Syntesis and characterization of different catalysts for industrial dotp (dioctylterephthalate) production

Today, the global plasticizer market has exceeded 10 million tons, with 90% of this production directed towards flexible PVC materials. However, homogeneous esterification reactions used in traditional production processes possess significant disadvantages, such as long reaction times (4-5 hours), high energy costs, and wastewater pollution resulting from the removal of harmful metal catalysts. In this study, to overcome these environmental and economic challenges, Metal-Organic Framework (MOF) structures were synthesized and utilized as heterogeneous catalysts. Within the scope of the study, MOF synthesis was carried out via solvothermal and conventional methods using titanium (IV) isopropoxide with terephthalic acid and 2-aminoterephthalic acid ligands. It was determined that these synthesized catalysts exhibited superior catalytic performance with a 99% yield in the production of Di(2-ethylhexyl) terephthalate (DOTP) at 190 °C in a short duration of only 1.0 hour. Furthermore, these MOF structures were found to offer high efficiency and recyclability in the synthesis of other significant plasticizers such as DOP, TOTM, DOA, and DOS. Owing to the dominant role of the titanium metal nodes of the MOFs in the esterification reaction and the positive impact of the functional groups in the ligands, an environmentally friendly and economic alternative for industrial production was presented.