Patent ID: 6395936
Filing Date: 2002-05-28
Classification: B01J,C07C

Abstract:
A process for the catalytic gas-phase oxidation of propene to acrolein, in which a reaction gas starting mixture comprising propene, molecular oxygen and at least one inert gas, at least 20% by volume of which consists of molecular nitrogen, and containing the molecular oxygen and the propene in a molar ratio O2:C3H6 of &gE;1 is passed, at elevated temperatures, over a fixed-bed catalyst, whose active material is at least one molybdenum- and/or tungsten- and bismuth-, tellurium-, antimony-, tin- and/or copper-containing multimetal oxide, in such a way that the propene conversion in a single pass is &gE;90 mol % and the associated selectivity of the acrolein formation and of the acrylic acid byproduct formation together is &gE;90 mol %, whereina) the loading of the fixed-bed catalyst with the propene contained in the reaction gas starting mixture is &gE;160 l(S.T.P.) of propene per l of catalyst bed per h, b) the fixed-bed catalyst consists of a catalyst bed arranged in two spatially successive reaction zones A, B, the temperature of the reaction zone A being from 300 to 390Â° C. and the temperature of the reaction zone B being from 305 to 420Â° C. and at the same time being at least 50Â° C. above the temperature of the reaction zone A, c) the reaction gas starting mixture flows first through the reaction zone A and then through the reaction zone B and d) the reaction zone A extends to a propene conversion of from 40 to 80 mol %.