Synthesis of Ethylene Glycol from Syngas via Oxidative Double Carbonylation of Ethanol to Diethyl Oxalate and Its Subsequent Hydrogenation

This work reports a novel sustainable two-step method for the synthesis of ethylene glycol (EG) using syngas. In the first step, diethyl oxalate was selectively synthesized via oxidative double carbonylation of ethanol and carbon monoxide (CO) using a ligand-free, recyclable Pd/C catalyst. In the second step, the diethyl oxalate produced underwent subsequent hydrogenation using [2-(di-tert-butylphosphinomethyl)-6-(diethylaminomethyl)pyridine]ruthenium(II) chlorocarbonyl hydride to get EG and ethanol. Thus, the generated ethanol can be recycled back to the first step for double carbonylation. This method gives a sustainable route to manufacture EG using carbon monoxide and hydrogen.