Propylene carbonate synthesis routes using CO2: DFT and thermodynamic analysis

Abstract

Propylene carbonate (PC) is utilized to improve performance and stability in lithium-ion batteries as an electrolyte component and as a high-performance solvent in paints, varnishes, and adhesives. It is a versatile chemical used in many different industries. It also functions as a plasticizer in polymers and a solvent in pharmaceutical and cosmetic formulations. In the current work, chemical equilibrium analyses of a number of potential processes involved in the synthesis of PC were conducted. To examine the thermodynamic viability of all five approaches, the fluctuation of $\Delta G_m^o$ with temperature for the key processes of PC synthesis was investigated in a specific temperature range of 25 °C-180 °C and at 1 bar and 60 bar pressures. The heat capacity values were estimated using the Rozicka-Domalski method. Benson Group-Increment Theory (BGIT) was used to evaluate the unknown ${\Delta }_{f}H$ for a molecule. By examining the impact of temperature (25 °C-180 °C) and pressure (0–100 bars) on chemical equilibrium constant and equilibrium conversion of reactants, the main reactions of PC synthesis pathways were compared. It was discovered that the one-pot synthesis route and the o-chloropropanol and CO₂ approach were superior. The DFT calculations were performed to study the energy changes taking place to convert propylene, glycerol, and propylene glycol (PG) into PC. Both thermodynamic and DFT calculations proved that the PG and urea route is the least favorable for synthesizing PC.