METHOD FOR PROLONGED HETEROGENEOUS CATALYSED PARTIAL GAS-PHASE OXIDATION OF PROPYLENE TO ACROLEIN Russian patent published in 2015 - IPC C07C45/35 C07C47/22 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for prolonged heterogeneous catalysed partial gas-phase oxidation of propylene to acrolein. According to said method, an initial reaction gas mixture containing propylene, molecular oxygen and at least one inert gas, the molar ratio of molecular oxygen to propylene O₂:C₃H₆ in which is ≥1:1, is passed through a fixed catalyst bed, the active mass of which is at least one polymetal oxide, containing the following elements: molybdenum, iron and bismuth, under the condition that the fixed catalyst bed is ordered in two spatially consecutive temperature zones A and B. Both the temperature of the temperature zone A (T^A) and the temperature of the temperature zone B (T^B) is in the range of 280 to 420°C. The initial reaction gas mixture passes through temperature zones A and B in the time sequence "first A, then B", wherein the temperature zone A continues until the degree of conversion of propylene (U^A) contained in the initial reaction gas mixture is 45 to 85 mol %, while the degree of conversion of propylene in the temperature zone B rises to a value U^B≥90 mol %, where when the initial reaction gas mixture passes through the common fixed catalyst bed once, selectivity of formation of acrolein with respect to the converted propylene is ≥80 mol %, the loading of the fixed catalyst bed with propylene contained in the initial reaction gas mixture is ≥140 nl propylene per litre of the fixed catalyst bed per hour; after loading a fresh fixed catalyst bed, temperatures T^A and T^B are such that the difference T^BA=T^B-T^A is greater than 0°C; and then in order to counteract the deterioration of quality of the fixed catalyst bed as the duration of the production increases, at least one of the temperatures T^A or T^B is raised. At least one of the two temperatures T^A and T^B is raised such that as the duration of the production process increases, the difference ΔT^BA=T^B-T^A increases.

EFFECT: method prolongs the service life of a fixed catalyst bed with satisfactory selectivity of formation of acrolein.

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