Synthesis of methyl tert-butyl ether on sulfur-promoted ZrO2

The synthesis of methyl tert-butyl ether (MTBE) from methanol and isobutylene in a gas-solid heterogeneous system over sulfur-promoted zirconias calcined at different temperatures between 400 and 700 degrees C was studied. The reaction temperature was varied in the range 90-110 degrees C, and methanol to isobutylene molar ratios were changed from 1.0 to 1.3. The catalyst acidity was a direct function of the sulfur load, in turn a consequence of the calcination temperature. Temperature programmed reduction experiments allowed us to observe that the sulfur reduction process is different according to the calcination temperature. The highest activity was observed on the sample calcined at 600 degrees C, which was comparable with that of the reference catalyst Amberlyst 15 under the same conditions. A direct relationship between catalyst acidity and conversion was not observed. The injection of water completely poisoned the catalyst activity in a reversible manner. (C) 1997 Elsevier Science S.A.