Studying complex formation of zirconium in N,N dimethylformamide (DMF) [ZrO(OH)2.(DMF)] using DFT calculations to produce dimethyl carbonate via transesterification

Abstract

The transesterification reaction, for the synthesis of dimethyl carbonate (DMC) and propylene glycol (PG) from methanol and propylene carbonate, is a new and ecologically benign alternative to conventional methods such as phosgene methanolysis, urea methanolysis, electrochemical technique, and so forth. This research focuses on the possible complex structures produced by calcining zirconium salt with N,N-dimethylformamide (DMF) at different calcination temperatures (450, 550, 650, and 750°C) to make catalysts. The catalysts are classified as Z-450, Z-550, Z-650, and Z-750 based on their calcination temperature. The catalysts are then examined using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) to determine the reaction process. X-ray diffraction (XRD) examination is used to evaluate the crystallinity of the catalysts, while field emission scanning electron microscopy (FE-SEM) is utilized to study the morphology. The CO₂-TPD aids in determining basicity to investigate the active locations for interaction. The reaction takes place in a batch reactor at a constant temperature of 150–180°C and a molar ratio of 5–10 for methanol to PC. The oxygen vacancy concentrations, basicity, and structure of the catalyst created by the mixing of DMF with zirconium produce [ZrO(OH)₂.(DMF)] as simulated by DFT calculations improved the yield and selectivity of DMC. The Z-750 catalyst provided maximal PC conversion of 88% at 170°C with stirring speeds ranging from 600 to 650 rpm.