In a process for heterogeneously catalyzed partial gas phase oxidation of propene
to acrylic acid, the starting reaction gas mixture is oxidized at a propene loading
of 160 l(STP)/lh in a first reaction stage over a fixed catalyst bed
1 which is accommodated in two successive reaction zones A, B, and the acrolein-containing
product gas mixture of the first reaction stage is subsequently oxidized in a second
reaction stage over a fixed catalyst bed 2 which is a accommodated in two
successive reaction zones C, D, the highest temperature of the reaction gas mixture
within reaction zone A being above the highest temperature of the reaction gas
mixture within reaction zone B and the highest temperature of the reaction gas
mixture within reaction zone C being above the highest temperature of the reaction
gas mixture within reaction zone D.
