CATALYTIC GAS-PHASE OXIDATION OF METHACROLEIN TO METHACRYLIC ACID

摘要

A process for the catalytic gas-phase oxidation of methacrolein to methacrylic acid in a fixed-bed reactor with contacting tubes, at elevated temperature on catalytically active oxides with a conversion of methacrolein for a single pass of from 40 to 95 mol%, wherein the reaction temperature in the flow direction along the contacting tubes in a first reaction zone from entry of the starting reaction gases containing the reactants into the contacting tubes is from 280 to 340 DEG C. until a methacrolein conversion of from 20 to 40% is reached, and the reaction temperature is subsequently reduced by a total of from 5 DEG to 40 DEG C., abruptly or successively in steps or continuously along the contacting tubes until a methacrolein conversion of from 45 to 95% has been reached, with the proviso that the reaction temperature in this second reaction zone is not lower than 260 DEG C.