Synthesis of diethyl carbonate from ethanol and CO2 over ZrO2 catalysts

Abstract

Diethyl carbonate (DEC) is a versatile chemical with several commercial uses. The synthesis of DEC from carbon dioxide and ethanol is both environmentally friendly and can be integrated into the ethanol biorefinery. A thermodynamic evaluation was made to predict the amount of DEC produced at equilibrium at the reaction conditions used in this work. Zirconium oxide solids were prepared using sol–gel methodology and were loaded with Na, Mg or PO4−3 using the incipient wetness impregnation method. Catalytic tests were carried out in a 500 mL stainless steel Parr reactor at 423 K. The DEC yield decreased as the Na or Mg load increased, while increasing the yield of acetaldehyde. However, DEC yield and selectivity increased as the PO4−3 load increased, while the acetaldehyde yield decreased. Lower overall acid site density and lower than 2.8 µmol-CO2/m2 basic site density resulted in a higher DEC yield.