HYDRATION OF PROPENE OVER PROTON-EXCHANGED AND METAL ION-EXCHANGED ZEOLITE CATALYSTS AT ATMOSPHERIC-PRESSURE

The gas-phase hydration of propene over proton-exchanged or metal ion-exchanged zeolites with various Si/Al ratios and structures (such as ZSM-5, mordenite, ferrierite, and Y-type) has been studied. It was found that the catalytic activity of proton-exchanged zeolites for the conversion of propene to 2-propanol did not depend on their framework structure, but showed a volcano-shaped dependence on the Al content, as was observed in the hydration of ethene. On the basis of temperature-programmed desorption experiments of NH3 adsorbed on the zeolites, it was confirmed that the activity is controlled by the acidity of the catalysts. The catalytic activity of metal ion-exchanged Y zeolites increased with an increase in the electronegativity of the metal ion.