in the presence of the more crystalline Cu-MOF as catalyst resulted to high yield (83.33%) and in a shorter time compared to the less crystalline Fe- (33.33%) and Cr- (25.00%) MOFs. Thus, catalytic ability of the MOFs were in the order: Cu-MOF > Fe-MOF > Cr-MOF. Hence MOFs especially Cu-MOFs can be applied as catalyst in biodiesel production. Further studies and characterization (single X-ray diffraction) should be done for proper elucidation of the crystal structure of the MOFs.