Dehydration of propan-2-ol on X zeolites

Abstract

The dehydration of propan-2-ol on moderately protonated X zeolites leads to the formation of both propene and di-isopropyl ether at temperatures in the range 383–430 K. Unexchanged zeolite was considerably less active, and only yielded propene at temperatures in the range 444–450 K. With protonated X zeolites the rates of formation of both products were investigated as a function of temperature, pressure of propan-2-ol and the extent of protonation, which lay between 8.6 and 28.4%. Decomposition at 411 K was completely poisoned by pyridine vapour. The Brønsted acidity of the accessible hydroxyl groups within the zeolites is considered to be the source of activity, and a mechanism involving carbonium and oxonium ions is proposed.