| abstract |
A catalyst for the oxidation of aromatic or unsaturated aliphatic hydrocarbons which contains in the active material from 60 to 99 percent by weight of titanium dioxide and/or zirconium dioxide, from 1 to 40 percent by weight of vanadium pentoxide and up to 6 percent by weight of combined phosphorus, and which contains from 0 to 0.3 percent by weight of phosphorus in the outer layer and more than 0.3 percent up to 6 percent by weight of phosphorus in the remaining catalytic material. |