Abstract: It is intended to provide an acetic acid production method capable of industrially advantageously separating and removing a by-product acetaldehyde in the separation step of separating a process stream into aqueous and organic phases. In the present invention, the separation step satisfies, for example, the following conditions (vi) to (viii), and at least a portion of the aqueous phase is treated in the acetaldehyde separation and removal step: (vi) acetaldehyde concentrations in the aqueous and/or organic phases are not more than 28.1 mass % and not more than 24.8 mass %, respectively; (vii) a separation temperature is not more than 70° C.; and (viii) methyl acetate concentrations in the aqueous and/or organic phases are not more than 12.0 mass % and not more than 47.6 mass %, respectively, and/or the sum of the methyl acetate concentrations in the aqueous and organic phases is not more than 59.6 mass %.

Abstract: It is intended to provide an acetic acid production method capable of industrially advantageously separating and removing a by-product acetaldehyde in the separation step of separating a process stream into aqueous and organic phases. In the present invention, the separation step satisfies, for example, the following conditions (vi) to (viii), and at least a portion of the aqueous phase is treated in the acetaldehyde separation and removal step: (vi) acetaldehyde concentrations in the aqueous and/or organic phases are not more than 28.1 mass % and not more than 24.8 mass %, respectively; (vii) a separation temperature is not more than 70° C.; and (viii) methyl acetate concentrations in the aqueous and/or organic phases are not more than 12.0 mass % and not more than 47.6 mass %, respectively, and/or the sum of the methyl acetate concentrations in the aqueous and organic phases is not more than 59.6 mass %.