Hydrogenation of ethylene carbonate catalyzed by lutidine-bridged N-heterocyclic carbene ligands and ruthenium precursors

A series of air and moisture-stable lutidine-bridged N-heterocyclic carbene (NHC) ligands and commercial Ru precursors were applied as catalysts for hydrogenation of ethylene carbonate to glycol and methanol. N-Butyl-substituted CNC-pincer ligand L1 and RuHCl(CO)(PPh₃)₃ catalytic system exhibited the highest catalytic activity with 99% conversion of ethylene carbonate, 92% glycol and 42% methanol yields. The high catalytic activity was attributed to the in-situ formation of Ru-NHC complexes in the presence of base. This facile, stable and efficient catalytic system provided a new method for the indirect conversion of CO₂.