Effects of Reoxidation and Water Vapor on Selective Partial Oxidation of Propylene to Acrolein in Copper(II)-Exchanged X and Y Zeolites

Article abstract of DOI:10.1021/j100170a049

The effects of reoxidation and water vapor on the selective partial oxidation of propylene to acrolein over Cu(II)-exchanged X and Y zeolites were examined as a function of the oxygen-to-propylene mole ratio in a flow system at 350 deg C.The catalytic activity and the reduction of cupric ion species during reaction were studied by gas chromatography and electron spin resonance spectroscopy.The effects of both reoxidation and water vapor introduction resulted in a selective increase of acrolein formation during reaction.The cupric ion intensity in the zeolite decreases during propylene oxidation at low oxygen-to-propylene mole ratios.Reoxidation after propylene oxidation is suggested to increase the formation of copper oxides, CuO and Cu2O, in the zeolite framework.Cuprous oxide formed during the reaction is suggested to be an active species for the partial oxidation of propylene to acrolein.The introduction of water vapor decreases Cu(II) reduction and decreases coke formation in the zeolite; this decreases catalyst deactivation during reaction.After introduction of water vapor, cuprous ion in an exchange site and cuprous oxide are suggested to be active for acrolein formation.