Patent ID: 9073845
Filing Date: 2015-07-07
Classification: B01J,C07C

Abstract:
1. A method for producing acrolein and acrylic acid by the catalytic gas-phase oxidation of propylene with molecular oxygen or molecular oxygen-containing gas by a fixed-bed multitubular reactor which has been filled with catalyst, which method comprises filling each of reaction tubes of a fixed-bed multitubular reactor with at least two species of catalysts each of which essentially comprises, as catalytically active components, oxide of molybdenum, oxide of bismuth and oxide of iron and/or composite oxide of at least two of said elements, said at least two species of catalysts being different in the ratio of D1/D2, D1 denoting the proportion of the total pore volume of pores whose pore diameter falls within the range of at least 0.03 μm and less than 0.3 μm to the total pore volume of the whole pores, and D2 denoting the proportion of the total pore volume of pores whose pore diameter falls within the range of at least 0.3 μm and at most 3 μm to the total pore volume of the whole pores, in such a manner that at least two reaction zones are formed axially in each of the reaction tubes.