| 摘要 |
The invention relates to a method for improving or optimising a catalyst for producing phthalic anhydride by the gas phase oxidation of o-xylol and/or naphthalene, said method comprising the following steps: a) provision of a starting catalyst (K) containing at least one first catalyst layer on the gas entry side and a second catalyst layer lying closer to the gas exit side, each of said catalyst layers preferably comprising an active substance containing TiO2; b) replacement of part of the first catalyst layer by a catalyst layer connected upstream with a more intense action than the first catalyst layer, to provide an improved catalyst. The invention also relates to an improved catalyst that can be obtained according to said method.
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