PRODUCTION OF METHACRYLIC ACID

摘要

PROBLEM TO BE SOLVED: To provide a method for producing methacrylic acid in high yield and stably for a long period by vapor phase catalytic oxidation of methacrolein. SOLUTION: This method for producing methacrylic acid comprises vapor phase catalytic oxidization of methacrolein with molecular oxygen or molecular oxygen-containing gas by using a fixed bed multitubular reactor; wherein (1) the catalytic bed in each of the reaction tubes is divided into at least 2 tiers in the direction of tubular axis to provide a plurality of reaction zones and (2) as for the catalyst packed in each of the reaction zones, the catalytically active component per unit volume of the reaction tube is made to decrease from the entrance of raw material gas toward the exit.