| abstract |
A method for producing a ring-shaped non-supported catalyst by heat treatment of the ring-shaped non-supported catalyst precursor, and the side surface compressive strength of the ring-shaped non-supported catalyst precursor is ≧ 12N and ≦ 23N. Furthermore, a ring-shaped unsupported catalyst having a special pore structure generated in this case, and the use of the ring-shaped unsupported catalyst for producing (meth) acrolein by gas phase catalytic partial oxidation. |