| 摘要 |
PROBLEM TO BE SOLVED: To provide a new method for producing methacrylic acid comprising catalytic vapor phase oxidation reaction of isobutylene or the like and enabling a forming and also viscous product formation to be suppressed in the steps of condensation, recovery, releasing and scrubbing included in the method. SOLUTION: This method for producing methacrylic acid comprises the steps of (A) catalytic vapor phase oxidation reaction of one compound or a mixture of at least two compounds selected from isobutylene, t-butanol, methacrolein, isobutylaldehyde and isobutyric acid, (B) condensation of the reaction product gas obtained in the step A, (C) recovery of the methacrolein and methacrylic acid in the gas discharged from the step B, (D) releasing methacrolein from the aqueous phase discharged from the step C, and (E) scrubbing the gas discharged from the step C; wherein this method is characterized by involving using a silica-based defoaming agent in at least one step selected from the steps B, C, D and E.
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