Ε½
. The catalytic abilities of commercial K10-montmorillonite and molecular sieves 4 A and 13 X vs. oxidation of alcohols by t-butyl hydroperoxide were investigated. The K10-montmorillonite-catalyzed oxidation of secondary benzylic alcohols was found to proceed in good yield and selectivity with almost all the substrates, while K10-montmorillonite Bronsted Ε½ . acidity induced undesired side reactions with formation of elimination products and mixed ethers and peroxides when an electron-donating group was present in 4-position of the aromatic ring. Structurally different aluminosilicates, 4 A molecular sieves, showed a very close behaviour since oxidation of benzylic, linear and cyclic aliphatic alcohols occurred with comparable efficiency and selectivity. The experimental results were found to be in agreement with a mechanistic pathway Ε½ . involving an Oppenhauer-type oxidation taking place on the edge catalytic sites as regards K10-montmorillonite and on the Ε½ . external surface as regards 4 A molecular sieves . In the presence of aluminosilicates, capable to accommodate the reactants Ε½ . in the internal cavities and channels as 13 X molecular sieves , a very enhanced reactivity was observed, but besides the fast formation of carbonyl compounds, other competitive side reactions of oxidative fission took place.