| 摘要 |
Heterogenous catalytic partial gas phase oxidation of propylene to acrylic acid comprises introducing a reaction gas initial mixture (I) containing propylene and molecular oxygen and an inert dilution gas in a first reaction stage at increased temperature into a first reaction zone; reducing the temperature of the product gas mixture 1 and adding a secondary gas in the form of molecular oxygen and/or inert gas to the product gas mixture 1; and subsequently introducing the product gas mixture 1 and an inert dilution gas, into a second reaction stage at increased temperature. Procedure for heterogenous catalytic partial gas phase oxidation of propylene to acrylic acid comprises introducing a reaction gas initial mixture (I) containing propylene and molecular oxygen in a molar ratio of >= 1 and at least an inert dilution gas in a first reaction stage at increased temperature into a first reaction zone through at least a first catalyst bed, whose catalysts exhibit at least a multi-metal oxide (A) containing molybdenum, iron and bismuth as active mass, in such a manner that the propylene conversion during a single passage through the catalyst bed is >= 90 mol.% and the resulting selectivity of the acrolein formation and the acrylic acid by-product formation is >= 80 mol.%; reducing the temperature of the product gas mixture 1 leaving the first reaction stage optionally by direct or indirect cooling and adding a secondary gas in the form of molecular oxygen and/or inert gas to the product gas mixture (I); and subsequently introducing the product gas mixture 1, as the reaction gas initial mixture (II) containing molecular oxygen and acrolein in a molar ratio of >= 0.5 and at least an inert dilution gas, into a second reaction stage at increased temperature, through at least a second catalyst bed, whose catalysts exhibit multi-metal oxide (A1)containing at least molybdenum and vanadium as active mass in such a manner that the acrolein conversion during a single passage through the catalyst bed is >= 95 mol.% and the selectivity of the acrylic acid formation that spreads over both the reaction stage is >= 70 mol.%, related to the converted propylene, where (I) contains up to 3 mol.% of cyclopropane, based on the molar quantity of propane, and is produced by simultaneously using raw propylene. |
