Patent ID: 10815181

Abstract:
Provided is a method for industrially efficiently producing acetic acid yielding a good potassium permanganate test result, without costing much. The acetic acid production method according to the present invention includes a carbonylation step, a separation step, a recycling step, a liquid-liquid separation step, and an acetaldehyde-removing step of treating an object, where the object is selected from at least a part of at least one of the aqueous phase and the organic phase on the basis of a factor(s) selected from a liquid temperature in the liquid-liquid separation in the liquid-liquid separation step, an acetaldehyde concentration in at least one of the aqueous phase and the organic phase, an acetaldehyde partition coefficient, a methyl acetate concentration in at least one of the aqueous phase and the organic phase, and a methyl acetate partition coefficient. In the first acetic acid stream in the separation step, a crotonaldehyde concentration is controlled to 2.2 ppm by mass or less, and the ratio (CCR/CECR) of a crotonaldehyde concentration CCR (ppm by mass) to an 2-ethylcrotonaldehyde concentration CECR (ppm by mass) is regulated.