ABSTRACT
H. Oxidation of Propene to Acetone As discussed in Section III. B, the activation of the propene molecule to form allyl species may be considered as an acid-base process, involving the participation of surface 0 2-ions of base character. A different type of propene activation will take place on surfaces containing Bronsted acid centers, where carbonium ion mechanism may operate, resulting in the formation of propoxide type adsorption complex. In the presence of water the complex decomposes to produce isopropyl alcohol and regenerated surface Bronsted acid centers. When redox centers are also present at the catalyst surface, dehydrogenation of isopropyl alcohol may follow its formation on acid centers, resulting in the appearance of acetone. This reaction was discovered in 1968 [100,101] and since then is known as oxyhydration. Many mixed transition metal oxides containing Mo03 have been shown to be active in the oxyhydration of propene. The best catalysts found so far are Sn02-Mo03 and C0304-Mo03. In both cases the highest activity was observed for samples containing no more than about 30% of Mo03, the reaction being carried out in the temperature range
