Naphthalene heterogeneous catalysis

Attenlion should be drawn to ihe use of tin oxide systems as heterogeneous catalysts. The oldest and mosi extensively patented systems are the mixed lin-vanadium oxide catalysis for the oxidation of aromatic compounds such as benzene, toluene, xylenes and naphthalene in the. synthesis of organic acids and acid anhydride.s. More recenily mixed lin-aniimony oxides have been applied lo the selective oxidaiion and ammoxidaiion of propylene to acrolein, acrylic acid and acrylonilrile. 

The catalytic properties of V-HMS were investigated in detail by Reddy et al. [44], Naphthalene and 2-methylnaphthalene were oxidized at the 1,4-positions to afford the related 1,4-naphthoquinones. Under analogous conditions, 2,6-DTBP (83 % conv.) led to the corresponding p-quinone (87 %) and p-diphenoqui-none (4 %). The relative role of homogeneous and heterogeneous pathways in catalysis remained uncertain, because different amounts of V ions were released into the liquid phase under different conditions. 

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