Selective and efficient oxidation of ethylene to ethylene glycol acetates with H2O2 catalyzed by Pd(OAc)2–di(2-pyridyl)ketone–di(2-pyridyl)methanesulfonate system

Novel systems for palladium-catalyzed selective oxidation of ethylene to a mixture of ethylene glycol mono- and di-acetates as the major reaction products (90–95% selectivity) with H2O2 in acetic acid solution at ambient pressure and 20 °C were developed. The catalytic reaction is very efficient with up to 90% combined yield of glycol acetates with H2O2 as a limiting reagent and 1 mol% catalyst loading. The catalytic systems developed are comprised of a mixture of Pd(OAc)2, and 6-methyl substituted (2-pyridyl)methanesulfonate and/or di(6-pyridyl)ketone ligands. Compositions of the binary, Pd(OAc)2–dpk, Pd(OAc)2–Me-dpms, and ternary, Pd(OAc)2–dpk–Me-dpms, systems have been studied by means of 1H NMR spectroscopy and ESI mass spectrometry. Kinetics studies were performed as well and plausible reaction mechanism was suggested, which features facially chelating ligand-enabled facile oxidation of PdIIC2H4OAc intermediates with H2O2 to form PdIVC2H4OAc transients.