| abstract |
The invention discloses a catalyst comprising a silica carrier, a modifier metal and a catalytic alkali metal. The silica support has a multimodal pore size distribution comprising a mesopore pore size distribution having an average pore diameter in the range of 2 nm to 50 nm and a pore volume of the mesopores of at least 0.1 cm 3 /g, and having A macropore pore size distribution with an average pore diameter of greater than 50 nm and a pore volume of said macropores of at least 0.1 cm 3 /g. The level of catalytic alkali metal on the silica support is at least 2 mol%. The modifier metal is selected from Mg, B, Al, Ti, Zr and Hf. The present invention also discloses a method for producing the catalyst, a method for producing an ethylenically unsaturated carboxylic acid or carboxylic acid ester in the presence of the catalyst, and a process for producing an ethylenically unsaturated acid or ester in the presence of the catalyst. |