Propan-2-ol transformation on simple metal oxides TiO2, ZrO2 and CeO2

The propan-2-ol dehydration or dehydrogenation over three simple metal oxides (TiO2, ZrO2 and CeO2) was carried out in helium, dihydrogen or air flow. at temperatures in the (473-623 K) range. Propan-2-ol decomposition on metal oxide surfaces has been used as an acid-base test. On TiO2, ZrO2 or CeO2, it appears that propene and acetone formation sites are not specific and it is difficult to deduce surfaces properties from activities and selectivities observed. In helium and dihydrogen, for all the metal oxides, temperature increase always favours propene formation. In air, the three metal oxides used are more active and their selectivity in acetone is more important than in helium or dihydrogen. The results clearly show that propanol transformation cannot be a simple test of acidity. Particularly, on ceria, results suggest that redox property and the high lability of lattice oxygen contribute to products formations, involving oxygen vacancies. (C) 2001 Elsevier Science B.V. All rights reserved.